org.bouncycastle.crypto.modes
Class CCMBlockCipher

java.lang.Object
  org.bouncycastle.crypto.modes.CCMBlockCipher

All Implemented Interfaces:

AEADBlockCipher

public class CCMBlockCipher
extends java.lang.Object
implements AEADBlockCipher

Implements the Counter with Cipher Block Chaining mode (CCM) detailed in NIST Special Publication 800-38C.

Note: this mode is a packet mode - it needs all the data up front.

Field Summary

private byte[]	associatedText
private int	blockSize
private BlockCipher	cipher
private java.io.ByteArrayOutputStream	data
private boolean	forEncryption
private CipherParameters	keyParam
private byte[]	macBlock
private int	macSize
private byte[]	nonce

Constructor Summary

CCMBlockCipher(BlockCipher c)
Basic constructor.

Method Summary

private int	calculateMac(byte[] data, int dataOff, int dataLen, byte[] macBlock)
int	doFinal(byte[] out, int outOff) Finish the operation either appending or verifying the MAC at the end of the data.
java.lang.String	getAlgorithmName() Return the name of the algorithm.
byte[]	getMac() Returns a byte array containing the mac calculated as part of the last encrypt or decrypt operation.
int	getOutputSize(int len) return the size of the output buffer required for a processBytes plus a doFinal with an input of len bytes.
BlockCipher	getUnderlyingCipher() return the underlying block cipher that we are wrapping.
int	getUpdateOutputSize(int len) return the size of the output buffer required for a processBytes an input of len bytes.
private boolean	hasAssociatedText()
void	init(boolean forEncryption, CipherParameters params) initialise the underlying cipher.
int	processByte(byte in, byte[] out, int outOff) encrypt/decrypt a single byte.
int	processBytes(byte[] in, int inOff, int inLen, byte[] out, int outOff) process a block of bytes from in putting the result into out.
byte[]	processPacket(byte[] in, int inOff, int inLen)
void	reset() Reset the cipher.

Methods inherited from class java.lang.Object

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

Field Detail

cipher

private BlockCipher cipher

blockSize

private int blockSize

forEncryption

private boolean forEncryption

nonce

private byte[] nonce

associatedText

private byte[] associatedText

macSize

private int macSize

keyParam

private CipherParameters keyParam

macBlock

private byte[] macBlock

data

private java.io.ByteArrayOutputStream data

Constructor Detail

CCMBlockCipher

public CCMBlockCipher(BlockCipher c)

Basic constructor.

Parameters:

c - the block cipher to be used.

Method Detail

getUnderlyingCipher

public BlockCipher getUnderlyingCipher()

return the underlying block cipher that we are wrapping.

Specified by:

getUnderlyingCipher in interface AEADBlockCipher

Returns:

the underlying block cipher that we are wrapping.

init

public void init(boolean forEncryption,
                 CipherParameters params)
          throws java.lang.IllegalArgumentException

Description copied from interface: AEADBlockCipher

initialise the underlying cipher. Parameter can either be an AEADParameters or a ParametersWithIV object.

Specified by:

init in interface AEADBlockCipher

Parameters:

forEncryption - true if we are setting up for encryption, false otherwise.

params - the necessary parameters for the underlying cipher to be initialised.

Throws:

java.lang.IllegalArgumentException - if the params argument is inappropriate.

getAlgorithmName

public java.lang.String getAlgorithmName()

Description copied from interface: AEADBlockCipher

Return the name of the algorithm.

Specified by:

getAlgorithmName in interface AEADBlockCipher

Returns:

the algorithm name.

processByte

public int processByte(byte in,
                       byte[] out,
                       int outOff)
                throws DataLengthException,
                       java.lang.IllegalStateException

Description copied from interface: AEADBlockCipher

encrypt/decrypt a single byte.

Specified by:

processByte in interface AEADBlockCipher

Parameters:

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.

Returns:

the number of bytes written to out.

Throws:

DataLengthException - if the output buffer is too small.

java.lang.IllegalStateException

processBytes

public int processBytes(byte[] in,
                        int inOff,
                        int inLen,
                        byte[] out,
                        int outOff)
                 throws DataLengthException,
                        java.lang.IllegalStateException

Description copied from interface: AEADBlockCipher

process a block of bytes from in putting the result into out.

Specified by:

processBytes in interface AEADBlockCipher

Parameters:

in - the input byte array.

inOff - the offset into the in array where the data to be processed starts.

inLen - 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.

Returns:

the number of bytes written to out.

Throws:

DataLengthException - if the output buffer is too small.

java.lang.IllegalStateException

doFinal

public int doFinal(byte[] out,
                   int outOff)
            throws java.lang.IllegalStateException,
                   InvalidCipherTextException

Description copied from interface: AEADBlockCipher

Finish the operation either appending or verifying the MAC at the end of the data.

Specified by:

doFinal in interface AEADBlockCipher

Parameters:

out - space for any resulting output data.

outOff - offset into out to start copying the data at.

Returns:

number of bytes written into out.

Throws:

java.lang.IllegalStateException - if the cipher is in an inappropriate state.

InvalidCipherTextException - if the MAC fails to match.

reset

public void reset()

Description copied from interface: AEADBlockCipher

Reset the cipher. After resetting the cipher is in the same state as it was after the last init (if there was one).

Specified by:

reset in interface AEADBlockCipher

getMac

public byte[] getMac()

Returns a byte array containing the mac calculated as part of the last encrypt or decrypt operation.

Specified by:

getMac in interface AEADBlockCipher

Returns:

the last mac calculated.

getUpdateOutputSize

public int getUpdateOutputSize(int len)

Description copied from interface: AEADBlockCipher

return the size of the output buffer required for a processBytes an input of len bytes.

Specified by:

getUpdateOutputSize in interface AEADBlockCipher

Parameters:

len - the length of the input.

Returns:

the space required to accommodate a call to processBytes with len bytes of input.

getOutputSize

public int getOutputSize(int len)

Description copied from interface: AEADBlockCipher

return the size of the output buffer required for a processBytes plus a doFinal with an input of len bytes.

Specified by:

getOutputSize in interface AEADBlockCipher

Parameters:

len - the length of the input.

Returns:

the space required to accommodate a call to processBytes and doFinal with len bytes of input.

processPacket

public byte[] processPacket(byte[] in,
                            int inOff,
                            int inLen)
                     throws java.lang.IllegalStateException,
                            InvalidCipherTextException

Throws:

java.lang.IllegalStateException

InvalidCipherTextException

calculateMac

private int calculateMac(byte[] data,
                         int dataOff,
                         int dataLen,
                         byte[] macBlock)

hasAssociatedText

private boolean hasAssociatedText()