// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package packet
import (
"bytes"
"crypto"
"crypto/dsa"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rsa"
"crypto/sha1"
_ "crypto/sha256"
_ "crypto/sha512"
"encoding/binary"
"fmt"
"hash"
"io"
"math/big"
"strconv"
"time"
"golang.org/x/crypto/openpgp/elgamal"
"golang.org/x/crypto/openpgp/errors"
)
var (
// NIST curve P-256
oidCurveP256 []byte = []byte{0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x03, 0x01, 0x07}
// NIST curve P-384
oidCurveP384 []byte = []byte{0x2B, 0x81, 0x04, 0x00, 0x22}
// NIST curve P-521
oidCurveP521 []byte = []byte{0x2B, 0x81, 0x04, 0x00, 0x23}
)
const maxOIDLength = 8
// ecdsaKey stores the algorithm-specific fields for ECDSA keys.
// as defined in RFC 6637, Section 9.
type ecdsaKey struct {
// oid contains the OID byte sequence identifying the elliptic curve used
oid []byte
// p contains the elliptic curve point that represents the public key
p parsedMPI
}
// parseOID reads the OID for the curve as defined in RFC 6637, Section 9.
func parseOID(r io.Reader) (oid []byte, err error) {
buf := make([]byte, maxOIDLength)
if _, err = readFull(r, buf[:1]); err != nil {
return
}
oidLen := buf[0]
if int(oidLen) > len(buf) {
err = errors.UnsupportedError("invalid oid length: " + strconv.Itoa(int(oidLen)))
return
}
oid = buf[:oidLen]
_, err = readFull(r, oid)
return
}
func (f *ecdsaKey) parse(r io.Reader) (err error) {
if f.oid, err = parseOID(r); err != nil {
return err
}
f.p.bytes, f.p.bitLength, err = readMPI(r)
return
}
func (f *ecdsaKey) serialize(w io.Writer) (err error) {
buf := make([]byte, maxOIDLength+1)
buf[0] = byte(len(f.oid))
copy(buf[1:], f.oid)
if _, err = w.Write(buf[:len(f.oid)+1]); err != nil {
return
}
return writeMPIs(w, f.p)
}
func (f *ecdsaKey) newECDSA() (*ecdsa.PublicKey, error) {
var c elliptic.Curve
if bytes.Equal(f.oid, oidCurveP256) {
c = elliptic.P256()
} else if bytes.Equal(f.oid, oidCurveP384) {
c = elliptic.P384()
} else if bytes.Equal(f.oid, oidCurveP521) {
c = elliptic.P521()
} else {
return nil, errors.UnsupportedError(fmt.Sprintf("unsupported oid: %x", f.oid))
}
x, y := elliptic.Unmarshal(c, f.p.bytes)
if x == nil {
return nil, errors.UnsupportedError("failed to parse EC point")
}
return &ecdsa.PublicKey{Curve: c, X: x, Y: y}, nil
}
func (f *ecdsaKey) byteLen() int {
return 1 + len(f.oid) + 2 + len(f.p.bytes)
}
type kdfHashFunction byte
type kdfAlgorithm byte
// ecdhKdf stores key derivation function parameters
// used for ECDH encryption. See RFC 6637, Section 9.
type ecdhKdf struct {
KdfHash kdfHashFunction
KdfAlgo kdfAlgorithm
}
func (f *ecdhKdf) parse(r io.Reader) (err error) {
buf := make([]byte, 1)
if _, err = readFull(r, buf); err != nil {
return
}
kdfLen := int(buf[0])
if kdfLen < 3 {
return errors.UnsupportedError("Unsupported ECDH KDF length: " + strconv.Itoa(kdfLen))
}
buf = make([]byte, kdfLen)
if _, err = readFull(r, buf); err != nil {
return
}
reserved := int(buf[0])
f.KdfHash = kdfHashFunction(buf[1])
f.KdfAlgo = kdfAlgorithm(buf[2])
if reserved != 0x01 {
return errors.UnsupportedError("Unsupported KDF reserved field: " + strconv.Itoa(reserved))
}
return
}
func (f *ecdhKdf) serialize(w io.Writer) (err error) {
buf := make([]byte, 4)
// See RFC 6637, Section 9, Algorithm-Specific Fields for ECDH keys.
