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Class au.net.aba.crypto.provider.PBE

java.lang.Object
   |
   +----javax.crypto.CipherSpi
           |
           +----au.net.aba.crypto.provider.PBE

public abstract class PBE
extends CipherSpi
This class implements a basic password based encryption (PBE) algorithm. The particular implementation of PBE will specify the cipher and digest algorithms to use as well as the specific mechanism used to convert the supplied password into a secret key.


Variable Index

 o cipher
 o ident

Constructor Index

 o PBE(String)

Method Index

 o engineDoFinal(byte[], int, int)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
 o engineDoFinal(byte[], int, int, byte[], int)
Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
 o engineGetBlockSize()
Returns the block size (in bytes).
 o engineGetIV()
Returns the initialisation vector (IV) in a new buffer.
 o engineGetOutputSize(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 engineGetParameters()
Returns the parameters used with this cipher.
 o engineInit(int, Key, AlgorithmParameters, SecureRandom)
Initialises this cipher with a key, a set of algorithm parameters, and a source of randomness.
 o engineInit(int, Key, AlgorithmParameterSpec, SecureRandom)
Initialises this cipher with a key, a set of algorithm parameters, and a source of randomness.
 o engineInit(int, Key, SecureRandom)
Initialises this cipher with a key and a source of randomness.
 o engineSetMode(String)
Sets the mode of this cipher.
 o engineSetPadding(String)
Sets the padding mechanism of this cipher.
 o engineUpdate(byte[], int, int)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.
 o engineUpdate(byte[], int, int, byte[], int)
Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialised), processing another data part.
 o initCipher(int, byte[], int, char[])
This method is provided by the specific implementation to create the digest from the password and the algorithm parameters.

Variables

 o ident
 public static final String ident
 o cipher
 protected Cipher cipher

Constructors

 o PBE
 protected PBE(String cipherName)

Methods

 o engineSetMode
 protected void engineSetMode(String mode) throws NoSuchAlgorithmException
Sets the mode of this cipher. Generally PBE ciphers only operate in a single mode and so this method will throw an exception.

Parameters:
mode - the cipher mode
Throws: NoSuchAlgorithmException
if the requested cipher mode does not exist
Overrides:
engineSetMode in class CipherSpi
 o engineSetPadding
 protected void engineSetPadding(String padding) throws NoSuchPaddingException
Sets the padding mechanism of this cipher. Generally PBE ciphers only operate in a single mode and so this method will throw an exception.

Parameters:
padding - the padding mechanism
Throws: NoSuchPaddingException
if the requested padding mechanism does not exist.
Overrides:
engineSetPadding in class CipherSpi
 o engineGetBlockSize
 protected int engineGetBlockSize()
Returns the block size (in bytes). This method will return the block size of the underlying Cipher.

Returns:
the block size (in bytes), or 0 if the underlying algorithm is not a block cipher
Overrides:
engineGetBlockSize in class CipherSpi
 o engineGetOutputSize
 protected int engineGetOutputSize(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 method will return a result based on the underlying cipher.

Parameters:
inputLen - the input length (in bytes)
Returns:
the required output buffer size (in bytes)
Overrides:
engineGetOutputSize in class CipherSpi
 o engineGetIV
 protected byte[] engineGetIV()
Returns the initialisation vector (IV) in a new buffer.

This is useful in the context of password-based encryption or decryption, where the IV is derived from a user-provided passphrase.

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.
Overrides:
engineGetIV in class CipherSpi
 o engineGetParameters
 protected AlgorithmParameters engineGetParameters()
Returns the parameters used with this cipher.

Currently, the PBE ciphers do not support this method.

Returns:
the parameters used with this cipher, or null if this cipher does not use any parameters.
Overrides:
engineGetParameters in class CipherSpi
 o engineInit
 protected void engineInit(int opmode,
                           Key key,
                           SecureRandom random) throws InvalidKeyException
Initialises this cipher with a key and a source of randomness.

This method of initialisation is not supported for PBE ciphers as they require parameterisation that cannot be generated by the cipher.

Overrides:
engineInit in class CipherSpi
 o engineInit
 protected void engineInit(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 key must be a PBEKey and the algorithm parameter spec must be a PBEParameterSpec.

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

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 not a PBEKey
Throws: InvalidAlgorithmParameterException
if the given algorithm parameter instance is not a PBEParameterSpec.
Overrides:
engineInit in class CipherSpi
 o engineInit
 protected void engineInit(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.

Attempts to convert the supplied algorithm parameters into a PBEParameterSpec and then initialise the cipher as above.

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 not a PBEKey
Throws: InvalidAlgorithmParameterException
if the given algorithm parameters cannot be converted into a PBEParameterSpec
Overrides:
engineInit in class CipherSpi
 o engineUpdate
 protected byte[] engineUpdate(byte input[],
                               int inputOff,
                               int inputLen)
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 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.
Overrides:
engineUpdate in class CipherSpi
 o engineUpdate
 protected int engineUpdate(byte input[],
                            int inputOff,
                            int inputLen,
                            byte output[],
                            int outputOff) throws 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: ShortBufferException
if the given output buffer is too small to hold the result
Overrides:
engineUpdate in class CipherSpi
 o engineDoFinal
 protected byte[] engineDoFinal(byte input[],
                                int inputOffset,
                                int inputLen) throws 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.

The cipher is reset to its initial state (uninitialised) after this call.

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: 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.
Overrides:
engineDoFinal in class CipherSpi
 o engineDoFinal
 protected int engineDoFinal(byte input[],
                             int inputOff,
                             int inputLen,
                             byte output[],
                             int outputOff) throws 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.

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:
s the number of bytes stored in output
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
Overrides:
engineDoFinal in class CipherSpi
 o initCipher
 protected abstract void initCipher(int opmode,
                                    byte salt[],
                                    int iteration,
                                    char password[])
This method is provided by the specific implementation to create the digest from the password and the algorithm parameters. This digest is then used to create the SecretKey and the IV for the cipher.


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