ch.epfl.dedis.lib.crypto

Class BlsSig

java.lang.Object

ch.epfl.dedis.lib.crypto.BlsSig

public class BlsSig
extends Object

Class that represents a BLS signature.

Constructor Summary

Constructors

Constructor and Description
BlsSig(byte[] sig) Constructor from an existing signature.
BlsSig(byte[] msg, Scalar x) Constructor that creates a BLS signature S = x * H(m) on a message m using the private key x.

Method Summary

Modifier and Type	Method and Description
byte[]	getSig() Getter for the signature in byte representation.
boolean	verify(byte[] msg, Bn256G2Point X) Verify checks the given BLS signature S on the message m using the public key X by verifying that the equality e(H(m), X) == e(H(m), x*B2) == e(x*H(m), B2) == e(S, B2) holds where e is the pairing operation and B2 is the base point from curve G2.

Methods inherited from class java.lang.Object

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

Constructor Detail

BlsSig

public BlsSig(byte[] sig)

Constructor from an existing signature.

Parameters:

sig - is the signature

BlsSig

public BlsSig(byte[] msg,
              Scalar x)

Constructor that creates a BLS signature S = x * H(m) on a message m using the private key x. The signature S is a point on curve G1.

Parameters:

msg - is the message to be signed.

x - is the secret.

Method Detail

verify

public boolean verify(byte[] msg,
                      Bn256G2Point X)

Verify checks the given BLS signature S on the message m using the public key X by verifying that the equality e(H(m), X) == e(H(m), x*B2) == e(x*H(m), B2) == e(S, B2) holds where e is the pairing operation and B2 is the base point from curve G2.

Parameters:

msg - the signed message .

X - the public key.

Returns:

true if the verification is successful.

getSig

public byte[] getSig()

Getter for the signature in byte representation.