ECB, CFB, OFB,
* CBC, PCBC) and padding schemes
* (PKCS5Padding, NoPadding,
* ISO10126Padding).
*
* @author Gigi Ankeny
*
*
* @see DESCipher
*/
public final class DESedeCipher extends CipherSpi {
/*
* internal CipherCore object which does the real work.
*/
private CipherCore core = null;
/**
* Creates an instance of DESede cipher with default ECB mode and
* PKCS5Padding.
*/
public DESedeCipher() {
core = new CipherCore(new DESedeCrypt(), DESConstants.DES_BLOCK_SIZE);
}
/**
* Sets the mode of this cipher.
*
* @param mode the cipher mode
*
* @exception NoSuchAlgorithmException if the requested cipher mode does
* not exist
*/
protected void engineSetMode(String mode)
throws NoSuchAlgorithmException {
core.setMode(mode);
}
/**
* Sets the padding mechanism of this cipher.
*
* @param padding the padding mechanism
*
* @exception NoSuchPaddingException if the requested padding mechanism
* does not exist
*/
protected void engineSetPadding(String paddingScheme)
throws NoSuchPaddingException {
core.setPadding(paddingScheme);
}
/**
* Returns the block size (in bytes).
*
* @return the block size (in bytes), or 0 if the underlying algorithm is
* not a block cipher
*/
protected int engineGetBlockSize() {
return DESConstants.DES_BLOCK_SIZE;
}
/**
* 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.
*
* @param inputLen the input length (in bytes)
*
* @return the required output buffer size (in bytes)
*/
protected int engineGetOutputSize(int inputLen) {
return core.getOutputSize(inputLen);
}
/**
* Returns the initialization vector (IV) in a new buffer.
*
*
This is useful in the case where a random IV has been created * (see init), * or in the context of password-based encryption or * decryption, where the IV is derived from a user-provided password. * * @return the initialization 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. */ protected byte[] engineGetIV() { return core.getIV(); } /** * Initializes this cipher with a key and a source of randomness. * *
The cipher is initialized for one of the following four operations:
* encryption, decryption, key wrapping or key unwrapping, depending on
* the value of opmode.
*
*
If this cipher requires an initialization vector (IV), it will get
* it from random.
* This behaviour should only be used in encryption or key wrapping
* mode, however.
* When initializing a cipher that requires an IV for decryption or
* key unwrapping, the IV
* (same IV that was used for encryption or key wrapping) must be provided
* explicitly as a
* parameter, in order to get the correct result.
*
*
This method also cleans existing buffer and other related state
* information.
*
* @param opmode the operation mode of this cipher (this is one of
* the following:
* ENCRYPT_MODE, DECRYPT_MODE,
* WRAP_MODE or UNWRAP_MODE)
* @param key the secret key
* @param random the source of randomness
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this cipher
*/
protected void engineInit(int opmode, Key key, SecureRandom random)
throws InvalidKeyException {
core.init(opmode, key, random);
}
/**
* Initializes this cipher with a key, a set of
* algorithm parameters, and a source of randomness.
*
*
The cipher is initialized for one of the following four operations:
* encryption, decryption, key wrapping or key unwrapping, depending on
* the value of opmode.
*
*
If this cipher (including its underlying feedback or padding scheme)
* requires any random bytes, it will get them from random.
*
* @param opmode the operation mode of this cipher (this is one of
* the following:
* ENCRYPT_MODE, DECRYPT_MODE,
* WRAP_MODE or UNWRAP_MODE)
* @param key the encryption key
* @param params the algorithm parameters
* @param random the source of randomness
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this cipher
* @exception InvalidAlgorithmParameterException if the given algorithm
* parameters are inappropriate for this cipher
*/
protected void engineInit(int opmode, Key key,
AlgorithmParameterSpec params,
SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException {
core.init(opmode, key, params, random);
}
protected void engineInit(int opmode, Key key,
AlgorithmParameters params,
SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException {
core.init(opmode, key, params, random);
}
/**
* Continues a multiple-part encryption or decryption operation
* (depending on how this cipher was initialized), 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.
*
* @param input the input buffer
* @param inputOffset the offset in input where the input
* starts
* @param inputLen the input length
*
* @return the new buffer with the result
*
* @exception IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
*/
protected byte[] engineUpdate(byte[] input, int inputOffset,
int inputLen) {
return core.update(input, inputOffset, inputLen);
}
/**
* Continues a multiple-part encryption or decryption operation
* (depending on how this cipher was initialized), 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.
