Golang Point.Equal方法代码示例

// Verifies that the 'message' is included in the signature and that it
// is correct.
// Message is your own hash, and reply contains the inclusion proof + signature
// on the aggregated message
func VerifySignature(suite abstract.Suite, reply *StampSignature, public abstract.Point, message []byte) bool {
	// Check if aggregate public key is correct
	if !public.Equal(reply.AggPublic) {
		dbg.Lvl1("Aggregate-public-key check: FAILED (maybe you have an outdated config file of the tree)")
		return false
	}
	// First check if the challenge is ok
	if err := VerifyChallenge(suite, reply); err != nil {
		dbg.Lvl1("Challenge-check: FAILED (", err, ")")
		return false
	}
	dbg.Lvl2("Challenge-check: OK")

	// Incorporate the timestamp in the message since the verification process
	// is done by reconstructing the challenge
	var b bytes.Buffer
	if err := binary.Write(&b, binary.LittleEndian, reply.Timestamp); err != nil {
		dbg.Lvl1("Error marshaling the timestamp for signature verification")
		return false
	}
	msg := append(b.Bytes(), []byte(reply.MerkleRoot)...)
	if err := VerifySchnorr(suite, msg, public, reply.Challenge, reply.Response); err != nil {
		dbg.Lvl1("Signature-check: FAILED (", err, ")")
		return false
	}
	dbg.Lvl2("Signature-check: OK")

	// finally check the proof
	if !proof.CheckProof(suite.Hash, reply.MerkleRoot, hashid.HashId(message), reply.Prf) {
		dbg.Lvl2("Inclusion-check: FAILED")
		return false
	}
	dbg.Lvl2("Inclusion-check: OK")
	return true
}

// Pick a [pseudo-]random curve point with optional embedded data,
// filling in the point's x,y coordinates
// and returning any remaining data not embedded.
func (c *curve) pickPoint(P point, data []byte, rand cipher.Stream) []byte {

	// How much data to embed?
	dl := c.pickLen()
	if dl > len(data) {
		dl = len(data)
	}

	// Retry until we find a valid point
	var x, y nist.Int
	var Q abstract.Point
	for {
		// Get random bits the size of a compressed Point encoding,
		// in which the topmost bit is reserved for the x-coord sign.
		l := c.PointLen()
		b := make([]byte, l)
		rand.XORKeyStream(b, b) // Interpret as little-endian
		if data != nil {
			b[0] = byte(dl)       // Encode length in low 8 bits
			copy(b[1:1+dl], data) // Copy in data to embed
		}
		util.Reverse(b, b) // Convert to big-endian form

		xsign := b[0] >> 7                    // save x-coordinate sign bit
		b[0] &^= 0xff << uint(c.P.BitLen()&7) // clear high bits

		y.M = &c.P // set y-coordinate
		y.SetBytes(b)

		if !c.solveForX(&x, &y) { // Corresponding x-coordinate?
			continue // none, retry
		}

		// Pick a random sign for the x-coordinate
		if c.coordSign(&x) != uint(xsign) {
			x.Neg(&x)
		}

		// Initialize the point
		P.initXY(&x.V, &y.V, c.self)
		if c.full {
			// If we're using the full group,
			// we just need any point on the curve, so we're done.
			return data[dl:]
		}

		// We're using the prime-order subgroup,
		// so we need to make sure the point is in that subgroup.
		// If we're not trying to embed data,
		// we can convert our point into one in the subgroup
		// simply by multiplying it by the cofactor.
		if data == nil {
			P.Mul(P, &c.cofact) // multiply by cofactor
			if P.Equal(c.null) {
				continue // unlucky; try again
			}
			return data[dl:]
		}

		// Since we need the point's y-coordinate to make sense,
		// we must simply check if the point is in the subgroup
		// and retry point generation until it is.
		if Q == nil {
			Q = c.self.Point()
		}
		Q.Mul(P, &c.order)
		if Q.Equal(c.null) {
			return data[dl:]
		}

		// Keep trying...
	}
}

// Simple helper to verify Theta elements,
// by checking whether A^a*B^-b = T.
// P,Q,s are simply "scratch" abstract.Point/Scalars reused for efficiency.
func thver(A, B, T, P, Q abstract.Point, a, b, s abstract.Scalar) bool {
	P.Mul(A, a)
	Q.Mul(B, s.Neg(b))
	P.Add(P, Q)
	return P.Equal(T)
}