# CipherInputStream
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
Summary:[Inherited Fields](https://developer.android.com/reference/javax/crypto/CipherInputStream#inhfields)\|[Ctors](https://developer.android.com/reference/javax/crypto/CipherInputStream#pubctors)\|[Protected Ctors](https://developer.android.com/reference/javax/crypto/CipherInputStream#proctors)\|[Methods](https://developer.android.com/reference/javax/crypto/CipherInputStream#pubmethods)\|[Inherited Methods](https://developer.android.com/reference/javax/crypto/CipherInputStream#inhmethods)
# CipherInputStream
`
public
class
CipherInputStream
`
`
``
``
extends `[FilterInputStream](https://developer.android.com/reference/java/io/FilterInputStream)`
``
`
|---|---|---|--------------------------------|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||||
| ↳ | [java.io.InputStream](https://developer.android.com/reference/java/io/InputStream) |||
| | ↳ | [java.io.FilterInputStream](https://developer.android.com/reference/java/io/FilterInputStream) ||
| | | ↳ | javax.crypto.CipherInputStream |
*** ** * ** ***
A CipherInputStream is composed of an InputStream and a Cipher so that read() methods return data that are read in from the underlying InputStream but have been additionally processed by the Cipher. The Cipher must be fully initialized before being used by a CipherInputStream.
For example, if the Cipher is initialized for decryption, the CipherInputStream will attempt to read in data and decrypt them, before returning the decrypted data.
This class adheres strictly to the semantics, especially the failure semantics, of its ancestor classes java.io.FilterInputStream and java.io.InputStream. This class has exactly those methods specified in its ancestor classes, and overrides them all. Moreover, this class catches all exceptions that are not thrown by its ancestor classes. In particular, the`skip`method skips, and the`available`method counts only data that have been processed by the encapsulated Cipher.
It is crucial for a programmer using this class not to use methods that are not defined or overriden in this class (such as a new method or constructor that is later added to one of the super classes), because the design and implementation of those methods are unlikely to have considered security impact with regard to CipherInputStream.
**See also:**
- [InputStream](https://developer.android.com/reference/java/io/InputStream)
- [FilterInputStream](https://developer.android.com/reference/java/io/FilterInputStream)
- [Cipher](https://developer.android.com/reference/javax/crypto/Cipher)
- [CipherOutputStream](https://developer.android.com/reference/javax/crypto/CipherOutputStream)
## Summary
| ### Inherited fields |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| From class[java.io.FilterInputStream](https://developer.android.com/reference/java/io/FilterInputStream) |-----------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------| | ` protected `[InputStream](https://developer.android.com/reference/java/io/InputStream) | [in](https://developer.android.com/reference/java/io/FilterInputStream#in) The input stream to be filtered. | |
| ### Public constructors ||
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|
| ` `[CipherInputStream](https://developer.android.com/reference/javax/crypto/CipherInputStream#CipherInputStream(java.io.InputStream,%20javax.crypto.Cipher))`(`[InputStream](https://developer.android.com/reference/java/io/InputStream)` is, `[Cipher](https://developer.android.com/reference/javax/crypto/Cipher)` c) ` Constructs a CipherInputStream from an InputStream and a Cipher. |
| ### Protected constructors ||
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|
| ` `[CipherInputStream](https://developer.android.com/reference/javax/crypto/CipherInputStream#CipherInputStream(java.io.InputStream))`(`[InputStream](https://developer.android.com/reference/java/io/InputStream)` is) ` Constructs a CipherInputStream from an InputStream without specifying a Cipher. |
| ### Public methods ||
|------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ` int` | ` `[available](https://developer.android.com/reference/javax/crypto/CipherInputStream#available())`() ` Returns the number of bytes that can be read from this input stream without blocking. |
| ` void` | ` `[close](https://developer.android.com/reference/javax/crypto/CipherInputStream#close())`() ` Closes this input stream and releases any system resources associated with the stream. |
| ` boolean` | ` `[markSupported](https://developer.android.com/reference/javax/crypto/CipherInputStream#markSupported())`() ` Tests if this input stream supports the`mark`and`reset`methods, which it does not. |
| ` int` | ` `[read](https://developer.android.com/reference/javax/crypto/CipherInputStream#read())`() ` Reads the next byte of data from this input stream. |