*
* @param input the input buffer
* @param inputOffset the offset in input where the input
* starts
* @param inputLen the input length
* @param output the buffer for the result
* @param outputOffset the offset in output where the result
* is stored
*
* @return the number of bytes stored in output
*
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
*/
protected int engineUpdate(byte[] input, int inputOffset, int inputLen,
byte[] output, int outputOffset)
throws ShortBufferException {
return core.update(input, inputOffset, inputLen, output,
outputOffset);
}
/**
* 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
* initialized.
*
*
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 (uninitialized) after this
* call.
*
* @param input the input buffer
* @param inputOffset the offset in input where the input
* starts
* @param inputLen the input length
*
* @return the new buffer with the result
*
* @exception 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
* @exception 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
*/
protected byte[] engineDoFinal(byte[] input, int inputOffset,
int inputLen)
throws IllegalBlockSizeException, BadPaddingException {
return core.doFinal(input, inputOffset, inputLen);
}
/**
* 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
* initialized.
*
*
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.
*
*
The cipher is reset to its initial state (uninitialized) after this
* call.
*
* @param input the input buffer
* @param inputOffset the offset in input where the input
* starts
* @param inputLen the input length
* @param output the buffer for the result
* @param outputOffset the offset in output where the result
* is stored
*
* @return the number of bytes stored in output
*
* @exception 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
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
* @exception 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
*/
protected int engineDoFinal(byte[] input, int inputOffset, int inputLen,
byte[] output, int outputOffset)
throws IllegalBlockSizeException, ShortBufferException,
BadPaddingException {
return core.doFinal(input, inputOffset, inputLen, output,
outputOffset);
}
/**
* Returns the parameters used with this cipher.
*
*
The returned parameters may be the same that were used to initialize
* this cipher, or may contain the default set of parameters or a set of
* randomly generated parameters used by the underlying cipher
* implementation (provided that the underlying cipher implementation
* uses a default set of parameters or creates new parameters if it needs
* parameters but was not initialized with any).
*
* @return the parameters used with this cipher, or null if this cipher
* does not use any parameters.
*/
protected AlgorithmParameters engineGetParameters() {
return core.getParameters("DESede");
}
/**
* Returns the key size of the given key object.
*
* @param key the key object.
*
* @return the "effective" key size of the given key object.
*
* @exception InvalidKeyException if key is invalid.
*/
protected int engineGetKeySize(Key key) throws InvalidKeyException {
byte[] encoded = key.getEncoded();
if (encoded.length != 24) {
throw new InvalidKeyException("Invalid key length: " +
encoded.length + " bytes");
}
// Return the effective key length
return 112;
}
/**
* Wrap a key.
*
* @param key the key to be wrapped.
*
* @return the wrapped key.
*
* @exception IllegalBlockSizeException if this cipher is a block
* cipher, no padding has been requested, and the length of the
* encoding of the key to be wrapped is not a
* multiple of the block size.
*
* @exception InvalidKeyException if it is impossible or unsafe to
* wrap the key with this cipher (e.g., a hardware protected key is
* being passed to a software only cipher).
*/
protected byte[] engineWrap(Key key)
throws IllegalBlockSizeException, InvalidKeyException {
return core.wrap(key);
}
/**
* Unwrap a previously wrapped key.
*
* @param wrappedKey the key to be unwrapped.
*
* @param wrappedKeyAlgorithm the algorithm the wrapped key is for.
*
* @param wrappedKeyType the type of the wrapped key.
* This is one of Cipher.SECRET_KEY,
* Cipher.PRIVATE_KEY, or Cipher.PUBLIC_KEY.
*
* @return the unwrapped key.
*
* @exception NoSuchAlgorithmException if no installed providers
* can create keys of type wrappedKeyType for the
* wrappedKeyAlgorithm.
*
* @exception InvalidKeyException if wrappedKey does not
* represent a wrapped key of type wrappedKeyType for
* the wrappedKeyAlgorithm.
*/
protected Key engineUnwrap(byte[] wrappedKey,
String wrappedKeyAlgorithm,
int wrappedKeyType)
throws InvalidKeyException, NoSuchAlgorithmException {
return core.unwrap(wrappedKey, wrappedKeyAlgorithm,
wrappedKeyType);
}
}