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Class javax.crypto.Cipher

java.lang.Object
   |
   +----javax.crypto.Cipher

public class Cipher
extends Object
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:

(in the latter case provider-specific defaults values for mode and padding scheme are used). For example, the following is a valid transformation:
 Cipher c = Cipher.getInstance("DES/CBC/PKCS5Padding");
 

When requesting a block cipher in stream cipher mode (e.g., DES in CFB or OFB mode), the user 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.)

See Also:
KeyGenerator, SecretKey

Variable Index

 o DECRYPT_MODE
 o ENCRYPT_MODE
 o ident

Constructor Index

 o Cipher(CipherSpi, Provider, String)
Creates a Cipher object.

Method Index

 o doFinal()
Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialised.
 o doFinal(byte[])
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
 o doFinal(byte[], int)
Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialised.
 o doFinal(byte[], int, int)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
 o doFinal(byte[], int, int, byte[])
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
 o doFinal(byte[], int, int, byte[], int)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
 o getAlgorithm()
Returns the algorithm name of this Cipher object.
 o getBlockSize()
Returns the block size (in bytes).
 o getInstance(String)
Generates a Cipher object that implements the specified transformation.
 o getInstance(String, String)
Creates a Cipher object that implements the specified transformation, as supplied by the specified provider.
 o getIV()
Returns the initialisation vector (IV) in a new buffer.
 o getOutputSize(int)
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).
 o getParameters()
Returns the parameters used with this cipher.
 o getProvider()
Returns the provider of this Cipher object.
 o init(int, Key)
Initialises this cipher with a key.
 o init(int, Key, AlgorithmParameters)
Initialises this cipher with a key and a set of algorithm parameters.
 o init(int, Key, AlgorithmParameters, SecureRandom)
Initialises this cipher with a key, a set of algorithm parameters, and a source of randomness.
 o init(int, Key, AlgorithmParameterSpec)
Initialises this cipher with a key and a set of algorithm parameters.
 o init(int, Key, AlgorithmParameterSpec, SecureRandom)
Initialises this cipher with a key, a set of algorithm parameters, and a source of randomness.
 o init(int, Key, SecureRandom)
Initialises this cipher with a key and a source of randomness.
 o update(byte[])
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.
 o update(byte[], int, int)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.
 o update(byte[], int, int, byte[])
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.
 o update(byte[], int, int, byte[], int)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.

Variables

 o ident
 public static final String ident
 o ENCRYPT_MODE
 public static final int ENCRYPT_MODE
 o DECRYPT_MODE
 public static final int DECRYPT_MODE

Constructors

 o Cipher
 protected Cipher(CipherSpi cipherSpi,
                  Provider provider,
                  String transformation)
Creates a Cipher object.

Parameters:
cipherSpi - the delegate
provider - the provider
transformation - the transformation

Methods

 o getInstance
 public static final Cipher getInstance(String transformation) throws NoSuchAlgorithmException, NoSuchPaddingException
Generates a Cipher object that implements the specified transformation.

If the default provider package provides an implementation of the requested transformation, an instance of Cipher containing that implementation is returned. If the transformation is not available in the default provider package, other provider packages are searched.

Parameters:
transformation - the name of the transformation, e.g., DES/CBC/PKCS5Padding. See Appendix A in the Java Cryptography Extension API Specification & Reference for information about standard transformation names.
Returns:
a cipher that implements the requested transformation
Throws: NoSuchAlgorithmException
if the requested algorithm is not available in the default provider package or any of the other provider packages that were searched.
Throws: NoSuchPaddingException
if transformation contains a scheme that is not available.
 o getInstance
 public static final Cipher getInstance(String transformation,
                                        String provider) throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException
Creates a Cipher object that implements the specified transformation, as supplied by the specified provider.

Parameters:
transformation - the name of the transformation, e.g., DES/CBC/PKCS5Padding. See Appendix A in the Java Cryptography Extension API Specification & Reference for information about standard transformation names.
provider - the name of the cipher provider
Returns:
a cipher that implements the requested transformation
Throws: NoSuchAlgorithmException
if the requested algorithm is not available
Throws: NoSuchProviderException
if the requested provider is not available
Throws: NoSuchPaddingException
if the requested padding mechanism is not available
See Also:
Provider
 o getProvider
 public final Provider getProvider()
Returns the provider of this Cipher object.

Returns:
Returns the provider of this Cipher object.
 o getAlgorithm
 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:
the algorithm name of this Cipher object.
 o getBlockSize
 public final int getBlockSize()
Returns the block size (in bytes).

Returns:
the block size (in bytes), or 0 if the underlying algorithm is not a block cipher
 o getOutputSize
 public final int getOutputSize(int inputLen) throws IllegalStateException
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, and padding.

The actual output length of the next update or doFinal call may be smaller than the length returned by this method.

Parameters:
inputLen - the input length (in bytes)
Returns:
the required output buffer size (in bytes)
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not yet been initialised)
 o getIV
 public final byte[] getIV()
Returns the initialisation 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:
the initialisation 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.
 o getParameters
 public final AlgorithmParameters getParameters()
Returns the parameters used with this cipher.

