ECNRSigner (Bouncy Castle Library 1.52 API Specification)
Date: 2015-03-01

org.bouncycastle.crypto.signers

## Class ECNRSigner

- java.lang.Object
- - org.bouncycastle.crypto.signers.ECNRSigner

- All Implemented Interfaces:
    DSA

      public class ECNRSigner
      extends java.lang.Object
      implements DSA

  EC-NR as described in IEEE 1363-2000

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `ECNRSigner()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `java.math.BigInteger[]` | `generateSignature(byte[] digest)` generate a signature for the given message using the key we were initialised with.
    `void` | `init(boolean forSigning, CipherParameters param)` initialise the signer for signature generation or signature verification.
    `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)

      Description copied from interface: `DSA`
      initialise the signer for signature generation or signature verification.
      Specified by:
        `init` in interface `DSA`
      Parameters:
        `forSigning` - true if we are generating a signature, false otherwise.
        `param` - key parameters for signature generation.

    - #### 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