Class KCCMBlockCipher

java.lang.Object
org.bouncycastle.crypto.modes.KCCMBlockCipher
All Implemented Interfaces:
AEADBlockCipher, AEADCipher
public class KCCMBlockCipher extends Object implements AEADBlockCipher
Implementation of DSTU7624 CCM mode.

Partial-block / interop caveat: messages whose length is not a multiple of the underlying block size are handled following the generic CCM construction (NIST SP 800-38C / RFC 3610): the CBC-MAC zero-pads the trailing partial block and the counter (gamma) keystream is truncated for the trailing partial block. DSTU 7624:2014 does not publish a partial-block CCM test vector, so this behaviour is verified by round-trip self-consistency only and has not been confirmed against an independent conformant DSTU 7624 implementation. Callers requiring guaranteed interoperability with other DSTU 7624 CCM implementations should restrict input to whole blocks until such a vector is available. See github #287.

  • Constructor Summary

    Constructors
    Constructor
    Description
    KCCMBlockCipher(BlockCipher engine)
    Base constructor.
    KCCMBlockCipher(BlockCipher engine, int nB)
    Constructor allowing Nb configuration.

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    doFinal(byte[] out, int outOff)
    Finish the operation either appending or verifying the MAC at the end of the data.
    String
    getAlgorithmName()
    Return the name of the algorithm.
    byte[]
    getMac()
    Return the value of the MAC associated with the last stream processed.
    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 BlockCipher this object wraps.
    int
    getUpdateOutputSize(int len)
    return the size of the output buffer required for a processBytes an input of len bytes.
    void
    init(boolean forEncryption, CipherParameters params)
    initialise the underlying cipher.
    void
    processAADByte(byte in)
    Add a single byte to the associated data check.
    void
    processAADBytes(byte[] in, int inOff, int len)
    Add a sequence of bytes to the associated data check.
    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.
    int
    processPacket(byte[] in, int inOff, int len, byte[] out, int outOff)
     
    void
    reset()
    Reset the cipher.

    Methods inherited from class Object

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

  • Constructor Details

    • KCCMBlockCipher

      public KCCMBlockCipher(BlockCipher engine)
      Base constructor. Nb value is set to 4.
      Parameters:
      engine - base cipher to use under CCM.

    • KCCMBlockCipher

      public KCCMBlockCipher(BlockCipher engine, int nB)
      Constructor allowing Nb configuration.

      Nb is a parameter specified in CCM mode of DSTU7624 standard. This parameter specifies maximum possible length of input. It should be calculated as follows: Nb = 1/8 * (-3 + log[2]Nmax) + 1, where Nmax - length of input message in bits. For practical reasons Nmax usually less than 4Gb, e.g. for Nmax = 2^32 - 1, Nb = 4.

      Parameters:
      engine - base cipher to use under CCM.
      nB - Nb value to use.

  • Method Details

    • init

      public void init(boolean forEncryption, CipherParameters params) throws IllegalArgumentException
      Description copied from interface: AEADCipher
      initialise the underlying cipher. Parameter can either be an AEADParameters or a ParametersWithIV object.
      Specified by:
      init in interface AEADCipher
      Parameters:
      forEncryption - true if we are setting up for encryption, false otherwise.
      params - the necessary parameters for the underlying cipher to be initialised.
      Throws:
      IllegalArgumentException - if the params argument is inappropriate.

    • getAlgorithmName

      public String getAlgorithmName()
      Description copied from interface: AEADCipher
      Return the name of the algorithm.
      Specified by:
      getAlgorithmName in interface AEADCipher
      Returns:
      the algorithm name.

    • getUnderlyingCipher

      public BlockCipher getUnderlyingCipher()
      Description copied from interface: AEADBlockCipher
      return the BlockCipher this object wraps.
      Specified by:
      getUnderlyingCipher in interface AEADBlockCipher
      Returns:
      the BlockCipher this object wraps.

    • processAADByte

      public void processAADByte(byte in)
      Description copied from interface: AEADCipher
      Add a single byte to the associated data check.
      If the implementation supports it, this will be an online operation and will not retain the associated data.
      Specified by:
      processAADByte in interface AEADCipher
      Parameters:
      in - the byte to be processed.

    • processAADBytes

      public void processAADBytes(byte[] in, int inOff, int len)
      Description copied from interface: AEADCipher
      Add a sequence of bytes to the associated data check.
      If the implementation supports it, this will be an online operation and will not retain the associated data.
      Specified by:
      processAADBytes in interface AEADCipher
      Parameters:
      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.

    • processByte

      public int processByte(byte in, byte[] out, int outOff) throws DataLengthException, IllegalStateException
      Description copied from interface: AEADCipher
      encrypt/decrypt a single byte.
      Specified by:
      processByte in interface AEADCipher
      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.
      IllegalStateException

    • processBytes

      public int processBytes(byte[] in, int inOff, int inLen, byte[] out, int outOff) throws DataLengthException, IllegalStateException
      Description copied from interface: AEADCipher
      process a block of bytes from in putting the result into out.
      Specified by:
      processBytes in interface AEADCipher
      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.
      IllegalStateException

    • processPacket

      public int processPacket(byte[] in, int inOff, int len, byte[] out, int outOff) throws IllegalStateException, InvalidCipherTextException
      Throws:
      IllegalStateException
      InvalidCipherTextException

    • doFinal

      public int doFinal(byte[] out, int outOff) throws IllegalStateException, InvalidCipherTextException
      Description copied from interface: AEADCipher
      Finish the operation either appending or verifying the MAC at the end of the data.
      Specified by:
      doFinal in interface AEADCipher
      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:
      IllegalStateException - if the cipher is in an inappropriate state.
      InvalidCipherTextException - if the MAC fails to match.

    • getMac

      public byte[] getMac()
      Description copied from interface: AEADCipher
      Return the value of the MAC associated with the last stream processed.
      Specified by:
      getMac in interface AEADCipher
      Returns:
      MAC for plaintext data.

    • getUpdateOutputSize

      public int getUpdateOutputSize(int len)
      Description copied from interface: AEADCipher
      return the size of the output buffer required for a processBytes an input of len bytes.

      The returned size may be dependent on the initialisation of this cipher and may not be accurate once subsequent input data is processed - this method should be invoked immediately prior to input data being processed.

      Specified by:
      getUpdateOutputSize in interface AEADCipher
      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: AEADCipher
      return the size of the output buffer required for a processBytes plus a doFinal with an input of len bytes.

      The returned size may be dependent on the initialisation of this cipher and may not be accurate once subsequent input data is processed - this method should be invoked immediately prior to a call to final processing of input data and a call to AEADCipher.doFinal(byte[], int).

      Specified by:
      getOutputSize in interface AEADCipher
      Parameters:
      len - the length of the input.
      Returns:
      the space required to accommodate a call to processBytes and doFinal with len bytes of input.

    • reset

      public void reset()
      Description copied from interface: AEADCipher
      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 AEADCipher