buf[0] = byte(0x03) // Length of the following fields
buf[1] = byte(0x01) // Reserved for future extensions, must be 1 for now
buf[2] = byte(f.KdfHash)
buf[3] = byte(f.KdfAlgo)
_, err = w.Write(buf[:])
return
}
func (f *ecdhKdf) byteLen() int {
return 4
}
// PublicKey represents an OpenPGP public key. See RFC 4880, section 5.5.2.
type PublicKey struct {
CreationTime time.Time
PubKeyAlgo PublicKeyAlgorithm
PublicKey interface{} // *rsa.PublicKey, *dsa.PublicKey or *ecdsa.PublicKey
Fingerprint [20]byte
KeyId uint64
IsSubkey bool
n, e, p, q, g, y parsedMPI
// RFC 6637 fields
ec *ecdsaKey
ecdh *ecdhKdf
}
// signingKey provides a convenient abstraction over signature verification
// for v3 and v4 public keys.
type signingKey interface {
SerializeSignaturePrefix(io.Writer)
serializeWithoutHeaders(io.Writer) error
}
func fromBig(n *big.Int) parsedMPI {
return parsedMPI{
bytes: n.Bytes(),
bitLength: uint16(n.BitLen()),
}
}
// NewRSAPublicKey returns a PublicKey that wraps the given rsa.PublicKey.
func NewRSAPublicKey(creationTime time.Time, pub *rsa.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoRSA,
PublicKey: pub,
n: fromBig(pub.N),
e: fromBig(big.NewInt(int64(pub.E))),
}
pk.setFingerPrintAndKeyId()
return pk
}
// NewDSAPublicKey returns a PublicKey that wraps the given dsa.PublicKey.
func NewDSAPublicKey(creationTime time.Time, pub *dsa.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoDSA,
PublicKey: pub,
p: fromBig(pub.P),
q: fromBig(pub.Q),
g: fromBig(pub.G),
y: fromBig(pub.Y),
}
pk.setFingerPrintAndKeyId()
return pk
}
// NewElGamalPublicKey returns a PublicKey that wraps the given elgamal.PublicKey.
func NewElGamalPublicKey(creationTime time.Time, pub *elgamal.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoElGamal,
PublicKey: pub,
p: fromBig(pub.P),
g: fromBig(pub.G),
y: fromBig(pub.Y),
}
pk.setFingerPrintAndKeyId()
return pk
}
func NewECDSAPublicKey(creationTime time.Time, pub *ecdsa.PublicKey) *PublicKey {
pk := &PublicKey{
CreationTime: creationTime,
PubKeyAlgo: PubKeyAlgoECDSA,
PublicKey: pub,
ec: new(ecdsaKey),
}
switch pub.Curve {
case elliptic.P256():
pk.ec.oid = oidCurveP256
case elliptic.P384():
pk.ec.oid = oidCurveP384
case elliptic.P521():
pk.ec.oid = oidCurveP521
default:
panic("unknown elliptic curve")
}
pk.ec.p.bytes = elliptic.Marshal(pub.Curve, pub.X, pub.Y)
// The bit length is 3 (for the 0x04 specifying an uncompressed key)
// plus two field elements (for x and y), which are rounded up to the
// nearest byte. See https://tools.ietf.org/html/rfc6637#section-6
fieldBytes := (pub.Curve.Params().BitSize + 7) & ^7
pk.ec.p.bitLength = uint16(3 + fieldBytes + fieldBytes)
pk.setFingerPrintAndKeyId()
return pk
}
func (pk *PublicKey) parse(r io.Reader) (err error) {
// RFC 4880, section 5.5.2
var buf [6]byte
_, err = readFull(r, buf[:])
if err != nil {
return
}
if buf[0] != 4 {
return errors.UnsupportedError("public key version")
}
pk.CreationTime = time.Unix(int64(uint32(buf[1])<<24|uint32(buf[2])<<16|uint32(buf[3])<<8|uint32(buf[4])), 0)
pk.PubKeyAlgo = PublicKeyAlgorithm(buf[5])
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
err = pk.parseRSA(r)
case PubKeyAlgoDSA:
err = pk.parseDSA(r)
case PubKeyAlgoElGamal:
err = pk.parseElGamal(r)
case PubKeyAlgoECDSA:
pk.ec = new(ecdsaKey)
if err = pk.ec.parse(r); err != nil {
return err
}
pk.PublicKey, err = pk.ec.newECDSA()
case PubKeyAlgoECDH:
pk.ec = new(ecdsaKey)
if err = pk.ec.parse(r); err != nil {
return
}
pk.ecdh = new(ecdhKdf)
if err = pk.ecdh.parse(r); err != nil {
return
}
// The ECDH key is stored in an ecdsa.PublicKey for convenience.
