public class CTR extends BaseMode implements java.lang.Cloneable
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:
algorithmParams, cipher, cipherBlockSize, iv, lock, modeBlockSize, name, stateALGORITHM_PARAMS, DECRYPTION, ENCRYPTION, IV, MODE_BLOCK_SIZE, STATECIPHER_BLOCK_SIZE, KEY_MATERIAL| Modifier and Type | Method and Description |
|---|---|
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.
|
blockSizes, currentBlockSize, defaultBlockSize, defaultKeySize, init, keySizes, name, reset, selfTest, updatepublic java.lang.Object clone()
IBlockCipherReturns a clone of this instance.
clone in interface IBlockCipherclone in class BaseModepublic void setup()
BaseModepublic void teardown()
BaseModepublic void encryptBlock(byte[] in,
int i,
byte[] out,
int o)
IBlockCipherEncrypts exactly one block of plaintext.
encryptBlock in interface IBlockCipherencryptBlock in class BaseModein - the plaintext.i - index of in from which to start considering
data.out - the ciphertext.o - index of out from which to store result.public void decryptBlock(byte[] in,
int i,
byte[] out,
int o)
IBlockCipherDecrypts exactly one block of ciphertext.
decryptBlock in interface IBlockCipherdecryptBlock in class BaseModein - the plaintext.i - index of in from which to start considering
data.out - the ciphertext.o - index of out from which to store result.Copyright © 2025. All rights reserved.