Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Constants](https://developer.android.com/reference/javax/crypto/Cipher#constants) \| [Protected Ctors](https://developer.android.com/reference/javax/crypto/Cipher#proctors) \| [Methods](https://developer.android.com/reference/javax/crypto/Cipher#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/javax/crypto/Cipher#inhmethods)
# Cipher
`
public
class
Cipher
`
`
extends https://developer.android.com/reference/java/lang/Object
`
`
`
|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | javax.crypto.Cipher |
|---|
| Known direct subclasses [NullCipher](https://developer.android.com/reference/javax/crypto/NullCipher) |---|---| | [NullCipher](https://developer.android.com/reference/javax/crypto/NullCipher) | The NullCipher class is a class that provides an "identity cipher" -- one that does not transform the plain text. | |
*** ** * ** ***
This class provides the functionality of a cryptographic cipher for
encryption and decryption. It forms the core of the Java Cryptographic
Extension (JCE) framework.
In order to create a Cipher object, the application calls the
Cipher's `getInstance` method, and passes the name of the
requested *transformation* to it. Optionally, the name of a provider
may be specified.
A *transformation* is a string that describes the operation (or
set of operations) to be performed on the given input, to produce some
output. A transformation always includes the name of a cryptographic
algorithm (e.g., *DES*), and may be followed by a feedback mode and
padding scheme.
A transformation is of the form:
- "*algorithm/mode/padding*" or
- "*algorithm*"
(in the latter case,
provider-specific default values for the mode and padding scheme are used).
For example, the following is a valid transformation:
Cipher c = Cipher.getInstance("DES/CBC/PKCS5Padding");
Using modes such as `CFB` and `OFB`, block ciphers can encrypt data in units smaller than the cipher's actual block size. When requesting such a mode, you may optionally specify the number of bits to be processed at a time by appending this number to the mode name as shown in the "`DES/CFB8/NoPadding`" and "`DES/OFB32/PKCS5Padding`" transformations. If no such number is specified, a provider-specific default is used. (For example, the SunJCE provider uses a default of 64 bits for DES.) Thus, block ciphers can be turned into byte-oriented stream ciphers by using an 8 bit mode such as CFB8 or OFB8.
Modes such as Authenticated Encryption with Associated Data (AEAD)
provide authenticity assurances for both confidential data and
Additional Associated Data (AAD) that is not encrypted. (Please see
[RFC 5116](http://www.ietf.org/rfc/rfc5116.txt) for more
information on AEAD and AEAD algorithms such as GCM/CCM.) Both
confidential and AAD data can be used when calculating the
authentication tag (similar to a `https://developer.android.com/reference/javax/crypto/Mac`). This tag is appended
to the ciphertext during encryption, and is verified on decryption.
AEAD modes such as GCM/CCM perform all AAD authenticity calculations
before starting the ciphertext authenticity calculations. To avoid
implementations having to internally buffer ciphertext, all AAD data
must be supplied to GCM/CCM implementations (via the `updateAAD` methods) **before** the ciphertext is processed (via
the `update` and `doFinal` methods).
Note that GCM mode has a uniqueness requirement on IVs used in
encryption with a given key. When IVs are repeated for GCM
encryption, such usages are subject to forgery attacks. Thus, after
each encryption operation using GCM mode, callers should re-initialize
the cipher objects with GCM parameters which has a different IV value.
```
GCMParameterSpec s = ...;
cipher.init(..., s);
// If the GCM parameters were generated by the provider, it can
// be retrieved by:
// cipher.getParameters().getParameterSpec(GCMParameterSpec.class);
cipher.updateAAD(...); // AAD
cipher.update(...); // Multi-part update
cipher.doFinal(...); // conclusion of operation
// Use a different IV value for every encryption
byte[] newIv = ...;
s = new GCMParameterSpec(s.getTLen(), newIv);
cipher.init(..., s);
...
```
Android provides the following `Cipher` transformations:
| Algorithm | Modes | Paddings | Supported API Levels | Notes |
|---|---|---|---|---|
| AES | CBC CFB CTR CTS ECB OFB | ISO10126Padding NoPadding PKCS5Padding | 1+ | |
| AES | GCM | NoPadding | 10+ | |
| AES | GCM-SIV | NoPadding | 30+ | |
| AES_128 | CBC ECB | NoPadding PKCS5Padding | 26+ | |
| AES_128 | GCM | NoPadding | 26+ | |
| AES_128 | GCM-SIV | NoPadding | 30+ | |
| AES_256 | CBC ECB | NoPadding PKCS5Padding | 26+ | |
| AES_256 | GCM | NoPadding | 26+ | |
| AES_256 | GCM-SIV | NoPadding | 30+ | |
| ARC4 | ECB | NoPadding | 10+ | |
| ARC4 | NONE | NoPadding | 28+ | |
| BLOWFISH | CBC CFB CTR CTS ECB OFB | ISO10126Padding NoPadding PKCS5Padding | 10+ | |
| ChaCha20 | NONE Poly1305 | NoPadding | 28+ | ChaCha with 20 rounds, 96-bit nonce, and 32-bit counter as described in RFC 7539. |
| DES | CBC CFB CTR CTS ECB OFB | ISO10126Padding NoPadding PKCS5Padding | 1+ | |
| DESede | CBC CFB CTR CTS ECB OFB | ISO10126Padding NoPadding PKCS5Padding | 1+ | |
| RSA | ECB NONE | NoPadding OAEPPadding PKCS1Padding | 1+ | |
| RSA | ECB NONE | OAEPwithSHA-1andMGF1Padding OAEPwithSHA-256andMGF1Padding | 10+ | |
| RSA | ECB NONE | OAEPwithSHA-224andMGF1Padding OAEPwithSHA-384andMGF1Padding OAEPwithSHA-512andMGF1Padding | 23+ | |
These transformations are described in the [Cipher section](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#Cipher) of the Java Cryptography Architecture Standard Algorithm Name Documentation.
