org.bouncycastle.crypto.signers

Class BLSSigner

java.lang.Object

org.bouncycastle.crypto.signers.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 and 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

Modifier and Type	Method and 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