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java.lang.Object extended bygnu.crypto.mode.BaseMode extended bygnu.crypto.mode.CTR
The implementation of the Counter Mode.
The algorithm steps are formally described as follows:
CTR Encryption: O[j] = E(K)(T[j]); for j = 1, 2...n; C[j] = P[j] ^ O[j]; for j = 1, 2...n. CTR Decryption: O[j] = E(K)(T[j]); for j = 1, 2...n; P[j] = C[j] ^ O[j]; for j = 1, 2...n.
where P is the plaintext, C is the ciphertext,
E(K) is the underlying block cipher encryption function
parametrised with the session key K, and T is the
Counter.
This implementation, uses a standard incrementing function with a step of 1, and an initial value similar to that described in the NIST document.
References:
| Field Summary |
| Fields inherited from class gnu.crypto.mode.BaseMode |
cipher, cipherBlockSize, iv, lock, modeBlockSize, name, state |
| Fields inherited from interface gnu.crypto.mode.IMode |
DECRYPTION, ENCRYPTION, IV, MODE_BLOCK_SIZE, STATE |
| Fields inherited from interface gnu.crypto.cipher.IBlockCipher |
CIPHER_BLOCK_SIZE, KEY_MATERIAL |
| Constructor Summary | |
(package private) |
CTR(IBlockCipher underlyingCipher,
int cipherBlockSize)
Trivial package-private constructor for use by the Factory class. |
| Method Summary | |
java.lang.Object |
clone()
Returns a clone of this instance. |
void |
decryptBlock(byte[] in,
int i,
byte[] out,
int o)
Decrypts exactly one block of ciphertext. |
void |
encryptBlock(byte[] in,
int i,
byte[] out,
int o)
Encrypts exactly one block of plaintext. |
void |
setup()
The initialisation phase of the concrete mode implementation. |
void |
teardown()
The termination phase of the concrete mode implementation. |
| Methods inherited from class gnu.crypto.mode.BaseMode |
blockSizes, currentBlockSize, defaultBlockSize, defaultKeySize, init, keySizes, name, reset, selfTest, update |
| Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
CTR(IBlockCipher underlyingCipher, int cipherBlockSize)
Trivial package-private constructor for use by the Factory class.
underlyingCipher - the underlying cipher implementation.cipherBlockSize - the underlying cipher block size to use.| Method Detail |
public java.lang.Object clone()
IBlockCipherReturns a clone of this instance.
clone in interface IBlockCipherclone in class BaseModepublic void setup()
BaseMode
public void teardown()
BaseMode
public void encryptBlock(byte[] in, int i, byte[] out, int o)
IBlockCipherEncrypts exactly one block of plaintext.
encryptBlock in interface IBlockCipherencryptBlock in class BaseModepublic void decryptBlock(byte[] in, int i, byte[] out, int o)
IBlockCipherDecrypts exactly one block of ciphertext.
decryptBlock in interface IBlockCipherdecryptBlock in class BaseMode
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