**See also:**
- `https://developer.android.com/reference/javax/crypto/KeyGenerator`
- `https://developer.android.com/reference/javax/crypto/SecretKey`
## Summary
| ### Constants ||
|---|---|
| `int` | `https://developer.android.com/reference/javax/crypto/Cipher#DECRYPT_MODE` Constant used to initialize cipher to decryption mode. |
| `int` | `https://developer.android.com/reference/javax/crypto/Cipher#ENCRYPT_MODE` Constant used to initialize cipher to encryption mode. |
| `int` | `https://developer.android.com/reference/javax/crypto/Cipher#PRIVATE_KEY` Constant used to indicate the to-be-unwrapped key is a "private key". |
| `int` | `https://developer.android.com/reference/javax/crypto/Cipher#PUBLIC_KEY` Constant used to indicate the to-be-unwrapped key is a "public key". |
| `int` | `https://developer.android.com/reference/javax/crypto/Cipher#SECRET_KEY` Constant used to indicate the to-be-unwrapped key is a "secret key". |
| `int` | `https://developer.android.com/reference/javax/crypto/Cipher#UNWRAP_MODE` Constant used to initialize cipher to key-unwrapping mode. |
| `int` | `https://developer.android.com/reference/javax/crypto/Cipher#WRAP_MODE` Constant used to initialize cipher to key-wrapping mode. |
| ### Protected constructors ||
|---|---|
| ` https://developer.android.com/reference/javax/crypto/Cipher#Cipher(javax.crypto.CipherSpi,%20java.security.Provider,%20java.lang.String)(https://developer.android.com/reference/javax/crypto/CipherSpi cipherSpi, https://developer.android.com/reference/java/security/Provider provider, https://developer.android.com/reference/java/lang/String transformation) ` Creates a Cipher object. |
| ### Public methods ||
|---|---|
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#doFinal(byte[],%20int,%20int,%20byte[])(byte[] input, int inputOffset, int inputLen, byte[] output) ` Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#doFinal(byte[],%20int)(byte[] output, int outputOffset) ` Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized. |
| ` final byte[]` | ` https://developer.android.com/reference/javax/crypto/Cipher#doFinal()() ` Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialized. |
| ` final byte[]` | ` https://developer.android.com/reference/javax/crypto/Cipher#doFinal(byte[])(byte[] input) ` Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#doFinal(byte[],%20int,%20int,%20byte[],%20int)(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset) ` Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#doFinal(java.nio.ByteBuffer,%20java.nio.ByteBuffer)(https://developer.android.com/reference/java/nio/ByteBuffer input, https://developer.android.com/reference/java/nio/ByteBuffer output) ` Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
| ` final byte[]` | ` https://developer.android.com/reference/javax/crypto/Cipher#doFinal(byte[],%20int,%20int)(byte[] input, int inputOffset, int inputLen) ` Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. |
| ` final https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/javax/crypto/Cipher#getAlgorithm()() ` Returns the algorithm name of this `Cipher` object. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#getBlockSize()() ` Returns the block size (in bytes). |
| ` final https://developer.android.com/reference/javax/crypto/ExemptionMechanism` | ` https://developer.android.com/reference/javax/crypto/Cipher#getExemptionMechanism()() ` Returns the exemption mechanism object used with this cipher. |
| ` final byte[]` | ` https://developer.android.com/reference/javax/crypto/Cipher#getIV()() ` Returns the initialization vector (IV) in a new buffer. |
| ` static final https://developer.android.com/reference/javax/crypto/Cipher` | ` https://developer.android.com/reference/javax/crypto/Cipher#getInstance(java.lang.String)(https://developer.android.com/reference/java/lang/String transformation) ` Returns a `Cipher` object that implements the specified transformation. |
| ` static final https://developer.android.com/reference/javax/crypto/Cipher` | ` https://developer.android.com/reference/javax/crypto/Cipher#getInstance(java.lang.String,%20java.lang.String)(https://developer.android.com/reference/java/lang/String transformation, https://developer.android.com/reference/java/lang/String provider) ` Returns a `Cipher` object that implements the specified transformation. |
| ` static final https://developer.android.com/reference/javax/crypto/Cipher` | ` https://developer.android.com/reference/javax/crypto/Cipher#getInstance(java.lang.String,%20java.security.Provider)(https://developer.android.com/reference/java/lang/String transformation, https://developer.android.com/reference/java/security/Provider provider) ` Returns a `Cipher` object that implements the specified transformation. |
| ` static final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#getMaxAllowedKeyLength(java.lang.String)(https://developer.android.com/reference/java/lang/String transformation) ` Returns the maximum key length for the specified transformation according to the installed JCE jurisdiction policy files. |
| ` static final https://developer.android.com/reference/java/security/spec/AlgorithmParameterSpec` | ` https://developer.android.com/reference/javax/crypto/Cipher#getMaxAllowedParameterSpec(java.lang.String)(https://developer.android.com/reference/java/lang/String transformation) ` Returns an AlgorithmParameterSpec object which contains the maximum cipher parameter value according to the jurisdiction policy file. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)(int inputLen) ` Returns the length in bytes that an output buffer would need to be in order to hold the result of the next `update` or `doFinal` operation, given the input length `inputLen` (in bytes). |
| ` final https://developer.android.com/reference/java/security/AlgorithmParameters` | ` https://developer.android.com/reference/javax/crypto/Cipher#getParameters()() ` Returns the parameters used with this cipher. |
| ` final https://developer.android.com/reference/java/security/Provider` | ` https://developer.android.com/reference/javax/crypto/Cipher#getProvider()() ` Returns the provider of this `Cipher` object. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.Key,%20java.security.AlgorithmParameters)(int opmode, https://developer.android.com/reference/java/security/Key key, https://developer.android.com/reference/java/security/AlgorithmParameters params) ` Initializes this cipher with a key and a set of algorithm parameters. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.cert.Certificate,%20java.security.SecureRandom)(int opmode, https://developer.android.com/reference/java/security/cert/Certificate certificate, https://developer.android.com/reference/java/security/SecureRandom random) ` Initializes this cipher with the public key from the given certificate and a source of randomness. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.Key,%20java.security.SecureRandom)(int opmode, https://developer.android.com/reference/java/security/Key key, https://developer.android.com/reference/java/security/SecureRandom random) ` Initializes this cipher with a key and a source of randomness. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.Key,%20java.security.spec.AlgorithmParameterSpec)(int opmode, https://developer.android.com/reference/java/security/Key key, https://developer.android.com/reference/java/security/spec/AlgorithmParameterSpec params) ` Initializes this cipher with a key and a set of algorithm parameters. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.Key)(int opmode, https://developer.android.com/reference/java/security/Key key) ` Initializes this cipher with a key. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.Key,%20java.security.spec.AlgorithmParameterSpec,%20java.security.SecureRandom)(int opmode, https://developer.android.com/reference/java/security/Key key, https://developer.android.com/reference/java/security/spec/AlgorithmParameterSpec params, https://developer.android.com/reference/java/security/SecureRandom random) ` Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.cert.Certificate)(int opmode, https://developer.android.com/reference/java/security/cert/Certificate certificate) ` Initializes this cipher with the public key from the given certificate. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#init(int,%20java.security.Key,%20java.security.AlgorithmParameters,%20java.security.SecureRandom)(int opmode, https://developer.android.com/reference/java/security/Key key, https://developer.android.com/reference/java/security/AlgorithmParameters params, https://developer.android.com/reference/java/security/SecureRandom random) ` Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness. |
| ` final https://developer.android.com/reference/java/security/Key` | ` https://developer.android.com/reference/javax/crypto/Cipher#unwrap(byte[],%20java.lang.String,%20int)(byte[] wrappedKey, https://developer.android.com/reference/java/lang/String wrappedKeyAlgorithm, int wrappedKeyType) ` Unwrap a previously wrapped key. |
| ` final byte[]` | ` https://developer.android.com/reference/javax/crypto/Cipher#update(byte[])(byte[] input) ` Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#update(byte[],%20int,%20int,%20byte[])(byte[] input, int inputOffset, int inputLen, byte[] output) ` Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
| ` final byte[]` | ` https://developer.android.com/reference/javax/crypto/Cipher#update(byte[],%20int,%20int)(byte[] input, int inputOffset, int inputLen) ` Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#update(java.nio.ByteBuffer,%20java.nio.ByteBuffer)(https://developer.android.com/reference/java/nio/ByteBuffer input, https://developer.android.com/reference/java/nio/ByteBuffer output) ` Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
| ` final int` | ` https://developer.android.com/reference/javax/crypto/Cipher#update(byte[],%20int,%20int,%20byte[],%20int)(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset) ` Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#updateAAD(byte[],%20int,%20int)(byte[] src, int offset, int len) ` Continues a multi-part update of the Additional Authentication Data (AAD), using a subset of the provided buffer. |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#updateAAD(java.nio.ByteBuffer)(https://developer.android.com/reference/java/nio/ByteBuffer src) ` Continues a multi-part update of the Additional Authentication Data (AAD). |
| ` final void` | ` https://developer.android.com/reference/javax/crypto/Cipher#updateAAD(byte[])(byte[] src) ` Continues a multi-part update of the Additional Authentication Data (AAD). |
| ` final byte[]` | ` https://developer.android.com/reference/javax/crypto/Cipher#wrap(java.security.Key)(https://developer.android.com/reference/java/security/Key key) ` Wrap a key. |
| ### Inherited methods |
|---|---|
| From class ` https://developer.android.com/reference/java/lang/Object ` |---|---| | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/Object#clone()() ` Creates and returns a copy of this object. | | ` boolean` | ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` https://developer.android.com/reference/java/lang/Object#finalize()() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final https://developer.android.com/reference/java/lang/Class` | ` https://developer.android.com/reference/java/lang/Object#getClass()() ` Returns the runtime class of this `Object`. | | ` int` | ` https://developer.android.com/reference/java/lang/Object#hashCode()() ` Returns a hash code value for the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notify()() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notifyAll()() ` Wakes up all threads that are waiting on this object's monitor. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/lang/Object#toString()() ` Returns a string representation of the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait()() ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*. | ||
## Constants
### DECRYPT_MODE
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int DECRYPT_MODE
```
Constant used to initialize cipher to decryption mode.
Constant Value:
2
(0x00000002)
### ENCRYPT_MODE
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int ENCRYPT_MODE
```
Constant used to initialize cipher to encryption mode.
Constant Value:
1
(0x00000001)
### PRIVATE_KEY
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int PRIVATE_KEY
```
Constant used to indicate the to-be-unwrapped key is a "private key".
Constant Value:
2
(0x00000002)
### PUBLIC_KEY
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int PUBLIC_KEY
```
Constant used to indicate the to-be-unwrapped key is a "public key".
Constant Value:
1
(0x00000001)
### SECRET_KEY
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int SECRET_KEY
```
Constant used to indicate the to-be-unwrapped key is a "secret key".
Constant Value:
3
(0x00000003)
### UNWRAP_MODE
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int UNWRAP_MODE
```
Constant used to initialize cipher to key-unwrapping mode.
Constant Value:
4
(0x00000004)
### WRAP_MODE
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int WRAP_MODE
```
Constant used to initialize cipher to key-wrapping mode.
Constant Value:
3
(0x00000003)
## Protected constructors
### Cipher
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
protected Cipher (CipherSpi cipherSpi,
Provider provider,
String transformation)
```
Creates a Cipher object.
| Parameters ||
|---|---|
| `cipherSpi` | `CipherSpi`: the delegate
|
| `provider` | `Provider`: the provider
|
| `transformation` | `String`: the transformation
|
## Public methods
### doFinal
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int doFinal (byte[] input,
int inputOffset,
int inputLen,
byte[] output)
```
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The first `inputLen` bytes in the `input`
buffer, starting at `inputOffset` inclusive, and any input
bytes that may have been buffered during a previous `update`
operation, are processed, with padding (if requested) being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
The result is stored in the `output` buffer.
If the `output` buffer is too small to hold the result,
a `ShortBufferException` is thrown. In this case, repeat this
call with a larger output buffer. Use
`https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)` to determine how big
the output buffer should be.
Upon finishing, this method resets this cipher object to the state
it was in when previously initialized via a call to `init`.
That is, the object is reset and available to encrypt or decrypt
(depending on the operation mode that was specified in the call to
`init`) more data.