The returned parameters may be the same that were used to initialise 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 initialised with any.

Returns:
the parameters used with this cipher, or null if this cipher does not use any parameters.
 o init
 public final void init(int opmode,
                        Key key) throws InvalidKeyException
Initialises this cipher with a key.

The cipher is initialised for encryption or decryption, depending on the value of opmode.

If this cipher requires any algorithm parameters that cannot be derived from the give key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider0specific default or random values) if it is being initialised for encryption, and raise and InvalidKeyException if it is being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).

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 initialised, it loses all previously acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.

Parameters:
opmode - the operation mode of this cipher (this is either ENCRYPT_MODE or DECRYPT_MODE)
key - the key
Throws: InvalidKeyException
if the given key is inappropriate for initialising this cipher, or if this cipher is being initialised for decryption and requires algorithm parameters that cannot be determined from the given key.
 o init
 public final void init(int opmode,
                        Key key,
                        SecureRandom random) throws InvalidKeyException
Initialises this cipher with a key and a source of randomness.

The cipher is initialised for encryption or decryption, depending on the value of opmode.

If this cipher requires any algorithm parameters that cannot be derived from the give key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider0specific default or random values) if it is being initialised for encryption, and raise and InvalidKeyException if it is being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).

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 initialised, it loses all previously acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.

Parameters:
opmode - the operation mode of this cipher (this is either ENCRYPT_MODE or DECRYPT_MODE)
key - the encryption key
random - the source of randomness
Throws: InvalidKeyException
if the given key is inappropriate for initialising this cipher, or if the cipher is being initialised for decryption and requires algorithm parameters that cannot be determined from the given key.
 o init
 public final void init(int opmode,
                        Key key,
                        AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException
Initialises this cipher with a key and a set of algorithm parameters.

The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).

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 initialised, it loses all previously acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.

Parameters:
opmode - the operation mode of this cipher (this is either ENCRYPT_MODE or DECRYPT_MODE)
key - the encryption key
params - the algorithm parameters
Throws: InvalidKeyException
if the given key is inappropriate for initialising this cipher.
Throws: InvalidAlgorithmParameterException
if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialised for decryption and requires algorithm parameters and params is null.
 o init
 public final void init(int opmode,
                        Key key,
                        AlgorithmParameterSpec params,
                        SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException
Initialises this cipher with a key, a set of algorithm parameters, and a source of randomness.

The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).

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 initialised, it loses all previously-acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher, and initialising it.

Parameters:
opmode - the operation mode of this cipher (this is either ENCRYPT_MODE or DECRYPT_MODE)
key - the encryption key
params - the algorithm parameters
random - the source of randomness
Throws: InvalidKeyException
if the given key is inappropriate for initialising this cipher
Throws: InvalidAlgorithmParameterException
if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialised for decryption and requires algorithm parameters and params is null.
 o init
 public final void init(int opmode,
                        Key key,
                        AlgorithmParameters params) throws InvalidKeyException, InvalidAlgorithmParameterException
Initialises this cipher with a key and a set of algorithm parameters.

The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).

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 initialised, it loses all previously-acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.

Parameters:
opmode - the operation mode of this cipher (this is either ENCRYPT_MODE or DECRYPT_MODE)
key - the encryption key
params - the algorithm parameters
Throws: InvalidKeyException
- if the given key is inappropriate for initialising this cipher
Throws: InvalidAlgorithmParameterException
if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialised for decryption and requires algorithm parameters and params is null.
 o init
 public final void init(int opmode,
                        Key key,
                        AlgorithmParameters params,
                        SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException
Initialises this cipher with a key, a set of algorithm parameters, and a source of randomness.

The cipher is initialised for encryption or decryption, 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 by itself (using provider-specific default or random values) if it is being initialised for encryption, and raise an InvalidAlgorithmParameterException if it being initialised for decryption. The generated parameters can be retrieved using getParameters or getIV (if the parameter is an IV).

If this cipher (including its underlying feedback or padding scheme) requires any random bytes, it will get them from random.

Note that when a Cipher object is initialised, it loses all previously-acquired state. In other words, initialising a Cipher is equivalent to creating a new instance of that Cipher and initialising it.

Parameters:
opmode - the operation mode of this cipher (this is either ENCRYPT_MODE or DECRYPT_MODE)
key - the encryption key
params - the algorithm parameters
random - the source of randomness
Throws: InvalidKeyException
if the given key is inappropriate for initialising this cipher
Throws: InvalidAlgorithmParameterException
if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialised for decryption and requires algorithm parameters and params is null.
 o update
 public final byte[] update(byte input[]) throws IllegalStateException
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.

The bytes in the input buffer are processed, and the result is stored in a new buffer.

Parameters:
input - the input buffer
Returns:
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: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
 o update
 public final byte[] update(byte input[],
                            int inputOffset,
                            int inputLen) throws IllegalStateException
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), 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.

