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[#190] crypto/ecdsa: Use separate types for RFC-6979 signature algo

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Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
This commit is contained in:
Leonard Lyubich 2022-04-19 11:11:29 +03:00 • committed by LeL
parent 7fe75d2cd9
commit 9f20d74d76
9 changed files with 105 additions and 124 deletions
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89
crypto/ecdsa/public.go
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@ -11,28 +11,11 @@ import (
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
)
// PublicKey implements neofscrypto.PublicKey based on ECDSA.
// PublicKey is a wrapper over ecdsa.PublicKey used for NeoFS needs.
// Provides neofscrypto.PublicKey interface.
//
// Supported schemes:
// - neofscrypto.ECDSA_SHA512 (default)
// - neofscrypto.ECDSA_DETERMINISTIC_SHA256
type PublicKey struct {
deterministic bool
key ecdsa.PublicKey
}
// SetKey specifies ecdsa.PublicKey to be used for ECDSA signature verification.
func (x *PublicKey) SetKey(key ecdsa.PublicKey) {
x.key = key
}
// MakeDeterministic makes PublicKey to use Deterministic ECDSA scheme
// (see neofscrypto.ECDSA_DETERMINISTIC_SHA256). By default,
// neofscrypto.ECDSA_SHA512 is used.
func (x *PublicKey) MakeDeterministic() {
x.deterministic = true
}
// Instances MUST be initialized from ecdsa.PublicKey using type conversion.
type PublicKey ecdsa.PublicKey
// MaxEncodedSize returns size of the compressed ECDSA public key.
func (x PublicKey) MaxEncodedSize() int {
@ -50,7 +33,7 @@ func (x PublicKey) Encode(buf []byte) int {
panic(fmt.Sprintf("too short buffer %d", len(buf)))
}
return copy(buf, (*keys.PublicKey)(&x.key).Bytes())
return copy(buf, (*keys.PublicKey)(&x).Bytes())
}
// Decode decodes compressed binary representation of the PublicKey.
@ -62,7 +45,7 @@ func (x *PublicKey) Decode(data []byte) error {
return err
}
x.key = (ecdsa.PublicKey)(*pub)
*x = (PublicKey)(*pub)
return nil
}
@ -86,18 +69,58 @@ func unmarshalXY(data []byte) (x *big.Int, y *big.Int) {
return
}
// Verify verifies data signature calculated by algorithm depending on
// PublicKey state:
// - Deterministic ECDSA with SHA-256 hashing if MakeDeterministic called
// - ECDSA with SHA-512 hashing, otherwise
// Verify verifies data signature calculated by ECDSA algorithm with SHA-512 hashing.
func (x PublicKey) Verify(data, signature []byte) bool {
if x.deterministic {
h := sha256.Sum256(data)
return (*keys.PublicKey)(&x.key).Verify(signature, h[:])
}
h := sha512.Sum512(data)
r, s := unmarshalXY(signature)
return r != nil && s != nil && ecdsa.Verify(&x.key, h[:], r, s)
return r != nil && s != nil && ecdsa.Verify((*ecdsa.PublicKey)(&x), h[:], r, s)
}
// PublicKeyRFC6979 is a wrapper over ecdsa.PublicKey used for NeoFS needs.
// Provides neofscrypto.PublicKey interface.
//
// Instances MUST be initialized from ecdsa.PublicKey using type conversion.
type PublicKeyRFC6979 ecdsa.PublicKey
// MaxEncodedSize returns size of the compressed ECDSA public key.
func (x PublicKeyRFC6979) MaxEncodedSize() int {
return 33
}
// Encode encodes ECDSA public key in compressed form into buf.
// Uses exactly MaxEncodedSize bytes of the buf.
//
// Encode panics if buf length is less than MaxEncodedSize.
//
// See also Decode.
func (x PublicKeyRFC6979) Encode(buf []byte) int {
if len(buf) < 33 {
panic(fmt.Sprintf("too short buffer %d", len(buf)))
}
return copy(buf, (*keys.PublicKey)(&x).Bytes())
}
// Decode decodes binary representation of the ECDSA public key.
//
// See also Encode.
func (x *PublicKeyRFC6979) Decode(data []byte) error {
pub, err := keys.NewPublicKeyFromBytes(data, elliptic.P256())
if err != nil {
return err
}
*x = (PublicKeyRFC6979)(*pub)
return nil
}
// Verify verifies data signature calculated by deterministic ECDSA algorithm
// with SHA-256 hashing.
//
// See also RFC 6979.
func (x PublicKeyRFC6979) Verify(data, signature []byte) bool {
h := sha256.Sum256(data)
return (*keys.PublicKey)(&x).Verify(signature, h[:])
}