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Note: this method should be copy-safe, which means the
`input` and `output` buffers can reference
the same byte array and no unprocessed input data is overwritten
when the result is copied into the output buffer.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| `inputOffset` | `int`: the offset in `input` where the input starts
|
| `inputLen` | `int`: the input length
|
| `output` | `byte`: the buffer for the result
|
| Returns ||
|---|---|
| `int` | the number of bytes stored in `output`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/AEADBadTagException` | if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value |
| `https://developer.android.com/reference/javax/crypto/BadPaddingException` | if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
| `https://developer.android.com/reference/javax/crypto/ShortBufferException` | if the given output buffer is too small to hold the result |
### doFinal
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int doFinal (byte[] output,
int outputOffset)
```
Finishes a multiple-part encryption or decryption operation, depending
on how this cipher was initialized.
Input data that may have been buffered during a previous
`update` operation is processed, with padding (if requested)
being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
The result is stored in the `output` buffer, starting at
`outputOffset` inclusive.
If the `output` buffer is too small to hold the result,
a `ShortBufferException` is thrown. In this case, repeat this
call with a larger output buffer. Use
`https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)` to determine how big
the output buffer should be.
Upon finishing, this method resets this cipher object to the state
it was in when previously initialized via a call to `init`.
That is, the object is reset and available to encrypt or decrypt
(depending on the operation mode that was specified in the call to
`init`) more data.
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
| Parameters ||
|---|---|
| `output` | `byte`: the buffer for the result
|
| `outputOffset` | `int`: the offset in `output` where the result is stored
|
| Returns ||
|---|---|
| `int` | the number of bytes stored in `output`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/AEADBadTagException` | if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value |
| `https://developer.android.com/reference/javax/crypto/BadPaddingException` | if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
| `https://developer.android.com/reference/javax/crypto/ShortBufferException` | if the given output buffer is too small to hold the result |
### doFinal
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final byte[] doFinal ()
```
Finishes a multiple-part encryption or decryption operation, depending
on how this cipher was initialized.
Input data that may have been buffered during a previous
`update` operation is processed, with padding (if requested)
being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
The result is stored in a new buffer.
Upon finishing, this method resets this cipher object to the state
it was in when previously initialized via a call to `init`.
That is, the object is reset and available to encrypt or decrypt
(depending on the operation mode that was specified in the call to
`init`) more data.
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
| Returns ||
|---|---|
| `byte[]` | the new buffer with the result
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/AEADBadTagException` | if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value |
| `https://developer.android.com/reference/javax/crypto/BadPaddingException` | if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
### doFinal
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final byte[] doFinal (byte[] input)
```
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The bytes in the `input` buffer, and any input bytes that
may have been buffered during a previous `update` operation,
are processed, with padding (if requested) being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
The result is stored in a new buffer.
Upon finishing, this method resets this cipher object to the state
it was in when previously initialized via a call to `init`.
That is, the object is reset and available to encrypt or decrypt
(depending on the operation mode that was specified in the call to
`init`) more data.
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| Returns ||
|---|---|
| `byte[]` | the new buffer with the result
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/AEADBadTagException` | if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value |
| `https://developer.android.com/reference/javax/crypto/BadPaddingException` | if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
### doFinal
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int doFinal (byte[] input,
int inputOffset,
int inputLen,
byte[] output,
int outputOffset)
```
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The first `inputLen` bytes in the `input`
buffer, starting at `inputOffset` inclusive, and any input
bytes that may have been buffered during a previous
`update` operation, are processed, with padding
(if requested) being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
The result is stored in the `output` buffer, starting at
`outputOffset` inclusive.
If the `output` buffer is too small to hold the result,
a `ShortBufferException` is thrown. In this case, repeat this
call with a larger output buffer. Use
`https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)` to determine how big
the output buffer should be.
Upon finishing, this method resets this cipher object to the state
it was in when previously initialized via a call to `init`.
That is, the object is reset and available to encrypt or decrypt
(depending on the operation mode that was specified in the call to
`init`) more data.
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Note: this method should be copy-safe, which means the
`input` and `output` buffers can reference
the same byte array and no unprocessed input data is overwritten
when the result is copied into the output buffer.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| `inputOffset` | `int`: the offset in `input` where the input starts
|
| `inputLen` | `int`: the input length
|
| `output` | `byte`: the buffer for the result
|
| `outputOffset` | `int`: the offset in `output` where the result is stored
|
| Returns ||
|---|---|
| `int` | the number of bytes stored in `output`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/AEADBadTagException` | if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value |
| `https://developer.android.com/reference/javax/crypto/BadPaddingException` | if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
| `https://developer.android.com/reference/javax/crypto/ShortBufferException` | if the given output buffer is too small to hold the result |
### doFinal
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int doFinal (ByteBuffer input,
ByteBuffer output)
```
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
All `input.remaining()` bytes starting at
`input.position()` are processed.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
The result is stored in the output buffer.
Upon return, the input buffer's position will be equal
to its limit; its limit will not have changed. The output buffer's
position will have advanced by n, where n is the value returned
by this method; the output buffer's limit will not have changed.
If `output.remaining()` bytes are insufficient to
hold the result, a `ShortBufferException` is thrown.
In this case, repeat this call with a larger output buffer. Use
`https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)` to determine how big
the output buffer should be.
Upon finishing, this method resets this cipher object to the state
it was in when previously initialized via a call to `init`.
That is, the object is reset and available to encrypt or decrypt
(depending on the operation mode that was specified in the call to
`init`) more data.
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
Note: this method should be copy-safe, which means the
`input` and `output` buffers can reference
the same byte array and no unprocessed input data is overwritten
when the result is copied into the output buffer.
| Parameters ||
|---|---|
| `input` | `ByteBuffer`: the input ByteBuffer
|
| `output` | `ByteBuffer`: the output ByteBuffer
|
| Returns ||
|---|---|
| `int` | the number of bytes stored in `output`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if input and output are the same object |
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/java/nio/ReadOnlyBufferException` | if the output buffer is read-only |
| `https://developer.android.com/reference/javax/crypto/AEADBadTagException` | if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value |
| `https://developer.android.com/reference/javax/crypto/BadPaddingException` | if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
| `https://developer.android.com/reference/javax/crypto/ShortBufferException` | if there is insufficient space in the output buffer |
### doFinal
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final byte[] doFinal (byte[] input,
int inputOffset,
int inputLen)
```
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.
