diff --git a/btcec/signature_test.go b/btcec/signature_test.go index a8b3e1e9..a4b86bb8 100644 --- a/btcec/signature_test.go +++ b/btcec/signature_test.go @@ -11,6 +11,7 @@ import ( "encoding/hex" "fmt" "math/big" + "reflect" "testing" ) @@ -523,6 +524,67 @@ func TestSignCompact(t *testing.T) { } } +// recoveryTests assert basic tests for public key recovery from signatures. +// The cases are borrowed from github.com/fjl/btcec-issue. +var recoveryTests = []struct { + msg string + sig string + pub string + err error +}{ + { + // Valid curve point recovered. + msg: "ce0677bb30baa8cf067c88db9811f4333d131bf8bcf12fe7065d211dce971008", + sig: "0190f27b8b488db00b00606796d2987f6a5f59ae62ea05effe84fef5b8b0e549984a691139ad57a3f0b906637673aa2f63d1f55cb1a69199d4009eea23ceaddc93", + pub: "04E32DF42865E97135ACFB65F3BAE71BDC86F4D49150AD6A440B6F15878109880A0A2B2667F7E725CEEA70C673093BF67663E0312623C8E091B13CF2C0F11EF652", + }, + { + // Invalid curve point recovered. + msg: "00c547e4f7b0f325ad1e56f57e26c745b09a3e503d86e00e5255ff7f715d3d1c", + sig: "0100b1693892219d736caba55bdb67216e485557ea6b6af75f37096c9aa6a5a75f00b940b1d03b21e36b0e47e79769f095fe2ab855bd91e3a38756b7d75a9c4549", + err: fmt.Errorf("invalid square root"), + }, + { + // Low R and S values. + msg: "ba09edc1275a285fb27bfe82c4eea240a907a0dbaf9e55764b8f318c37d5974f", + sig: "00000000000000000000000000000000000000000000000000000000000000002c0000000000000000000000000000000000000000000000000000000000000004", + pub: "04A7640409AA2083FDAD38B2D8DE1263B2251799591D840653FB02DBBA503D7745FCB83D80E08A1E02896BE691EA6AFFB8A35939A646F1FC79052A744B1C82EDC3", + }, +} + +func TestRecoverCompact(t *testing.T) { + for i, test := range recoveryTests { + msg := decodeHex(test.msg) + sig := decodeHex(test.sig) + + // Magic DER constant. + sig[0] += 27 + + pub, _, err := RecoverCompact(S256(), sig, msg) + + // Verify that returned error matches as expected. + if !reflect.DeepEqual(test.err, err) { + t.Errorf("unexpected error returned from pubkey "+ + "recovery #%d: wanted %v, got %v", + i, test.err, err) + continue + } + + // If check succeeded because a proper error was returned, we + // ignore the returned pubkey. + if err != nil { + continue + } + + // Otherwise, ensure the correct public key was recovered. + exPub, _ := ParsePubKey(decodeHex(test.pub), S256()) + if !exPub.IsEqual(pub) { + t.Errorf("unexpected recovered public key #%d: "+ + "want %v, got %v", i, exPub, pub) + } + } +} + func TestRFC6979(t *testing.T) { // Test vectors matching Trezor and CoreBitcoin implementations. // - https://github.com/trezor/trezor-crypto/blob/9fea8f8ab377dc514e40c6fd1f7c89a74c1d8dc6/tests.c#L432-L453