Class Poly1305

  • All Implemented Interfaces:
    Mac

    public class Poly1305
    extends Object
    implements Mac
    Poly1305 message authentication code, designed by D. J. Bernstein.

    Poly1305 computes a 128-bit (16 bytes) authenticator, using a 128 bit nonce and a 256 bit key consisting of a 128 bit key applied to an underlying cipher, and a 128 bit key (with 106 effective key bits) used in the authenticator.

    The polynomial calculation in this implementation is adapted from the public domain poly1305-donna-unrolled C implementation by Andrew M (@floodyberry).

    See Also:
    Poly1305KeyGenerator
    • Constructor Detail

      • Poly1305

        public Poly1305()
        Constructs a Poly1305 MAC, where the key passed to init() will be used directly.
      • Poly1305

        public Poly1305​(BlockCipher cipher)
        Constructs a Poly1305 MAC, using a 128 bit block cipher.
    • Method Detail

      • getAlgorithmName

        public String getAlgorithmName()
        Description copied from interface: Mac
        Return the name of the algorithm the MAC implements.
        Specified by:
        getAlgorithmName in interface Mac
        Returns:
        the name of the algorithm the MAC implements.
      • getMacSize

        public int getMacSize()
        Description copied from interface: Mac
        Return the block size for this MAC (in bytes).
        Specified by:
        getMacSize in interface Mac
        Returns:
        the block size for this MAC in bytes.
      • update

        public void update​(byte in)
                    throws IllegalStateException
        Description copied from interface: Mac
        add a single byte to the mac for processing.
        Specified by:
        update in interface Mac
        Parameters:
        in - the byte to be processed.
        Throws:
        IllegalStateException - if the MAC is not initialised.
      • doFinal

        public int doFinal​(byte[] out,
                           int outOff)
                    throws DataLengthException,
                           IllegalStateException
        Description copied from interface: Mac
        Compute the final stage of the MAC writing the output to the out parameter.

        doFinal leaves the MAC in the same state it was after the last init.

        Specified by:
        doFinal in interface Mac
        Parameters:
        out - the array the MAC is to be output to.
        outOff - the offset into the out buffer the output is to start at.
        Throws:
        DataLengthException - if there isn't enough space in out.
        IllegalStateException - if the MAC is not initialised.
      • reset

        public void reset()
        Description copied from interface: Mac
        Reset the MAC. At the end of resetting the MAC should be in the in the same state it was after the last init (if there was one).
        Specified by:
        reset in interface Mac