The first `inputLen` bytes in the `input`
buffer, starting at `inputOffset` inclusive, and any input
bytes that may have been buffered during a previous `update`
operation, are processed, with padding (if requested) being applied.
If an AEAD mode such as GCM/CCM is being used, the authentication
tag is appended in the case of encryption, or verified in the
case of decryption.
The result is stored in a new buffer.
Upon finishing, this method resets this cipher object to the state
it was in when previously initialized via a call to `init`.
That is, the object is reset and available to encrypt or decrypt
(depending on the operation mode that was specified in the call to
`init`) more data.
Note: if any exception is thrown, this cipher object may need to
be reset before it can be used again.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| `inputOffset` | `int`: the offset in `input` where the input starts
|
| `inputLen` | `int`: the input length
|
| Returns ||
|---|---|
| `byte[]` | the new buffer with the result
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/AEADBadTagException` | if this cipher is decrypting in an AEAD mode (such as GCM/CCM), and the received authentication tag does not match the calculated value |
| `https://developer.android.com/reference/javax/crypto/BadPaddingException` | if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size; or if this encryption algorithm is unable to process the input data provided. |
### getAlgorithm
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final String getAlgorithm ()
```
Returns the algorithm name of this `Cipher` object.
This is the same name that was specified in one of the
`getInstance` calls that created this `Cipher`
object..
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | the algorithm name of this `Cipher` object.
|
### getBlockSize
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int getBlockSize ()
```
Returns the block size (in bytes).
| Returns ||
|---|---|
| `int` | the block size (in bytes), or 0 if the underlying algorithm is not a block cipher
|
### getExemptionMechanism
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final ExemptionMechanism getExemptionMechanism ()
```
Returns the exemption mechanism object used with this cipher.
| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/ExemptionMechanism` | the exemption mechanism object used with this cipher, or null if this cipher does not use any exemption mechanism.
|
### getIV
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final byte[] getIV ()
```
Returns the initialization vector (IV) in a new buffer.
This is useful in the case where a random IV was created,
or in the context of password-based encryption or
decryption, where the IV is derived from a user-supplied password.
| Returns ||
|---|---|
| `byte[]` | the initialization vector in a new buffer, or null if the underlying algorithm does not use an IV, or if the IV has not yet been set.
|
### getInstance
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final Cipher getInstance (String transformation)
```
Returns a `Cipher` object that implements the specified
transformation.
This method traverses the list of registered security Providers,
starting with the most preferred Provider.
A new Cipher object encapsulating the
CipherSpi implementation from the first
Provider that supports the specified algorithm is returned.
Note that the list of registered providers may be retrieved via
the `https://developer.android.com/reference/java/security/Security#getProviders()` method.
| Parameters ||
|---|---|
| `transformation` | `String`: the name of the transformation, e.g., *DES/CBC/PKCS5Padding*. See the Cipher section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#Cipher) for information about standard transformation names.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/Cipher` | a cipher that implements the requested transformation.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if `transformation` is null, empty, in an invalid format, or if no Provider supports a CipherSpi implementation for the specified algorithm. |
| `https://developer.android.com/reference/javax/crypto/NoSuchPaddingException` | if `transformation` contains a padding scheme that is not available. |
**See also:**
- `https://developer.android.com/reference/java/security/Provider`
### getInstance
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final Cipher getInstance (String transformation,
String provider)
```
Returns a `Cipher` object that implements the specified
transformation.
A new Cipher object encapsulating the
CipherSpi implementation from the specified provider
is returned. The specified provider must be registered
in the security provider list.
Note that the list of registered providers may be retrieved via
the `https://developer.android.com/reference/java/security/Security#getProviders()` method.
| Parameters ||
|---|---|
| `transformation` | `String`: the name of the transformation, e.g., *DES/CBC/PKCS5Padding*. See the Cipher section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#Cipher) for information about standard transformation names.
|
| `provider` | `String`: the name of the provider.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/Cipher` | a cipher that implements the requested transformation.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `provider` is null or empty. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if `transformation` is null, empty, in an invalid format, or if a CipherSpi implementation for the specified algorithm is not available from the specified provider. |
| `https://developer.android.com/reference/java/security/NoSuchProviderException` | if the specified provider is not registered in the security provider list. |
| `https://developer.android.com/reference/javax/crypto/NoSuchPaddingException` | if `transformation` contains a padding scheme that is not available. |
**See also:**
- `https://developer.android.com/reference/java/security/Provider`
### getInstance
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final Cipher getInstance (String transformation,
Provider provider)
```
Returns a `Cipher` object that implements the specified
transformation.
A new Cipher object encapsulating the
CipherSpi implementation from the specified Provider
object is returned. Note that the specified Provider object
does not have to be registered in the provider list.
| Parameters ||
|---|---|
| `transformation` | `String`: the name of the transformation, e.g., *DES/CBC/PKCS5Padding*. See the Cipher section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#Cipher) for information about standard transformation names.
|
| `provider` | `Provider`: the provider.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/Cipher` | a cipher that implements the requested transformation.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `provider` is null. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if `transformation` is null, empty, in an invalid format, or if a CipherSpi implementation for the specified algorithm is not available from the specified Provider object. |
| `https://developer.android.com/reference/javax/crypto/NoSuchPaddingException` | if `transformation` contains a padding scheme that is not available. |
**See also:**
- `https://developer.android.com/reference/java/security/Provider`
### getMaxAllowedKeyLength
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final int getMaxAllowedKeyLength (String transformation)
```
Returns the maximum key length for the specified transformation
according to the installed JCE jurisdiction policy files. If
JCE unlimited strength jurisdiction policy files are installed,
Integer.MAX_VALUE will be returned.
