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author | Felix Lange <fjl@users.noreply.github.com> | 2017-12-06 23:07:08 +0800 |
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committer | GitHub <noreply@github.com> | 2017-12-06 23:07:08 +0800 |
commit | e85b68ef53e80eb66c7ab394c57e9eb146a60b91 (patch) | |
tree | 92a728f14c9a0d42b50f2410d3c67a46795364d6 /crypto/signature_nocgo.go | |
parent | 6e613cf3de6ebfd14edd5a332baf6e4079c1c86f (diff) | |
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crypto: add DecompressPubkey, VerifySignature (#15615)
We need those operations for p2p/enr.
Also upgrade github.com/btcsuite/btcd/btcec to the latest version
and improve BenchmarkSha3. The benchmark printed extra output
that confused tools like benchstat and ignored N.
Diffstat (limited to 'crypto/signature_nocgo.go')
-rw-r--r-- | crypto/signature_nocgo.go | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/crypto/signature_nocgo.go b/crypto/signature_nocgo.go index a022eef9a..17fd613b2 100644 --- a/crypto/signature_nocgo.go +++ b/crypto/signature_nocgo.go @@ -21,11 +21,14 @@ package crypto import ( "crypto/ecdsa" "crypto/elliptic" + "errors" "fmt" + "math/big" "github.com/btcsuite/btcd/btcec" ) +// Ecrecover returns the uncompressed public key that created the given signature. func Ecrecover(hash, sig []byte) ([]byte, error) { pub, err := SigToPub(hash, sig) if err != nil { @@ -35,6 +38,7 @@ func Ecrecover(hash, sig []byte) ([]byte, error) { return bytes, err } +// SigToPub returns the public key that created the given signature. func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) { // Convert to btcec input format with 'recovery id' v at the beginning. btcsig := make([]byte, 65) @@ -71,6 +75,33 @@ func Sign(hash []byte, prv *ecdsa.PrivateKey) ([]byte, error) { return sig, nil } +// VerifySignature checks that the given public key created signature over hash. +// The public key should be in compressed (33 bytes) or uncompressed (65 bytes) format. +// The signature should have the 64 byte [R || S] format. +func VerifySignature(pubkey, hash, signature []byte) bool { + if len(signature) != 64 { + return false + } + sig := &btcec.Signature{R: new(big.Int).SetBytes(signature[:32]), S: new(big.Int).SetBytes(signature[32:])} + key, err := btcec.ParsePubKey(pubkey, btcec.S256()) + if err != nil { + return false + } + return sig.Verify(hash, key) +} + +// DecompressPubkey parses a public key in the 33-byte compressed format. +func DecompressPubkey(pubkey []byte) (*ecdsa.PublicKey, error) { + if len(pubkey) != 33 { + return nil, errors.New("invalid compressed public key length") + } + key, err := btcec.ParsePubKey(pubkey, btcec.S256()) + if err != nil { + return nil, err + } + return key.ToECDSA(), nil +} + // S256 returns an instance of the secp256k1 curve. func S256() elliptic.Curve { return btcec.S256() |