Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Protected Ctors](https://developer.android.com/reference/javax/crypto/SecretKeyFactory#proctors) \| [Methods](https://developer.android.com/reference/javax/crypto/SecretKeyFactory#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/javax/crypto/SecretKeyFactory#inhmethods)

# SecretKeyFactory

` public class SecretKeyFactory `   
` extends https://developer.android.com/reference/java/lang/Object ` ` `

|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | javax.crypto.SecretKeyFactory |

<br />

*** ** * ** ***

This class represents a factory for secret keys.

Key factories are used to convert *keys* (opaque cryptographic keys of type `Key`) into *key specifications* (transparent representations of the underlying key material), and vice versa. Secret key factories operate only on secret (symmetric) keys.

Key factories are bi-directional, i.e., they allow to build an opaque key object from a given key specification (key material), or to retrieve the underlying key material of a key object in a suitable format.

Application developers should refer to their provider's documentation to find out which key specifications are supported by the `https://developer.android.com/reference/javax/crypto/SecretKeyFactory#generateSecret(java.security.spec.KeySpec)` and `https://developer.android.com/reference/javax/crypto/SecretKeyFactory#getKeySpec(javax.crypto.SecretKey,%20java.lang.Class<?>)` methods. For example, the DES secret-key factory supplied by the "SunJCE" provider supports `DESKeySpec` as a transparent representation of DES keys, and that provider's secret-key factory for Triple DES keys supports `DESedeKeySpec` as a transparent representation of Triple DES keys.

Android provides the following `SecretKeyFactory` algorithms:

| Algorithm | Supported API Levels |
|---|---|
| AES | 23+ |
| DES | 1+ |
| DESede | 1+ |
| HmacSHA1 | 23+ |
| HmacSHA224 | 23+ |
| HmacSHA256 | 23+ |
| HmacSHA384 | 23+ |
| HmacSHA512 | 23+ |
| PBEwithHmacSHA1 | 1+ |
| PBEwithHmacSHA1AndAES_128 | 26+ |
| PBEwithHmacSHA1AndAES_256 | 26+ |
| PBEwithHmacSHA224AndAES_128 | 26+ |
| PBEwithHmacSHA224AndAES_256 | 26+ |
| PBEwithHmacSHA256AndAES_128 | 26+ |
| PBEwithHmacSHA256AndAES_256 | 26+ |
| PBEwithHmacSHA384AndAES_128 | 26+ |
| PBEwithHmacSHA384AndAES_256 | 26+ |
| PBEwithHmacSHA512AndAES_128 | 26+ |
| PBEwithHmacSHA512AndAES_256 | 26+ |
| PBEwithMD5AND128BITAES-CBC-OPENSSL | 1+ |
| PBEwithMD5AND192BITAES-CBC-OPENSSL | 1+ |
| PBEwithMD5AND256BITAES-CBC-OPENSSL | 1+ |
| PBEwithMD5ANDDES | 1+ |
| PBEwithMD5ANDRC2 | 1+ |
| PBEwithSHA1ANDDES | 1+ |
| PBEwithSHA1ANDRC2 | 1+ |
| PBEwithSHA256AND128BITAES-CBC-BC | 1+ |
| PBEwithSHA256AND192BITAES-CBC-BC | 1+ |
| PBEwithSHA256AND256BITAES-CBC-BC | 1+ |
| PBEwithSHAAND128BITAES-CBC-BC | 1+ |
| PBEwithSHAAND128BITRC2-CBC | 10+ |
| PBEwithSHAAND128BITRC4 | 10+ |
| PBEwithSHAAND192BITAES-CBC-BC | 1+ |
| PBEwithSHAAND2-KEYTRIPLEDES-CBC | 1+ |
| PBEwithSHAAND256BITAES-CBC-BC | 1+ |
| PBEwithSHAAND3-KEYTRIPLEDES-CBC | 1+ |
| PBEwithSHAAND40BITRC2-CBC | 1+ |
| PBEwithSHAAND40BITRC4 | 10+ |
| PBEwithSHAANDTWOFISH-CBC | 10+ |
| PBKDF2withHmacSHA1 | 10+ |
| PBKDF2withHmacSHA1And8BIT | 19+ |
| PBKDF2withHmacSHA224 | 26+ |
| PBKDF2withHmacSHA256 | 26+ |
| PBKDF2withHmacSHA384 | 26+ |
| PBKDF2withHmacSHA512 | 26+ |