| ` int` | ` `[read](https://developer.android.com/reference/javax/crypto/CipherInputStream#read(byte[],%20int,%20int))`(byte[] b, int off, int len) ` Reads up to`len`bytes of data from this input stream into an array of bytes. |
| ` int` | ` `[read](https://developer.android.com/reference/javax/crypto/CipherInputStream#read(byte[]))`(byte[] b) ` Reads up to`b.length`bytes of data from this input stream into an array of bytes. |
| ` long` | ` `[skip](https://developer.android.com/reference/javax/crypto/CipherInputStream#skip(long))`(long n) ` Skips`n`bytes of input from the bytes that can be read from this input stream without blocking. |
| ### Inherited methods |
|-----------------------|---|
| From class` `[java.io.FilterInputStream](https://developer.android.com/reference/java/io/FilterInputStream)` ` |------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` int` | ` `[available](https://developer.android.com/reference/java/io/FilterInputStream#available())`() ` Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. | | ` void` | ` `[close](https://developer.android.com/reference/java/io/FilterInputStream#close())`() ` Closes this input stream and releases any system resources associated with the stream. | | ` void` | ` `[mark](https://developer.android.com/reference/java/io/FilterInputStream#mark(int))`(int readlimit) ` Marks the current position in this input stream. | | ` boolean` | ` `[markSupported](https://developer.android.com/reference/java/io/FilterInputStream#markSupported())`() ` Tests if this input stream supports the`mark`and`reset`methods. | | ` int` | ` `[read](https://developer.android.com/reference/java/io/FilterInputStream#read())`() ` Reads the next byte of data from this input stream. | | ` int` | ` `[read](https://developer.android.com/reference/java/io/FilterInputStream#read(byte[],%20int,%20int))`(byte[] b, int off, int len) ` Reads up to`len`bytes of data from this input stream into an array of bytes. | | ` int` | ` `[read](https://developer.android.com/reference/java/io/FilterInputStream#read(byte[]))`(byte[] b) ` Reads up to`b.length`bytes of data from this input stream into an array of bytes. | | ` void` | ` `[reset](https://developer.android.com/reference/java/io/FilterInputStream#reset())`() ` Repositions this stream to the position at the time the`mark`method was last called on this input stream. | | ` long` | ` `[skip](https://developer.android.com/reference/java/io/FilterInputStream#skip(long))`(long n) ` Skips over and discards`n`bytes of data from the input stream. | ||
| From class` `[java.io.InputStream](https://developer.android.com/reference/java/io/InputStream)` ` |--------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` int` | ` `[available](https://developer.android.com/reference/java/io/InputStream#available())`() ` Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. | | ` void` | ` `[close](https://developer.android.com/reference/java/io/InputStream#close())`() ` Closes this input stream and releases any system resources associated with the stream. | | ` void` | ` `[mark](https://developer.android.com/reference/java/io/InputStream#mark(int))`(int readlimit) ` Marks the current position in this input stream. | | ` boolean` | ` `[markSupported](https://developer.android.com/reference/java/io/InputStream#markSupported())`() ` Tests if this input stream supports the`mark`and`reset`methods. | | ` static `[InputStream](https://developer.android.com/reference/java/io/InputStream) | ` `[nullInputStream](https://developer.android.com/reference/java/io/InputStream#nullInputStream())`() ` Returns a new`InputStream`that reads no bytes. | | ` int` | ` `[read](https://developer.android.com/reference/java/io/InputStream#read(byte[]))`(byte[] b) ` Reads some number of bytes from the input stream and stores them into the buffer array`b`. | | ` abstract int` | ` `[read](https://developer.android.com/reference/java/io/InputStream#read())`() ` Reads the next byte of data from the input stream. | | ` int` | ` `[read](https://developer.android.com/reference/java/io/InputStream#read(byte[],%20int,%20int))`(byte[] b, int off, int len) ` Reads up to`len`bytes of data from the input stream into an array of bytes. | | ` byte[]` | ` `[readAllBytes](https://developer.android.com/reference/java/io/InputStream#readAllBytes())`() ` Reads all remaining bytes from the input stream. | | ` int` | ` `[readNBytes](https://developer.android.com/reference/java/io/InputStream#readNBytes(byte[],%20int,%20int))`(byte[] b, int off, int len) ` Reads the requested number of bytes from the input stream into the given byte array. | | ` byte[]` | ` `[readNBytes](https://developer.android.com/reference/java/io/InputStream#readNBytes(int))`(int len) ` Reads up to a specified number of bytes from the input stream. | | ` void` | ` `[reset](https://developer.android.com/reference/java/io/InputStream#reset())`() ` Repositions this stream to the position at the time the`mark`method was last called on this input stream. | | ` long` | ` `[skip](https://developer.android.com/reference/java/io/InputStream#skip(long))`(long n) ` Skips over and discards`n`bytes of data from this input stream. | | ` void` | ` `[skipNBytes](https://developer.android.com/reference/java/io/InputStream#skipNBytes(long))`(long n) ` Skips over and discards exactly`n`bytes of data from this input stream. | | ` long` | ` `[transferTo](https://developer.android.com/reference/java/io/InputStream#transferTo(java.io.OutputStream))`(`[OutputStream](https://developer.android.com/reference/java/io/OutputStream)` out) ` Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read. | ||