For more information on default key size in JCE jurisdiction
policy files, please see Appendix E in the
[Java Cryptography Architecture Reference Guide](https://docs.oracle.com/javase/8/docs/technotes/guides/security/crypto/CryptoSpec.html#AppC).
| Parameters ||
|---|---|
| `transformation` | `String`: the cipher transformation.
|
| Returns ||
|---|---|
| `int` | the maximum key length in bits or Integer.MAX_VALUE.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/NullPointerException` | if `transformation` is null. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if `transformation` is not a valid transformation, i.e. in the form of "algorithm" or "algorithm/mode/padding". |
### getMaxAllowedParameterSpec
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final AlgorithmParameterSpec getMaxAllowedParameterSpec (String transformation)
```
Returns an AlgorithmParameterSpec object which contains
the maximum cipher parameter value according to the
jurisdiction policy file. If JCE unlimited strength jurisdiction
policy files are installed or there is no maximum limit on the
parameters for the specified transformation in the policy file,
null will be returned.
| Parameters ||
|---|---|
| `transformation` | `String`: the cipher transformation.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/security/spec/AlgorithmParameterSpec` | an AlgorithmParameterSpec which holds the maximum value or null.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/NullPointerException` | if `transformation` is null. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if `transformation` is not a valid transformation, i.e. in the form of "algorithm" or "algorithm/mode/padding". |
### getOutputSize
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int getOutputSize (int inputLen)
```
Returns the length in bytes that an output buffer would need to be in
order to hold the result of the next `update` or
`doFinal` operation, given the input length
`inputLen` (in bytes).
This call takes into account any unprocessed (buffered) data from a
previous `update` call, padding, and AEAD tagging.
The actual output length of the next `update` or
`doFinal` call may be smaller than the length returned by
this method.
| Parameters ||
|---|---|
| `inputLen` | `int`: the input length (in bytes)
|
| Returns ||
|---|---|
| `int` | the required output buffer size (in bytes)
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not yet been initialized) |
### getParameters
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final AlgorithmParameters getParameters ()
```
Returns the parameters used with this cipher.
The returned parameters may be the same that were used to initialize
this cipher, or may contain a combination of default and random
parameter values used by the underlying cipher implementation if this
cipher requires algorithm parameters but was not initialized with any.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/security/AlgorithmParameters` | the parameters used with this cipher, or null if this cipher does not use any parameters.
|
### getProvider
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Provider getProvider ()
```
Returns the provider of this `Cipher` object.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/security/Provider` | the provider of this `Cipher` object
|
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Key key,
AlgorithmParameters params)
```
Initializes this cipher with a key and a set of algorithm
parameters.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping or key unwrapping, depending
on the value of `opmode`.
If this cipher requires any algorithm parameters and
`params` is null, the underlying cipher implementation is
supposed to generate the required parameters itself (using
provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an
`InvalidAlgorithmParameterException` if it is being
initialized for decryption or key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them using the `https://developer.android.com/reference/java/security/SecureRandom`
implementation of the highest-priority
installed provider as the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness will be used.)
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `key` | `Key`: the encryption key
|
| `params` | `AlgorithmParameters`: the algorithm parameters
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidAlgorithmParameterException` | if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and `params` is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files). |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files). |
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Certificate certificate,
SecureRandom random)
```
Initializes this cipher with the public key from the given certificate
and
a source of randomness.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping
or key unwrapping, depending on
the value of `opmode`.
If the certificate is of type X.509 and has a *key usage*
extension field marked as critical, and the value of the *key usage*
extension field implies that the public key in
the certificate and its corresponding private key are not
supposed to be used for the operation represented by the value of
`opmode`,
an `InvalidKeyException`
is thrown.
If this cipher requires any algorithm parameters that cannot be
derived from the public key in the given `certificate`,
the underlying cipher
implementation is supposed to generate the required parameters itself
(using provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an
`InvalidKeyException` if it is being
initialized for decryption or key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them from `random`.
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `certificate` | `Certificate`: the certificate
|
| `random` | `SecureRandom`: the source of randomness
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the public key in the given certificate is inappropriate for initializing this cipher, or this cipher requires algorithm parameters that cannot be determined from the public key in the given certificate, or the keysize of the public key in the given certificate has a keysize that exceeds the maximum allowable keysize (as determined by the configured jurisdiction policy files). |
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Key key,
SecureRandom random)
```
Initializes this cipher with a key and a source of randomness.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping or key unwrapping, depending
on the value of `opmode`.
If this cipher requires any algorithm parameters that cannot be
derived from the given `key`, the underlying cipher
implementation is supposed to generate the required parameters itself
(using provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an
`InvalidKeyException` if it is being
initialized for decryption or key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them from `random`.
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `key` | `Key`: the encryption key
|
| `random` | `SecureRandom`: the source of randomness
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the given key is inappropriate for initializing this cipher, or requires algorithm parameters that cannot be determined from the given key, or if the given key has a keysize that exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files). |
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Key key,
AlgorithmParameterSpec params)
```
Initializes this cipher with a key and a set of algorithm
parameters.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping or key unwrapping, depending
on the value of `opmode`.
If this cipher requires any algorithm parameters and
`params` is null, the underlying cipher implementation is
supposed to generate the required parameters itself (using
provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an
`InvalidAlgorithmParameterException` if it is being
initialized for decryption or key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them using the `https://developer.android.com/reference/java/security/SecureRandom`
implementation of the highest-priority
installed provider as the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness will be used.)
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `key` | `Key`: the encryption key
|
| `params` | `AlgorithmParameterSpec`: the algorithm parameters
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidAlgorithmParameterException` | if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and `params` is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files). |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files). |
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Key key)
```
Initializes this cipher with a key.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping or key unwrapping, depending
on the value of `opmode`.
If this cipher requires any algorithm parameters that cannot be
derived from the given `key`, the underlying cipher
implementation is supposed to generate the required parameters itself
(using provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an
`InvalidKeyException` if it is being
initialized for decryption or key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them using the `https://developer.android.com/reference/java/security/SecureRandom`
implementation of the highest-priority
installed provider as the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness will be used.)
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `key` | `Key`: the key
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the given key is inappropriate for initializing this cipher, or requires algorithm parameters that cannot be determined from the given key, or if the given key has a keysize that exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files). |
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Key key,
AlgorithmParameterSpec params,
SecureRandom random)
```
Initializes this cipher with a key, a set of algorithm
parameters, and a source of randomness.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping or key unwrapping, depending
on the value of `opmode`.