These algorithms are described in the [SecretKeyFactory section](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#SecretKeyFactory) of the Java Cryptography Architecture Standard Algorithm Name Documentation.

<br />

**See also:**

- `https://developer.android.com/reference/javax/crypto/SecretKey`
- `https://developer.android.com/reference/javax/crypto/spec/DESKeySpec`
- `https://developer.android.com/reference/javax/crypto/spec/DESedeKeySpec`
- `https://developer.android.com/reference/javax/crypto/spec/PBEKeySpec`

## Summary

| ### Protected constructors ||
|---|---|
| ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#SecretKeyFactory(javax.crypto.SecretKeyFactorySpi,%20java.security.Provider,%20java.lang.String)(https://developer.android.com/reference/javax/crypto/SecretKeyFactorySpi keyFacSpi, https://developer.android.com/reference/java/security/Provider provider, https://developer.android.com/reference/java/lang/String algorithm) ` Creates a SecretKeyFactory object. |

| ### Public methods ||
|---|---|
| ` final https://developer.android.com/reference/javax/crypto/SecretKey` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#generateSecret(java.security.spec.KeySpec)(https://developer.android.com/reference/java/security/spec/KeySpec keySpec) ` Generates a `SecretKey` object from the provided key specification (key material). |
| ` final https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#getAlgorithm()() ` Returns the algorithm name of this `SecretKeyFactory` object. |
| ` static final https://developer.android.com/reference/javax/crypto/SecretKeyFactory` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#getInstance(java.lang.String)(https://developer.android.com/reference/java/lang/String algorithm) ` Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm. |
| ` static final https://developer.android.com/reference/javax/crypto/SecretKeyFactory` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#getInstance(java.lang.String,%20java.lang.String)(https://developer.android.com/reference/java/lang/String algorithm, https://developer.android.com/reference/java/lang/String provider) ` Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm. |
| ` static final https://developer.android.com/reference/javax/crypto/SecretKeyFactory` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#getInstance(java.lang.String,%20java.security.Provider)(https://developer.android.com/reference/java/lang/String algorithm, https://developer.android.com/reference/java/security/Provider provider) ` Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm. |
| ` final https://developer.android.com/reference/java/security/spec/KeySpec` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#getKeySpec(javax.crypto.SecretKey,%20java.lang.Class<?>)(https://developer.android.com/reference/javax/crypto/SecretKey key, https://developer.android.com/reference/java/lang/Class<?> keySpec) ` Returns a specification (key material) of the given key object in the requested format. |
| ` final https://developer.android.com/reference/java/security/Provider` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#getProvider()() ` Returns the provider of this `SecretKeyFactory` object. |
| ` final https://developer.android.com/reference/javax/crypto/SecretKey` | ` https://developer.android.com/reference/javax/crypto/SecretKeyFactory#translateKey(javax.crypto.SecretKey)(https://developer.android.com/reference/javax/crypto/SecretKey key) ` Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this secret-key factory. |

### 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*.

## Protected constructors

### SecretKeyFactory

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
protected SecretKeyFactory (SecretKeyFactorySpi keyFacSpi, 
                Provider provider, 
                String algorithm)
```

Creates a SecretKeyFactory object.

<br />

| Parameters ||
|---|---|
| `keyFacSpi` | `SecretKeyFactorySpi`: the delegate <br /> |
| `provider` | `Provider`: the provider <br /> |
| `algorithm` | `String`: the secret-key algorithm <br /> |

## Public methods

### generateSecret

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public final SecretKey generateSecret (KeySpec keySpec)
```

Generates a `SecretKey` object from the provided key specification (key material).

