org.bouncycastle.crypto.modes
Class EAXBlockCipher
java.lang.Object
org.bouncycastle.crypto.modes.EAXBlockCipher
- AEADBlockCipher
public class EAXBlockCipher
extends java.lang.Object
A Two-Pass Authenticated-Encryption Scheme Optimized for Simplicity and
Efficiency - by M. Bellare, P. Rogaway, D. Wagner.
http://www.cs.ucdavis.edu/~rogaway/papers/eax.pdf
EAX is an AEAD scheme based on CTR and OMAC1/CMAC, that uses a single block
cipher to encrypt and authenticate data. It's on-line (the length of a
message isn't needed to begin processing it), has good performances, it's
simple and provably secure (provided the underlying block cipher is secure).
Of course, this implementations is NOT thread-safe.
int | doFinal(byte[] out, int outOff) - Finish the operation either appending or verifying the MAC at the end of the data.
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String | getAlgorithmName() - Return the name of the algorithm.
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int | getBlockSize()
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byte[] | getMac() - Return the value of the MAC associated with the last stream processed.
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int | getOutputSize(int len) - return the size of the output buffer required for a processBytes plus a
doFinal with an input of len bytes.
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BlockCipher | getUnderlyingCipher() - return the cipher this object wraps.
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int | getUpdateOutputSize(int len) - return the size of the output buffer required for a processBytes
an input of len bytes.
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void | init(boolean forEncryption, CipherParameters params) - initialise the underlying cipher.
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int | processByte(byte in, byte[] out, int outOff) - encrypt/decrypt a single byte.
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int | processBytes(byte[] in, int inOff, int len, byte[] out, int outOff) - process a block of bytes from in putting the result into out.
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void | reset() - Reset the cipher.
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EAXBlockCipher
public EAXBlockCipher(BlockCipher cipher)
Constructor that accepts an instance of a block cipher engine.
cipher
- the engine to use
doFinal
public int doFinal(byte[] out,
int outOff)
throws IllegalStateException,
InvalidCipherTextException
Finish the operation either appending or verifying the MAC at the end of the data.
- doFinal in interface AEADBlockCipher
out
- space for any resulting output data.outOff
- offset into out to start copying the data at.
- number of bytes written into out.
getBlockSize
public int getBlockSize()
getMac
public byte[] getMac()
Return the value of the MAC associated with the last stream processed.
- getMac in interface AEADBlockCipher
getOutputSize
public int getOutputSize(int len)
return the size of the output buffer required for a processBytes plus a
doFinal with an input of len bytes.
- getOutputSize in interface AEADBlockCipher
len
- the length of the input.
- the space required to accommodate a call to processBytes and doFinal
with len bytes of input.
getUpdateOutputSize
public int getUpdateOutputSize(int len)
return the size of the output buffer required for a processBytes
an input of len bytes.
- getUpdateOutputSize in interface AEADBlockCipher
len
- the length of the input.
- the space required to accommodate a call to processBytes
with len bytes of input.
init
public void init(boolean forEncryption,
CipherParameters params)
throws IllegalArgumentException
initialise the underlying cipher. Parameter can either be an AEADParameters or a ParametersWithIV object.
- init in interface AEADBlockCipher
forEncryption
- true if we are setting up for encryption, false otherwise.params
- the necessary parameters for the underlying cipher to be initialised.
processByte
public int processByte(byte in,
byte[] out,
int outOff)
throws DataLengthException
encrypt/decrypt a single byte.
- processByte in interface AEADBlockCipher
in
- the byte to be processed.out
- the output buffer the processed byte goes into.outOff
- the offset into the output byte array the processed data starts at.
- the number of bytes written to out.
processBytes
public int processBytes(byte[] in,
int inOff,
int len,
byte[] out,
int outOff)
throws DataLengthException
process a block of bytes from in putting the result into out.
- processBytes in interface AEADBlockCipher
in
- the input byte array.inOff
- the offset into the in array where the data to be processed starts.len
- the number of bytes to be processed.out
- the output buffer the processed bytes go into.outOff
- the offset into the output byte array the processed data starts at.
- the number of bytes written to out.
reset
public void reset()
Reset the cipher. After resetting the cipher is in the same state
as it was after the last init (if there was one).
- reset in interface AEADBlockCipher