If this cipher requires any algorithm parameters and
`params` is null, the underlying cipher implementation is
supposed to generate the required parameters itself (using
provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an
`InvalidAlgorithmParameterException` if it is being
initialized for decryption or key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them from `random`.
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `key` | `Key`: the encryption key
|
| `params` | `AlgorithmParameterSpec`: the algorithm parameters
|
| `random` | `SecureRandom`: the source of randomness
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidAlgorithmParameterException` | if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and `params` is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files). |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files). |
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Certificate certificate)
```
Initializes this cipher with the public key from the given certificate.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping or key unwrapping, depending
on the value of `opmode`.
If the certificate is of type X.509 and has a *key usage*
extension field marked as critical, and the value of the *key usage*
extension field implies that the public key in
the certificate and its corresponding private key are not
supposed to be used for the operation represented by the value
of `opmode`,
an `InvalidKeyException`
is thrown.
If this cipher requires any algorithm parameters that cannot be
derived from the public key in the given certificate, the underlying
cipher
implementation is supposed to generate the required parameters itself
(using provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an `
InvalidKeyException` if it is being initialized for decryption or
key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them using the
`SecureRandom`
implementation of the highest-priority
installed provider as the source of randomness.
(If none of the installed providers supply an implementation of
SecureRandom, a system-provided source of randomness will be used.)
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `certificate` | `Certificate`: the certificate
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the public key in the given certificate is inappropriate for initializing this cipher, or this cipher requires algorithm parameters that cannot be determined from the public key in the given certificate, or the keysize of the public key in the given certificate has a keysize that exceeds the maximum allowable keysize (as determined by the configured jurisdiction policy files). |
### init
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void init (int opmode,
Key key,
AlgorithmParameters params,
SecureRandom random)
```
Initializes this cipher with a key, a set of algorithm
parameters, and a source of randomness.
The cipher is initialized for one of the following four operations:
encryption, decryption, key wrapping or key unwrapping, depending
on the value of `opmode`.
If this cipher requires any algorithm parameters and
`params` is null, the underlying cipher implementation is
supposed to generate the required parameters itself (using
provider-specific default or random values) if it is being
initialized for encryption or key wrapping, and raise an
`InvalidAlgorithmParameterException` if it is being
initialized for decryption or key unwrapping.
The generated parameters can be retrieved using
`https://developer.android.com/reference/javax/crypto/Cipher#getParameters()` or
`https://developer.android.com/reference/javax/crypto/Cipher#getIV()` (if the parameter is an IV).
If this cipher requires algorithm parameters that cannot be
derived from the input parameters, and there are no reasonable
provider-specific default values, initialization will
necessarily fail.
If this cipher (including its underlying feedback or padding scheme)
requires any random bytes (e.g., for parameter generation), it will get
them from `random`.
Note that when a Cipher object is initialized, it loses all
previously-acquired state. In other words, initializing a Cipher is
equivalent to creating a new instance of that Cipher and initializing
it.
| Parameters ||
|---|---|
| `opmode` | `int`: the operation mode of this cipher (this is one of the following: `ENCRYPT_MODE`, `DECRYPT_MODE`, `WRAP_MODE` or `UNWRAP_MODE`)
|
| `key` | `Key`: the encryption key
|
| `params` | `AlgorithmParameters`: the algorithm parameters
|
| `random` | `SecureRandom`: the source of randomness
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if (@code opmode} is `WRAP_MODE` or `UNWRAP_MODE` but the mode is not implemented by the underlying `CipherSpi`. |
| `https://developer.android.com/reference/java/security/InvalidAlgorithmParameterException` | if the given algorithm parameters are inappropriate for this cipher, or this cipher requires algorithm parameters and `params` is null, or the given algorithm parameters imply a cryptographic strength that would exceed the legal limits (as determined from the configured jurisdiction policy files). |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the given key is inappropriate for initializing this cipher, or its keysize exceeds the maximum allowable keysize (as determined from the configured jurisdiction policy files). |
### unwrap
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final Key unwrap (byte[] wrappedKey,
String wrappedKeyAlgorithm,
int wrappedKeyType)
```
Unwrap a previously wrapped key.
| Parameters ||
|---|---|
| `wrappedKey` | `byte`: the key to be unwrapped.
|
| `wrappedKeyAlgorithm` | `String`: the algorithm associated with the wrapped key.
|
| `wrappedKeyType` | `int`: the type of the wrapped key. This must be one of `SECRET_KEY`, `PRIVATE_KEY`, or `PUBLIC_KEY`.
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/security/Key` | the unwrapped key.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized). |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the corresponding method in the `CipherSpi` is not supported. |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if `wrappedKey` does not represent a wrapped key of type `wrappedKeyType` for the `wrappedKeyAlgorithm`. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if no installed providers can create keys of type `wrappedKeyType` for the `wrappedKeyAlgorithm`. |
### update
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final byte[] update (byte[] input)
```
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The bytes in the `input` buffer are processed, and the
result is stored in a new buffer.
If `input` has a length of zero, this method returns
`null`.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| Returns ||
|---|---|
| `byte[]` | the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
### update
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int update (byte[] input,
int inputOffset,
int inputLen,
byte[] output)
```
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The first `inputLen` bytes in the `input`
buffer, starting at `inputOffset` inclusive, are processed,
and the result is stored in the `output` buffer.
If the `output` buffer is too small to hold the result,
a `ShortBufferException` is thrown. In this case, repeat this
call with a larger output buffer. Use
`https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)` to determine how big
the output buffer should be.
If `inputLen` is zero, this method returns
a length of zero.
Note: this method should be copy-safe, which means the
`input` and `output` buffers can reference
the same byte array and no unprocessed input data is overwritten
when the result is copied into the output buffer.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| `inputOffset` | `int`: the offset in `input` where the input starts
|
| `inputLen` | `int`: the input length
|
| `output` | `byte`: the buffer for the result
|
| Returns ||
|---|---|
| `int` | the number of bytes stored in `output`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/ShortBufferException` | if the given output buffer is too small to hold the result |
### update
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final byte[] update (byte[] input,
int inputOffset,
int inputLen)
```
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The first `inputLen` bytes in the `input`
buffer, starting at `inputOffset` inclusive, are processed,
and the result is stored in a new buffer.
