Package org.bouncycastle.crypto.signers

Class ECNRSigner

  • All Implemented Interfaces:
    DSA, DSAExt
    public class ECNRSigner
extends java.lang.Object
implements DSAExt
    EC-NR as described in IEEE 1363-2000 - a signature algorithm for Elliptic Curve which also offers message recovery.

    • Constructor Summary

      Constructors 
      Constructor Description
      ECNRSigner()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.math.BigInteger[] generateSignature​(byte[] digest)
      generate a signature for the given message using the key we were initialised with.
      java.math.BigInteger getOrder()
      Get the order of the group that the r, s values in signatures belong to.
      byte[] getRecoveredMessage​(java.math.BigInteger r, java.math.BigInteger s)
      Returns the data used for the signature generation, assuming the public key passed to init() is correct.
      void init​(boolean forSigning, CipherParameters param)
      Initialise the signer.
      boolean verifySignature​(byte[] digest, java.math.BigInteger r, java.math.BigInteger s)
      return true if the value r and s represent a signature for the message passed in.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • ECNRSigner

        public ECNRSigner()

    • Method Detail

      • init

        public void init​(boolean forSigning,
                 CipherParameters param)
        Initialise the signer.
        Specified by:
        init in interface DSA
        Parameters:
        forSigning - true if we are generating a signature, false for verification or if we want to use the signer for message recovery.
        param - key parameters for signature generation.

      • getOrder

        public java.math.BigInteger getOrder()
        Description copied from interface: DSAExt
        Get the order of the group that the r, s values in signatures belong to.
        Specified by:
        getOrder in interface DSAExt

      • generateSignature

        public java.math.BigInteger[] generateSignature​(byte[] digest)
        generate a signature for the given message using the key we were initialised with. Generally, the order of the curve should be at least as long as the hash of the message of interest, and with ECNR it *must* be at least as long.
        Specified by:
        generateSignature in interface DSA
        Parameters:
        digest - the digest to be signed.
        Returns:
        two big integers representing the r and s values respectively.
        Throws:
        DataLengthException - if the digest is longer than the key allows

      • verifySignature

        public boolean verifySignature​(byte[] digest,
                               java.math.BigInteger r,
                               java.math.BigInteger s)
        return true if the value r and s represent a signature for the message passed in. Generally, the order of the curve should be at least as long as the hash of the message of interest, and with ECNR, it *must* be at least as long. But just in case the signer applied mod(n) to the longer digest, this implementation will apply mod(n) during verification.
        Specified by:
        verifySignature in interface DSA
        Parameters:
        digest - the digest to be verified.
        r - the r value of the signature.
        s - the s value of the signature.
        Throws:
        DataLengthException - if the digest is longer than the key allows

      • getRecoveredMessage

        public byte[] getRecoveredMessage​(java.math.BigInteger r,
                                  java.math.BigInteger s)
        Returns the data used for the signature generation, assuming the public key passed to init() is correct.
        Returns:
        null if r and s are not valid.