frostfs-api-go/util/signature/walletconnect/sign.go

143 lines
4.1 KiB
Go
Raw Normal View History

package walletconnect
import (
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"encoding/binary"
"encoding/hex"
crypto "git.frostfs.info/TrueCloudLab/frostfs-crypto"
)
const (
// saltSize is the salt size added to signed message.
saltSize = 16
// signatureLen is the length of RFC6979 signature.
signatureLen = 64
)
// SignedMessage contains mirrors `SignedMessage` struct from the WalletConnect API.
// https://neon.coz.io/wksdk/core/modules.html#SignedMessage
type SignedMessage struct {
Data []byte
Message []byte
PublicKey []byte
Salt []byte
}
// Sign signs message using WalletConnect API. The returned signature
// contains RFC6979 signature and 16-byte salt.
func Sign(p *ecdsa.PrivateKey, msg []byte) ([]byte, error) {
sm, err := SignMessage(p, msg)
if err != nil {
return nil, err
}
return append(sm.Data, sm.Salt...), nil
}
// Verify verifies message using WalletConnect API.
func Verify(p *ecdsa.PublicKey, data, sign []byte) bool {
if len(sign) != signatureLen+saltSize {
return false
}
salt := sign[signatureLen:]
return VerifyMessage(p, SignedMessage{
Data: sign[:signatureLen],
Message: createMessageWithSalt(data, salt),
Salt: salt,
})
}
// SignMessage signs message with a private key and returns structure similar to
// `signMessage` of the WalletConnect API.
// https://github.com/CityOfZion/wallet-connect-sdk/blob/89c236b/packages/wallet-connect-sdk-core/src/index.ts#L496
// https://github.com/CityOfZion/neon-wallet/blob/1174a9388480e6bbc4f79eb13183c2a573f67ca8/app/context/WalletConnect/helpers.js#L133
func SignMessage(p *ecdsa.PrivateKey, msg []byte) (SignedMessage, error) {
var salt [saltSize]byte
_, _ = rand.Read(salt[:])
msg = createMessageWithSalt(msg, salt[:])
sign, err := crypto.SignRFC6979(p, msg)
if err != nil {
return SignedMessage{}, err
}
return SignedMessage{
Data: sign,
Message: msg,
PublicKey: elliptic.MarshalCompressed(p.Curve, p.X, p.Y),
Salt: salt[:],
}, nil
}
// VerifyMessage verifies message with a private key and returns structure similar to
// `verifyMessage` of WalletConnect API.
// https://github.com/CityOfZion/wallet-connect-sdk/blob/89c236b/packages/wallet-connect-sdk-core/src/index.ts#L515
// https://github.com/CityOfZion/neon-wallet/blob/1174a9388480e6bbc4f79eb13183c2a573f67ca8/app/context/WalletConnect/helpers.js#L147
func VerifyMessage(p *ecdsa.PublicKey, m SignedMessage) bool {
if p == nil {
x, y := elliptic.UnmarshalCompressed(elliptic.P256(), m.PublicKey)
if x == nil || y == nil {
return false
}
p = &ecdsa.PublicKey{
Curve: elliptic.P256(),
X: x,
Y: y,
}
}
return crypto.VerifyRFC6979(p, m.Message, m.Data) == nil
}
func createMessageWithSalt(msg, salt []byte) []byte {
// 4 byte prefix + length of the message with salt in bytes +
// + salt + message + 2 byte postfix.
saltedLen := hex.EncodedLen(len(salt)) + len(msg)
data := make([]byte, 4+getVarIntSize(saltedLen)+saltedLen+2)
n := copy(data, []byte{0x01, 0x00, 0x01, 0xf0}) // fixed prefix
n += putVarUint(data[n:], uint64(saltedLen)) // salt is hex encoded, double its size
n += hex.Encode(data[n:], salt[:]) // for some reason we encode salt in hex
n += copy(data[n:], msg)
copy(data[n:], []byte{0x00, 0x00})
return data
}
// Following functions are copied from github.com/nspcc-dev/neo-go/pkg/io package
// to avoid having another dependency.
// getVarIntSize returns the size in number of bytes of a variable integer.
// Reference: https://github.com/neo-project/neo/blob/26d04a642ac5a1dd1827dabf5602767e0acba25c/src/neo/IO/Helper.cs#L131
func getVarIntSize(value int) int {
var size uintptr
if value < 0xFD {
size = 1 // unit8
} else if value <= 0xFFFF {
size = 3 // byte + uint16
} else {
size = 5 // byte + uint32
}
return int(size)
}
// putVarUint puts val in varint form to the pre-allocated buffer.
func putVarUint(data []byte, val uint64) int {
if val < 0xfd {
data[0] = byte(val)
return 1
}
if val <= 0xFFFF {
data[0] = byte(0xfd)
binary.LittleEndian.PutUint16(data[1:], uint16(val))
return 3
}
data[0] = byte(0xfe)
binary.LittleEndian.PutUint32(data[1:], uint32(val))
return 5
}