initial addition of essential crypto, encoders, workflows and LLM instructions

pkg/crypto/ec/pubkey.go

@@ -0,0 +1,52 @@
+// Copyright (c) 2013-2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcec
+
+import (
+	"next.orly.dev/pkg/crypto/ec/secp256k1"
+)
+
+// These constants define the lengths of serialized public keys.
+
+const (
+	PubKeyBytesLenCompressed = 33
+)
+
+const (
+	pubkeyCompressed   byte = 0x2 // y_bit + x coord
+	pubkeyUncompressed byte = 0x4 // x coord + y coord
+	pubkeyHybrid       byte = 0x6 // y_bit + x coord + y coord
+)
+
+// IsCompressedPubKey returns true the passed serialized public key has
+// been encoded in compressed format, and false otherwise.
+func IsCompressedPubKey(pubKey []byte) bool {
+	// The public key is only compressed if it is the correct length and
+	// the format (first byte) is one of the compressed pubkey values.
+	return len(pubKey) == PubKeyBytesLenCompressed &&
+		(pubKey[0]&^byte(0x1) == pubkeyCompressed)
+}
+
+// ParsePubKey parses a public key for a koblitz curve from a bytestring into a
+// ecdsa.Publickey, verifying that it is valid. It supports compressed,
+// uncompressed and hybrid signature formats.
+func ParsePubKey(pubKeyStr []byte) (*PublicKey, error) {
+	return secp256k1.ParsePubKey(pubKeyStr)
+}
+
+// PublicKey is an ecdsa.PublicKey with additional functions to
+// serialize in uncompressed, compressed, and hybrid formats.
+type PublicKey = secp256k1.PublicKey
+
+// NewPublicKey instantiates a new public key with the given x and y
+// coordinates.
+//
+// It should be noted that, unlike ParsePubKey, since this accepts arbitrary x
+// and y coordinates, it allows creation of public keys that are not valid
+// points on the secp256k1 curve.  The IsOnCurve method of the returned instance
+// can be used to determine validity.
+func NewPublicKey(x, y *FieldVal) *PublicKey {
+	return secp256k1.NewPublicKey(x, y)
+}