org.mozilla.jss.crypto

Class Cipher

java.lang.Object

org.mozilla.jss.crypto.Cipher

public abstract class Cipher
extends java.lang.Object

A context for performing symmetric encryption and decryption. First, the context must be initialized. Then, it can be updated with input through zero or more calls to update. Finally, doFinal is called to finalize the operation. Note that it is not necessary to call update if all of the data is available at once. In this case, all of the input can be processed with one call to doFinal.

Constructor Summary

Constructors

Constructor and Description
Cipher()

Method Summary

Modifier and Type	Method and Description
abstract byte[]	doFinal() Completes an cipher operation.
abstract byte[]	doFinal(byte[] bytes) Completes an cipher operation.
abstract byte[]	doFinal(byte[] bytes, int offset, int length) Completes an cipher operation.
abstract void	initDecrypt(SymmetricKey key) Initializes a decryption context with a symmetric key.
abstract void	initDecrypt(SymmetricKey key, java.security.spec.AlgorithmParameterSpec parameters) Initializes a decryption context with a symmetric key and algorithm parameters.
abstract void	initEncrypt(SymmetricKey key) Initializes a encryption context with a symmetric key.
abstract void	initEncrypt(SymmetricKey key, java.security.spec.AlgorithmParameterSpec parameters) Initializes an encryption context with a symmetric key and algorithm parameters.
static byte[]	pad(byte[] toBePadded, int blockSize) Pads a byte array so that its length is a multiple of the given blocksize.
static byte[]	unPad(byte[] padded) Un-pads a byte array that is padded with PKCS padding.
static byte[]	unPad(byte[] padded, int blockSize) Un-pads a byte array that is padded with PKCS padding.
abstract byte[]	update(byte[] bytes) Updates the encryption context with additional input.
abstract byte[]	update(byte[] bytes, int offset, int length) Updates the encryption context with additional plaintext.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Cipher

public Cipher()

Method Detail

initEncrypt

public abstract void initEncrypt(SymmetricKey key)
                          throws java.security.InvalidKeyException,
                                 java.security.InvalidAlgorithmParameterException,
                                 TokenException

Initializes a encryption context with a symmetric key.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

TokenException

initDecrypt

public abstract void initDecrypt(SymmetricKey key)
                          throws java.security.InvalidKeyException,
                                 java.security.InvalidAlgorithmParameterException,
                                 TokenException

Initializes a decryption context with a symmetric key.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

TokenException

initEncrypt

public abstract void initEncrypt(SymmetricKey key,
                                 java.security.spec.AlgorithmParameterSpec parameters)
                          throws java.security.InvalidKeyException,
                                 java.security.InvalidAlgorithmParameterException,
                                 TokenException

Initializes an encryption context with a symmetric key and algorithm parameters.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

TokenException

initDecrypt

public abstract void initDecrypt(SymmetricKey key,
                                 java.security.spec.AlgorithmParameterSpec parameters)
                          throws java.security.InvalidKeyException,
                                 java.security.InvalidAlgorithmParameterException,
                                 TokenException

Initializes a decryption context with a symmetric key and algorithm parameters.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

TokenException

update

public abstract byte[] update(byte[] bytes)
                       throws java.lang.IllegalStateException,
                              TokenException

Updates the encryption context with additional input.

Parameters:

bytes - Bytes of plaintext (if encrypting) or ciphertext (if decrypting).

Returns:

Bytes of ciphertext (if encrypting) or plaintext (if decrypting).

Throws:

java.lang.IllegalStateException

TokenException

update

public abstract byte[] update(byte[] bytes,
                              int offset,
                              int length)
                       throws java.lang.IllegalStateException,
                              TokenException

Updates the encryption context with additional plaintext.

Parameters:

bytes - Bytes of plaintext (if encrypting) or ciphertext (if decrypting).

offset - The index in bytes at which to begin reading.

length - The number of bytes from bytes to read.

Returns:

Bytes of ciphertext (if encrypting) or plaintext (if decrypting).

Throws:

java.lang.IllegalStateException

TokenException

doFinal

public abstract byte[] doFinal(byte[] bytes)
                        throws java.lang.IllegalStateException,
                               IllegalBlockSizeException,
                               javax.crypto.BadPaddingException,
                               TokenException

Completes an cipher operation. This can be called directly after the context is initialized, or update may be called any number of times before calling final.

Parameters:

bytes - Bytes of plaintext (if encrypting) or ciphertext (if decrypting).

Returns:

The last of the output.

Throws:

java.lang.IllegalStateException

IllegalBlockSizeException

javax.crypto.BadPaddingException

TokenException

doFinal

public abstract byte[] doFinal(byte[] bytes,
                               int offset,
                               int length)
                        throws java.lang.IllegalStateException,
                               IllegalBlockSizeException,
                               javax.crypto.BadPaddingException,
                               TokenException

Completes an cipher operation.

Parameters:

bytes - Bytes of plaintext (if encrypting) or ciphertext (if decrypting).

offset - The index in bytes at which to begin reading.

length - The number of bytes from bytes to read.

Returns:

The last of the output.

Throws:

java.lang.IllegalStateException

IllegalBlockSizeException

javax.crypto.BadPaddingException

TokenException

doFinal

public abstract byte[] doFinal()
                        throws java.lang.IllegalStateException,
                               IllegalBlockSizeException,
                               javax.crypto.BadPaddingException,
                               TokenException

Completes an cipher operation.

Returns:

The last of the output.

Throws:

java.lang.IllegalStateException

IllegalBlockSizeException

javax.crypto.BadPaddingException

TokenException

pad

public static byte[] pad(byte[] toBePadded,
                         int blockSize)

Pads a byte array so that its length is a multiple of the given blocksize. The method of padding is the one defined in the RSA PKCS standards. If M is the length of the data and B is the block size, the padding string consists of B - (M mod B) octets, each having the value B - (M mod B).

Parameters:

toBePadded - The byte array to pad.

blockSize - The block size of the encryption algorithm. Must be greater than zero.

See Also:

unPad(byte[], int)

unPad

public static byte[] unPad(byte[] padded,
                           int blockSize)
                    throws javax.crypto.BadPaddingException

Un-pads a byte array that is padded with PKCS padding.

Parameters:

blockSize - The block size of the encryption algorithm. This is only used for error checking: if the pad size is not between 1 and blockSize, a BadPaddingException is thrown.

Throws:

javax.crypto.BadPaddingException

See Also:

pad(byte[], int)

unPad

public static byte[] unPad(byte[] padded)
                    throws javax.crypto.BadPaddingException

Un-pads a byte array that is padded with PKCS padding. Since this version does not take block size as a parameter, it cannot error check.

Throws:

javax.crypto.BadPaddingException

See Also:

pad(byte[], int)