lbryschema.go/claim/validator.go
2017-11-13 10:11:19 -05:00

99 lines
2.9 KiB
Go

package claim
import (
"../address"
"crypto/sha256"
"errors"
"encoding/asn1"
"crypto/x509/pkix"
"github.com/btcsuite/btcd/btcec"
"math/big"
"crypto/ecdsa"
"encoding/hex"
)
type publicKeyInfo struct {
Raw asn1.RawContent
Algorithm pkix.AlgorithmIdentifier
PublicKey asn1.BitString
}
const SECP256k1 = "SECP256k1"
func GetClaimSignatureDigest(claimAddress [25]byte, certificateId [20]byte, serializedNoSig []byte) [32]byte {
combined := []byte{}
for _, c := range claimAddress {combined = append(combined, c)}
for _, c := range serializedNoSig {combined = append(combined, c)}
for _, c := range certificateId {combined = append(combined, c)}
digest := sha256.Sum256(combined)
return [32]byte(digest)
}
func (claim *ClaimHelper) GetCertificatePublicKey() (*btcec.PublicKey, error) {
derBytes := claim.GetCertificate().GetPublicKey()
pub := publicKeyInfo{}
asn1.Unmarshal(derBytes, &pub)
pubkey_bytes := []byte(pub.PublicKey.Bytes)
p, err := btcec.ParsePubKey(pubkey_bytes, btcec.S256())
if err != nil {
return &btcec.PublicKey{}, err
}
return p, err
}
func (claim *ClaimHelper) VerifyDigest(certificate *ClaimHelper, signature [64]byte, digest [32]byte) bool {
public_key, err := certificate.GetCertificatePublicKey()
if err != nil {
return false
}
if claim.PublisherSignature.SignatureType.String() == SECP256k1 {
R := &big.Int{}
S := &big.Int{}
R.SetBytes(signature[0:32])
S.SetBytes(signature[32:64])
return ecdsa.Verify(public_key.ToECDSA(), digest[:], R, S)
}
return false
}
func (claim *ClaimHelper) ValidateClaimSignatureBytes(certificate *ClaimHelper, claimAddress [25]byte, certificateId [20]byte) (bool, error) {
signature := claim.GetPublisherSignature()
if signature == nil {
return false, errors.New("claim does not have a signature")
}
signatureSlice := signature.GetSignature()
signatureBytes := [64]byte{}
for i := range signatureBytes {
signatureBytes[i] = signatureSlice[i]
}
claimAddress, err := address.ValidateAddress(claimAddress)
if err != nil {
return false, errors.New("invalid address")
}
serializedNoSig, err := claim.SerializedNoSignature()
if err != nil {
return false, errors.New("serialization error")
}
claimDigest := GetClaimSignatureDigest(claimAddress, certificateId, serializedNoSig)
return claim.VerifyDigest(certificate, signatureBytes, claimDigest), nil
}
func (claim *ClaimHelper) ValidateClaimSignature(certificate *ClaimHelper, claimAddress string, certificateId string) (bool, error) {
addressBytes, err := address.DecodeAddress(claimAddress)
if err != nil {
return false, err
}
certificateIdSlice, err := hex.DecodeString(certificateId)
if err != nil {
return false, err
}
certificateIdBytes := [20]byte{}
for i := range certificateIdBytes {
certificateIdBytes[i] = certificateIdSlice[i]
}
return claim.ValidateClaimSignatureBytes(certificate, addressBytes, certificateIdBytes)
}