forked from TrueCloudLab/frostfs-sdk-go
126 lines
3.1 KiB
Go
126 lines
3.1 KiB
Go
package frostfsecdsa
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import (
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"crypto/ecdsa"
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"crypto/elliptic"
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"crypto/sha256"
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"crypto/sha512"
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"fmt"
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"math/big"
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"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
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)
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// PublicKey is a wrapper over ecdsa.PublicKey used for NeoFS needs.
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// Provides frostfscrypto.PublicKey interface.
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//
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// Instances MUST be initialized from ecdsa.PublicKey using type conversion.
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type PublicKey ecdsa.PublicKey
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// MaxEncodedSize returns size of the compressed ECDSA public key.
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func (x PublicKey) MaxEncodedSize() int {
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return 33
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}
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// Encode encodes ECDSA public key in compressed form into buf.
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// Uses exactly MaxEncodedSize bytes of the buf.
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//
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// Encode panics if buf length is less than MaxEncodedSize.
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//
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// See also Decode.
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func (x PublicKey) Encode(buf []byte) int {
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if len(buf) < 33 {
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panic(fmt.Sprintf("too short buffer %d", len(buf)))
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}
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return copy(buf, (*keys.PublicKey)(&x).Bytes())
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}
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// Decode decodes compressed binary representation of the PublicKey.
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//
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// See also Encode.
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func (x *PublicKey) Decode(data []byte) error {
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pub, err := keys.NewPublicKeyFromBytes(data, elliptic.P256())
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if err != nil {
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return err
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}
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*x = (PublicKey)(*pub)
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return nil
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}
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// similar to elliptic.Unmarshal but without IsOnCurve check.
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func unmarshalXY(data []byte) (x *big.Int, y *big.Int) {
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if len(data) != 65 {
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return
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} else if data[0] != 4 { // uncompressed form
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return
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}
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p := elliptic.P256().Params().P
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x = new(big.Int).SetBytes(data[1:33])
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y = new(big.Int).SetBytes(data[33:])
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if x.Cmp(p) >= 0 || y.Cmp(p) >= 0 {
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x, y = nil, nil
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}
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return
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}
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// Verify verifies data signature calculated by ECDSA algorithm with SHA-512 hashing.
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func (x PublicKey) Verify(data, signature []byte) bool {
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h := sha512.Sum512(data)
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r, s := unmarshalXY(signature)
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return r != nil && s != nil && ecdsa.Verify((*ecdsa.PublicKey)(&x), h[:], r, s)
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}
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// PublicKeyRFC6979 is a wrapper over ecdsa.PublicKey used for NeoFS needs.
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// Provides frostfscrypto.PublicKey interface.
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//
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// Instances MUST be initialized from ecdsa.PublicKey using type conversion.
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type PublicKeyRFC6979 ecdsa.PublicKey
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// MaxEncodedSize returns size of the compressed ECDSA public key.
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func (x PublicKeyRFC6979) MaxEncodedSize() int {
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return 33
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}
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// Encode encodes ECDSA public key in compressed form into buf.
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// Uses exactly MaxEncodedSize bytes of the buf.
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//
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// Encode panics if buf length is less than MaxEncodedSize.
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//
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// See also Decode.
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func (x PublicKeyRFC6979) Encode(buf []byte) int {
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if len(buf) < 33 {
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panic(fmt.Sprintf("too short buffer %d", len(buf)))
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}
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return copy(buf, (*keys.PublicKey)(&x).Bytes())
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}
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// Decode decodes binary representation of the ECDSA public key.
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//
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// See also Encode.
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func (x *PublicKeyRFC6979) Decode(data []byte) error {
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pub, err := keys.NewPublicKeyFromBytes(data, elliptic.P256())
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if err != nil {
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return err
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}
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*x = (PublicKeyRFC6979)(*pub)
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return nil
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}
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// Verify verifies data signature calculated by deterministic ECDSA algorithm
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// with SHA-256 hashing.
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//
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// See also RFC 6979.
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func (x PublicKeyRFC6979) Verify(data, signature []byte) bool {
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h := sha256.Sum256(data)
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return (*keys.PublicKey)(&x).Verify(signature, h[:])
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}
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