89 lines
2.9 KiB
Go
89 lines
2.9 KiB
Go
// Copyright (c) 2013-2014 The btcsuite developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package btcec
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import (
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secp "github.com/decred/dcrd/dcrec/secp256k1/v4"
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)
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// These constants define the lengths of serialized public keys.
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const (
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// PubKeyBytesLenCompressed is the bytes length of a serialized compressed
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// public key.
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PubKeyBytesLenCompressed = 33
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)
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const (
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pubkeyCompressed byte = 0x2 // y_bit + x coord
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pubkeyUncompressed byte = 0x4 // x coord + y coord
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pubkeyHybrid byte = 0x6 // y_bit + x coord + y coord
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)
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// IsCompressedPubKey returns true the passed serialized public key has
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// been encoded in compressed format, and false otherwise.
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func IsCompressedPubKey(pubKey []byte) bool {
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// The public key is only compressed if it is the correct length and
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// the format (first byte) is one of the compressed pubkey values.
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return len(pubKey) == PubKeyBytesLenCompressed &&
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(pubKey[0]&^byte(0x1) == pubkeyCompressed)
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}
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// ParsePubKey parses a public key for a koblitz curve from a bytestring into a
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// ecdsa.Publickey, verifying that it is valid. It supports compressed,
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// uncompressed and hybrid signature formats.
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func ParsePubKey(pubKeyStr []byte) (*PublicKey, error) {
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return secp.ParsePubKey(pubKeyStr)
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}
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// PublicKey is an ecdsa.PublicKey with additional functions to
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// serialize in uncompressed, compressed, and hybrid formats.
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type PublicKey = secp.PublicKey
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// NewPublicKey instantiates a new public key with the given x and y
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// coordinates.
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//
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// It should be noted that, unlike ParsePubKey, since this accepts arbitrary x
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// and y coordinates, it allows creation of public keys that are not valid
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// points on the secp256k1 curve. The IsOnCurve method of the returned instance
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// can be used to determine validity.
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func NewPublicKey(x, y *FieldVal) *PublicKey {
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return secp.NewPublicKey(x, y)
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}
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// SerializedKey is a type for representing a public key in its compressed
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// serialized form.
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//
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// NOTE: This type is useful when using public keys as keys in maps.
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type SerializedKey [PubKeyBytesLenCompressed]byte
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// ToPubKey returns the public key parsed from the serialized key.
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func (s SerializedKey) ToPubKey() (*PublicKey, error) {
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return ParsePubKey(s[:])
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}
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// SchnorrSerialized returns the Schnorr serialized, x-only 32-byte
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// representation of the serialized key.
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func (s SerializedKey) SchnorrSerialized() [32]byte {
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var serializedSchnorr [32]byte
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copy(serializedSchnorr[:], s[1:])
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return serializedSchnorr
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}
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// CopyBytes returns a copy of the underlying array as a byte slice.
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func (s SerializedKey) CopyBytes() []byte {
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c := make([]byte, PubKeyBytesLenCompressed)
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copy(c, s[:])
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return c
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}
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// ToSerialized serializes a public key into its compressed form.
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func ToSerialized(pubKey *PublicKey) SerializedKey {
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var serialized SerializedKey
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copy(serialized[:], pubKey.SerializeCompressed())
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return serialized
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}
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