ecdsa.go

/*
Copyright IBM Corp. All Rights Reserved.

SPDX-License-Identifier: Apache-2.0
*/

package pkcs11

import (
	"crypto/ecdsa"
	"fmt"

	"github.com/hyperledger/fabric/bccsp"
	"github.com/hyperledger/fabric/bccsp/utils"
)

func (csp *impl) signECDSA(k ecdsaPrivateKey, digest []byte, opts bccsp.SignerOpts) ([]byte, error) {
	r, s, err := csp.signP11ECDSA(k.ski, digest)
	if err != nil {
		return nil, err
	}

	s, err = utils.ToLowS(k.pub.pub, s)
	if err != nil {
		return nil, err
	}

	return utils.MarshalECDSASignature(r, s)
}

func (csp *impl) verifyECDSA(k ecdsaPublicKey, signature, digest []byte, opts bccsp.SignerOpts) (bool, error) {
	r, s, err := utils.UnmarshalECDSASignature(signature)
	if err != nil {
		return false, fmt.Errorf("Failed unmashalling signature [%s]", err)
	}

	lowS, err := utils.IsLowS(k.pub, s)
	if err != nil {
		return false, err
	}

	if !lowS {
		return false, fmt.Errorf("Invalid S. Must be smaller than half the order [%s][%s]", s, utils.GetCurveHalfOrdersAt(k.pub.Curve))
	}

	if csp.softVerify {
		return ecdsa.Verify(k.pub, digest, r, s), nil
	}
	return csp.verifyP11ECDSA(k.ski, digest, r, s, k.pub.Curve.Params().BitSize/8)

}