<br />

| Parameters ||
|---|---|
| `keySpec` | `KeySpec`: the specification (key material) of the secret key <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/SecretKey` | the secret key <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/security/spec/InvalidKeySpecException` | if the given key specification is inappropriate for this secret-key factory to produce a secret key. |

### 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 `SecretKeyFactory` object.

This is the same name that was specified in one of the `getInstance` calls that created this `SecretKeyFactory` object.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | the algorithm name of this `SecretKeyFactory` object. <br /> |

### getInstance

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final SecretKeyFactory getInstance (String algorithm)
```

Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi 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.

<br />

| Parameters ||
|---|---|
| `algorithm` | `String`: the standard name of the requested secret-key algorithm. See the SecretKeyFactory section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#SecretKeyFactory) for information about standard algorithm names. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/SecretKeyFactory` | the new `SecretKeyFactory` object. <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified algorithm is null. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if no Provider supports a SecretKeyFactorySpi implementation for the specified algorithm. |

**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 SecretKeyFactory getInstance (String algorithm, 
                String provider)
```

Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm.

A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi 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.

<br />

| Parameters ||
|---|---|
| `algorithm` | `String`: the standard name of the requested secret-key algorithm. See the SecretKeyFactory section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#SecretKeyFactory) for information about standard algorithm names. <br /> |
| `provider` | `String`: the name of the provider. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/SecretKeyFactory` | the new `SecretKeyFactory` object. <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `provider` is null or empty. |
| `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified algorithm is null. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if a SecretKeyFactorySpi 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. |

**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 SecretKeyFactory getInstance (String algorithm, 
                Provider provider)
```

Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm.

A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.

<br />

| Parameters ||
|---|---|
| `algorithm` | `String`: the standard name of the requested secret-key algorithm. See the SecretKeyFactory section in the [Java Cryptography Architecture Standard Algorithm Name Documentation](https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#SecretKeyFactory) for information about standard algorithm names. <br /> |
| `provider` | `Provider`: the provider. <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/SecretKeyFactory` | the new `SecretKeyFactory` object. <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `provider` is null. |
| `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified algorithm is null. |
| `https://developer.android.com/reference/java/security/NoSuchAlgorithmException` | if a SecretKeyFactorySpi implementation for the specified algorithm is not available from the specified Provider object. |

**See also:**

- `https://developer.android.com/reference/java/security/Provider`

### getKeySpec

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public final KeySpec getKeySpec (SecretKey key, 
                Class<?> keySpec)
```

Returns a specification (key material) of the given key object in the requested format.

<br />

| Parameters ||
|---|---|
| `key` | `SecretKey`: the key <br /> |
| `keySpec` | `Class`: the requested format in which the key material shall be returned <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/security/spec/KeySpec` | the underlying key specification (key material) in the requested format <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/security/spec/InvalidKeySpecException` | if the requested key specification is inappropriate for the given key (e.g., the algorithms associated with `key` and `keySpec` do not match, or `key` references a key on a cryptographic hardware device whereas `keySpec` is the specification of a software-based key), or the given key cannot be dealt with (e.g., the given key has an algorithm or format not supported by this secret-key factory). |

### 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 `SecretKeyFactory` object.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/security/Provider` | the provider of this `SecretKeyFactory` object <br /> |

### translateKey

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public final SecretKey translateKey (SecretKey key)
```

Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this secret-key factory.

<br />

| Parameters ||
|---|---|
| `key` | `SecretKey`: the key whose provider is unknown or untrusted <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/javax/crypto/SecretKey` | the translated key <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/security/InvalidKeyException` | if the given key cannot be processed by this secret-key factory. |