| From class` `[java.lang.Object](https://developer.android.com/reference/java/lang/Object)` ` |--------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` `[Object](https://developer.android.com/reference/java/lang/Object) | ` `[clone](https://developer.android.com/reference/java/lang/Object#clone())`() ` Creates and returns a copy of this object. | | ` boolean` | ` `[equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` `[finalize](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 `[Class](https://developer.android.com/reference/java/lang/Class)`` | ` `[getClass](https://developer.android.com/reference/java/lang/Object#getClass())`() ` Returns the runtime class of this`Object`. | | ` int` | ` `[hashCode](https://developer.android.com/reference/java/lang/Object#hashCode())`() ` Returns a hash code value for the object. | | ` final void` | ` `[notify](https://developer.android.com/reference/java/lang/Object#notify())`() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` `[notifyAll](https://developer.android.com/reference/java/lang/Object#notifyAll())`() ` Wakes up all threads that are waiting on this object's monitor. | | ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/java/lang/Object#toString())`() ` Returns a string representation of the object. | | ` final void` | ` `[wait](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` | ` `[wait](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` | ` `[wait](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*. | ||
| From interface` `[java.io.Closeable](https://developer.android.com/reference/java/io/Closeable)` ` |------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` abstract void` | ` `[close](https://developer.android.com/reference/java/io/Closeable#close())`() ` Closes this stream and releases any system resources associated with it. | ||
| From interface` `[java.lang.AutoCloseable](https://developer.android.com/reference/java/lang/AutoCloseable)` ` |------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------| | ` abstract void` | ` `[close](https://developer.android.com/reference/java/lang/AutoCloseable#close())`() ` Closes this resource, relinquishing any underlying resources. | ||
## Public constructors
### CipherInputStream
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public CipherInputStream (InputStream is,
Cipher c)
```
Constructs a CipherInputStream from an InputStream and a Cipher.
Note: if the specified input stream or cipher is null, a NullPointerException may be thrown later when they are used.
| Parameters ||
|------|--------------------------------------------------------|
| `is` | `InputStream`: the to-be-processed input stream
|
| `c` | `Cipher`: an initialized Cipher object
|
## Protected constructors
### CipherInputStream
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
protected CipherInputStream (InputStream is)
```
Constructs a CipherInputStream from an InputStream without specifying a Cipher. This has the effect of constructing a CipherInputStream using a NullCipher.
Note: if the specified input stream is null, a NullPointerException may be thrown later when it is used.
| Parameters ||
|------|--------------------------------------------------------|
| `is` | `InputStream`: the to-be-processed input stream
|
## Public methods
### available
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int available ()
```
Returns the number of bytes that can be read from this input stream without blocking. The`available`method of`InputStream`returns`0`. This method**should**be overridden by subclasses.
| Returns ||
|-------|--------------------------------------------------------------------------------------|
| `int` | the number of bytes that can be read from this input stream without blocking.
|
| Throws ||
|----------------------------------------------------------------------------|-------------------------|
| [IOException](https://developer.android.com/reference/java/io/IOException) | if an I/O error occurs. |
### close
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public void close ()
```
Closes this input stream and releases any system resources associated with the stream.