If `inputLen` is zero, this method returns
`null`.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| `inputOffset` | `int`: the offset in `input` where the input starts
|
| `inputLen` | `int`: the input length
|
| Returns ||
|---|---|
| `byte[]` | the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
### update
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int update (ByteBuffer input,
ByteBuffer output)
```
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
All `input.remaining()` bytes starting at
`input.position()` are processed. The result is stored
in the output buffer.
Upon return, the input buffer's position will be equal
to its limit; its limit will not have changed. The output buffer's
position will have advanced by n, where n is the value returned
by this method; the output buffer's limit will not have changed.
If `output.remaining()` bytes are insufficient to
hold the result, a `ShortBufferException` is thrown.
In this case, repeat this call with a larger output buffer. Use
`https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)` to determine how big
the output buffer should be.
Note: this method should be copy-safe, which means the
`input` and `output` buffers can reference
the same block of memory and no unprocessed input data is overwritten
when the result is copied into the output buffer.
| Parameters ||
|---|---|
| `input` | `ByteBuffer`: the input ByteBuffer
|
| `output` | `ByteBuffer`: the output ByteByffer
|
| Returns ||
|---|---|
| `int` | the number of bytes stored in `output`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if input and output are the same object |
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/java/nio/ReadOnlyBufferException` | if the output buffer is read-only |
| `https://developer.android.com/reference/javax/crypto/ShortBufferException` | if there is insufficient space in the output buffer |
### update
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final int update (byte[] input,
int inputOffset,
int inputLen,
byte[] output,
int outputOffset)
```
Continues a multiple-part encryption or decryption operation
(depending on how this cipher was initialized), processing another data
part.
The first `inputLen` bytes in the `input`
buffer, starting at `inputOffset` inclusive, are processed,
and the result is stored in the `output` buffer, starting at
`outputOffset` inclusive.
If the `output` buffer is too small to hold the result,
a `ShortBufferException` is thrown. In this case, repeat this
call with a larger output buffer. Use
`https://developer.android.com/reference/javax/crypto/Cipher#getOutputSize(int)` to determine how big
the output buffer should be.
If `inputLen` is zero, this method returns
a length of zero.
Note: this method should be copy-safe, which means the
`input` and `output` buffers can reference
the same byte array and no unprocessed input data is overwritten
when the result is copied into the output buffer.
| Parameters ||
|---|---|
| `input` | `byte`: the input buffer
|
| `inputOffset` | `int`: the offset in `input` where the input starts
|
| `inputLen` | `int`: the input length
|
| `output` | `byte`: the buffer for the result
|
| `outputOffset` | `int`: the offset in `output` where the result is stored
|
| Returns ||
|---|---|
| `int` | the number of bytes stored in `output`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized) |
| `https://developer.android.com/reference/javax/crypto/ShortBufferException` | if the given output buffer is too small to hold the result |
### updateAAD
Added in [API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void updateAAD (byte[] src,
int offset,
int len)
```
Continues a multi-part update of the Additional Authentication
Data (AAD), using a subset of the provided buffer.
Calls to this method provide AAD to the cipher when operating in
modes such as AEAD (GCM/CCM). If this cipher is operating in
either GCM or CCM mode, all AAD must be supplied before beginning
operations on the ciphertext (via the `update` and `doFinal` methods).
| Parameters ||
|---|---|
| `src` | `byte`: the buffer containing the AAD
|
| `offset` | `int`: the offset in `src` where the AAD input starts
|
| `len` | `int`: the number of AAD bytes
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `src` byte array is null, or the `offset` or `length` is less than 0, or the sum of the `offset` and `len` is greater than the length of the `src` byte array |
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the `update` methods has already been called for the active encryption/decryption operation |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the corresponding method in the `CipherSpi` has not been overridden by an implementation |
### updateAAD
Added in [API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void updateAAD (ByteBuffer src)
```
Continues a multi-part update of the Additional Authentication
Data (AAD).
Calls to this method provide AAD to the cipher when operating in
modes such as AEAD (GCM/CCM). If this cipher is operating in
either GCM or CCM mode, all AAD must be supplied before beginning
operations on the ciphertext (via the `update` and `doFinal` methods).
All `src.remaining()` bytes starting at
`src.position()` are processed.
Upon return, the input buffer's position will be equal
to its limit; its limit will not have changed.
| Parameters ||
|---|---|
| `src` | `ByteBuffer`: the buffer containing the AAD
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `src ByteBuffer` is null |
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the `update` methods has already been called for the active encryption/decryption operation |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the corresponding method in the `CipherSpi` has not been overridden by an implementation |
### updateAAD
Added in [API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final void updateAAD (byte[] src)
```
Continues a multi-part update of the Additional Authentication
Data (AAD).
Calls to this method provide AAD to the cipher when operating in
modes such as AEAD (GCM/CCM). If this cipher is operating in
either GCM or CCM mode, all AAD must be supplied before beginning
operations on the ciphertext (via the `update` and `doFinal` methods).
| Parameters ||
|---|---|
| `src` | `byte`: the buffer containing the Additional Authentication Data
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `src` byte array is null |
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized), does not accept AAD, or if operating in either GCM or CCM mode and one of the `update` methods has already been called for the active encryption/decryption operation |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the corresponding method in the `CipherSpi` has not been overridden by an implementation |
### wrap
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public final byte[] wrap (Key key)
```
Wrap a key.
| Parameters ||
|---|---|
| `key` | `Key`: the key to be wrapped.
|
| Returns ||
|---|---|
| `byte[]` | the wrapped key.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalStateException` | if this cipher is in a wrong state (e.g., has not been initialized). |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the corresponding method in the `CipherSpi` is not supported. |
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if it is impossible or unsafe to wrap the key with this cipher (e.g., a hardware protected key is being passed to a software-only cipher). |
| `https://developer.android.com/reference/javax/crypto/IllegalBlockSizeException` | if this cipher is a block cipher, no padding has been requested, and the length of the encoding of the key to be wrapped is not a multiple of the block size. |