Parameters:
input - the input buffer
inputOffset - the offset in input where the input starts
inputLen - the input length
Returns:
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: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
 o update
 public final int update(byte input[],
                         int inputOffset,
                         int inputLen,
                         byte output[]) throws IllegalStateException, ShortBufferException
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), 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 getOutputSize to determine how big the output buffer should be.

Parameters:
input - - the input buffer
inputOffset - - the offset in input where the input starts
inputLen - - the input length
output - - the buffer for the result
Returns:
the number of bytes stored in output
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: ShortBufferException
if the given output buffer is too small to hold the result.
 o update
 public final int update(byte input[],
                         int inputOffset,
                         int inputLen,
                         byte output[],
                         int outputOffset) throws IllegalStateException, ShortBufferException
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.

The first inputLen bytes in the input buffer, starting at inputOffset, are processed, and the result is stored in the output buffer, starting at outputOffset.

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 getOutputSize to determine how big the output buffer should be.

Parameters:
input - the input buffer
inputOffset - the offset in input where the input starts
inputLen - the input length
output - the buffer for the result
outputOffset - the offset in output where the result is stored
Returns:
the number of bytes stored in output
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: ShortBufferException
if the given output buffer is too small to hold the result
 o doFinal
 public final byte[] doFinal() throws IllegalStateException, IllegalBlockSizeException, BadPaddingException
Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialised.

Input data that may have been buffered during a previous update operation is processed, with padding (if requested) being applied. The result is stored in a new buffer.

A call to this method resets this cipher object to the state it was in when previously initialised 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.

Returns:
s the new buffer with the result
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: 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
Throws: 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.
 o doFinal
 public final int doFinal(byte output[],
                          int outputOffset) throws IllegalStateException, IllegalBlockSizeException, ShortBufferException, BadPaddingException
Finishes a multiple-part encryption or decryption operation, depending on how this cipher was initialised.

Input data that may have been buffered during a previous update operation is processed, with padding (if requested) being applied. The result is stored in the output buffer, starting at outputOffset.

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 getOutputSize to determine how big the output buffer should be.

A call to this method resets this cipher object to the state it was in when previously initialised 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.

Parameters:
output - the buffer for the result
outputOffset - the offset in output where the result is stored
Returns:
the number of bytes stored in output
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: 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
Throws: ShortBufferException
if the given output buffer is too small to hold the result
Throws: 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
 o doFinal
 public final byte[] doFinal(byte input[]) throws IllegalStateException, IllegalBlockSizeException, BadPaddingException
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 initialised.

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. The result is stored in a new buffer.

A call to this method resets this cipher object to the state it was in when previously initialised 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.

Parameters:
input - - the input buffer
Returns:
s the new buffer with the result
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: 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
Throws: 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
 o doFinal
 public final byte[] doFinal(byte input[],
                             int inputOffset,
                             int inputLen) throws IllegalStateException, IllegalBlockSizeException, BadPaddingException
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 initialised.

The first inputLen bytes in the input buffer, starting at inputOffset, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. The result is stored in a new buffer.

A call to this method resets this cipher object to the state it was in when previously initialised 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.

Parameters:
input - - the input buffer
inputOffset - - the offset in input where the input starts
inputLen - - the input length
Returns:
the new buffer with the result
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: 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
Throws: 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
 o doFinal
 public final int doFinal(byte input[],
                          int inputOffset,
                          int inputLen,
                          byte output[]) throws IllegalStateException, ShortBufferException, IllegalBlockSizeException, BadPaddingException
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 initialised.

The first inputLen bytes in the input buffer, starting at inputOffset, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. 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 getOutputSize to determine how big the output buffer should be.

A call to this method resets this cipher object to the state it was in when previously initialised 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.

Parameters:
input - - the input buffer
inputOffset - - the offset in input where the input starts
inputLen - - the input length
output - - the buffer for the result
Returns:
the number of bytes stored in output
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: 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
Throws: ShortBufferException
if the given output buffer is too small to hold the result
Throws: 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
 o doFinal
 public final int doFinal(byte input[],
                          int inputOffset,
                          int inputLen,
                          byte output[],
                          int outputOffset) throws IllegalStateException, ShortBufferException, IllegalBlockSizeException, BadPaddingException
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 initialised.

The first inputLen bytes in the input buffer, starting at inputOffset, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. The result is stored in the output buffer, starting at outputOffset.

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 getOutputSize to determine how big the output buffer should be.

A call to this method resets this cipher object to the state it was in when previously initialised 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.

Parameters:
input - the input buffer
inputOffset - the offset in input where the input starts
inputLen - the input length
output - the buffer for the result
outputOffset - the offset in output where the result is stored
Returns:
the number of bytes stored in output
Throws: IllegalStateException
if this cipher is in a wrong state (e.g., has not been initialised)
Throws: 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
Throws: ShortBufferException
if the given output buffer is too small to hold the result
Throws: 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

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