Package org.bouncycastle.crypto.signers

Class BLSSigner

  • All Implemented Interfaces:
    Signer
    public class BLSSigner
extends java.lang.Object
implements Signer
    Generic BLS12-381 signer implementing the BC Signer interface.

    Signs and verifies under a configurable BLS hash-to-curve domain separation tag, defaulting to the BasicScheme DST BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_. The BLSSigner(byte[]) constructor lets callers select the ProofOfPossession DST (BLS12_381ProofOfPossession.DST) for Eth2 interop, or supply any other RFC 9380 DST.

    Note that the MessageAugmentation suite is intentionally NOT supported here, since its hash input is pk || msg — the pubkey must be available at sign time, which doesn't fit the Signer "sk + buffered message" contract cleanly. Callers wanting AUG should use BLS12_381MessageAugmentation directly.

    Produces and accepts 96-byte Zcash-format compressed G2 signatures, the same encoding used by Eth2 / IETF draft-irtf-cfrg-bls-signature.

    • Constructor Summary

      Constructors 
      Constructor Description
      BLSSigner()
      Construct a signer with the BasicScheme DST (BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_).
      BLSSigner​(byte[] dst)
      Construct a signer with an explicit hash-to-curve DST.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      byte[] generateSignature()
      generate a signature for the message we've been loaded with using the key we were initialised with.
      void init​(boolean forSigning, CipherParameters param)
      Initialise the signer for signing or verification.
      void reset()
      reset the internal state
      void update​(byte b)
      update the internal digest with the byte b
      void update​(byte[] in, int off, int len)
      update the internal digest with the byte array in
      boolean verifySignature​(byte[] signature)
      return true if the internal state represents the signature described in the passed in array.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • BLSSigner

        public BLSSigner()
        Construct a signer with the BasicScheme DST (BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_).

      • BLSSigner

        public BLSSigner​(byte[] dst)
        Construct a signer with an explicit hash-to-curve DST. For Eth2 interop pass BLS12_381ProofOfPossession.DST.

    • Method Detail

      • init

        public void init​(boolean forSigning,
                 CipherParameters param)
        Description copied from interface: Signer
        Initialise the signer for signing or verification.
        Specified by:
        init in interface Signer
        Parameters:
        forSigning - true if for signing, false otherwise
        param - necessary parameters.

      • update

        public void update​(byte b)
        Description copied from interface: Signer
        update the internal digest with the byte b
        Specified by:
        update in interface Signer

      • update

        public void update​(byte[] in,
                   int off,
                   int len)
        Description copied from interface: Signer
        update the internal digest with the byte array in
        Specified by:
        update in interface Signer

      • generateSignature

        public byte[] generateSignature()
                         throws CryptoException
        Description copied from interface: Signer
        generate a signature for the message we've been loaded with using the key we were initialised with.
        Specified by:
        generateSignature in interface Signer
        Throws:
        CryptoException

      • verifySignature

        public boolean verifySignature​(byte[] signature)
        Description copied from interface: Signer
        return true if the internal state represents the signature described in the passed in array.
        Specified by:
        verifySignature in interface Signer

      • reset

        public void reset()
        Description copied from interface: Signer
        reset the internal state
        Specified by:
        reset in interface Signer