The`close`method of`CipherInputStream`calls the`close`method of its underlying input stream.
| Throws ||
|----------------------------------------------------------------------------|-------------------------|
| [IOException](https://developer.android.com/reference/java/io/IOException) | if an I/O error occurs. |
### markSupported
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public boolean markSupported ()
```
Tests if this input stream supports the`mark`and`reset`methods, which it does not.
| Returns ||
|-----------|-------------------------------------------------------------------------------|
| `boolean` | `false`, since this class does not support the`mark`and`reset`methods.
|
**See also:**
- [InputStream.mark(int)](https://developer.android.com/reference/java/io/InputStream#mark(int))
- [InputStream.reset()](https://developer.android.com/reference/java/io/InputStream#reset())
### read
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int read ()
```
Reads the next byte of data from this input stream. The value byte is returned as an`int`in the range`0`to`255`. If no byte is available because the end of the stream has been reached, the value`-1`is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
| Returns ||
|-------|--------------------------------------------------------------------------|
| `int` | the next byte of data, or`-1`if the end of the stream is reached.
|
| Throws ||
|----------------------------------------------------------------------------|-------------------------|
| [IOException](https://developer.android.com/reference/java/io/IOException) | if an I/O error occurs. |
### read
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int read (byte[] b,
int off,
int len)
```
Reads up to`len`bytes of data from this input stream into an array of bytes. This method blocks until some input is available. If the first argument is`null,`up to`len`bytes are read and discarded.
| Parameters ||
|-------|--------------------------------------------------------------|
| `b` | `byte`: the buffer into which the data is read.
|
| `off` | `int`: the start offset in the destination array`buf`
|
| `len` | `int`: the maximum number of bytes read.
|
| Returns ||
|-------|---------------------------------------------------------------------------------------------------------------------------------------|
| `int` | the total number of bytes read into the buffer, or`-1`if there is no more data because the end of the stream has been reached.
|
| Throws ||
|----------------------------------------------------------------------------|-------------------------|
| [IOException](https://developer.android.com/reference/java/io/IOException) | if an I/O error occurs. |
**See also:**
- [InputStream.read()](https://developer.android.com/reference/java/io/InputStream#read())
### read
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int read (byte[] b)
```
Reads up to`b.length`bytes of data from this input stream into an array of bytes.
The`read`method of`InputStream`calls the`read`method of three arguments with the arguments`b`,`0`, and`b.length`.
| Parameters ||
|-----|--------------------------------------------------------|
| `b` | `byte`: the buffer into which the data is read.
|
| Returns ||
|-------|---------------------------------------------------------------------------------------------------------------------------------------|
| `int` | the total number of bytes read into the buffer, or`-1`is there is no more data because the end of the stream has been reached.
|
| Throws ||
|----------------------------------------------------------------------------|-------------------------|
| [IOException](https://developer.android.com/reference/java/io/IOException) | if an I/O error occurs. |
**See also:**
- [InputStream.read(byte[], int, int)](https://developer.android.com/reference/java/io/InputStream#read(byte[],%20int,%20int))
### skip
Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public long skip (long n)
```
Skips`n`bytes of input from the bytes that can be read from this input stream without blocking.
Fewer bytes than requested might be skipped. The actual number of bytes skipped is equal to`n`or the result of a call to[available](https://developer.android.com/reference/javax/crypto/CipherInputStream#available()), whichever is smaller. If`n`is less than zero, no bytes are skipped.
The actual number of bytes skipped is returned.
| Parameters ||
|-----|---------------------------------------------------|
| `n` | `long`: the number of bytes to be skipped.
|
| Returns ||
|--------|--------------------------------------------|
| `long` | the actual number of bytes skipped.
|
| Throws ||
|----------------------------------------------------------------------------|-------------------------|
| [IOException](https://developer.android.com/reference/java/io/IOException) | if an I/O error occurs. |