pk.PublicKey, err = pk.ec.newECDSA()
default:
err = errors.UnsupportedError("public key type: " + strconv.Itoa(int(pk.PubKeyAlgo)))
}
if err != nil {
return
}
pk.setFingerPrintAndKeyId()
return
}
func (pk *PublicKey) setFingerPrintAndKeyId() {
// RFC 4880, section 12.2
fingerPrint := sha1.New()
pk.SerializeSignaturePrefix(fingerPrint)
pk.serializeWithoutHeaders(fingerPrint)
copy(pk.Fingerprint[:], fingerPrint.Sum(nil))
pk.KeyId = binary.BigEndian.Uint64(pk.Fingerprint[12:20])
}
// parseRSA parses RSA public key material from the given Reader. See RFC 4880,
// section 5.5.2.
func (pk *PublicKey) parseRSA(r io.Reader) (err error) {
pk.n.bytes, pk.n.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.e.bytes, pk.e.bitLength, err = readMPI(r)
if err != nil {
return
}
if len(pk.e.bytes) > 3 {
err = errors.UnsupportedError("large public exponent")
return
}
rsa := &rsa.PublicKey{
N: new(big.Int).SetBytes(pk.n.bytes),
E: 0,
}
for i := 0; i < len(pk.e.bytes); i++ {
rsa.E <<= 8
rsa.E |= int(pk.e.bytes[i])
}
pk.PublicKey = rsa
return
}
// parseDSA parses DSA public key material from the given Reader. See RFC 4880,
// section 5.5.2.
func (pk *PublicKey) parseDSA(r io.Reader) (err error) {
pk.p.bytes, pk.p.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.q.bytes, pk.q.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.g.bytes, pk.g.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.y.bytes, pk.y.bitLength, err = readMPI(r)
if err != nil {
return
}
dsa := new(dsa.PublicKey)
dsa.P = new(big.Int).SetBytes(pk.p.bytes)
dsa.Q = new(big.Int).SetBytes(pk.q.bytes)
dsa.G = new(big.Int).SetBytes(pk.g.bytes)
dsa.Y = new(big.Int).SetBytes(pk.y.bytes)
pk.PublicKey = dsa
return
}
// parseElGamal parses ElGamal public key material from the given Reader. See
// RFC 4880, section 5.5.2.
func (pk *PublicKey) parseElGamal(r io.Reader) (err error) {
pk.p.bytes, pk.p.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.g.bytes, pk.g.bitLength, err = readMPI(r)
if err != nil {
return
}
pk.y.bytes, pk.y.bitLength, err = readMPI(r)
if err != nil {
return
}
elgamal := new(elgamal.PublicKey)
elgamal.P = new(big.Int).SetBytes(pk.p.bytes)
elgamal.G = new(big.Int).SetBytes(pk.g.bytes)
elgamal.Y = new(big.Int).SetBytes(pk.y.bytes)
pk.PublicKey = elgamal
return
}
// SerializeSignaturePrefix writes the prefix for this public key to the given Writer.
// The prefix is used when calculating a signature over this public key. See
// RFC 4880, section 5.2.4.
func (pk *PublicKey) SerializeSignaturePrefix(h io.Writer) {
var pLength uint16
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
pLength += 2 + uint16(len(pk.n.bytes))
pLength += 2 + uint16(len(pk.e.bytes))
case PubKeyAlgoDSA:
pLength += 2 + uint16(len(pk.p.bytes))
pLength += 2 + uint16(len(pk.q.bytes))
pLength += 2 + uint16(len(pk.g.bytes))
pLength += 2 + uint16(len(pk.y.bytes))
case PubKeyAlgoElGamal:
pLength += 2 + uint16(len(pk.p.bytes))
pLength += 2 + uint16(len(pk.g.bytes))
pLength += 2 + uint16(len(pk.y.bytes))
case PubKeyAlgoECDSA:
pLength += uint16(pk.ec.byteLen())
case PubKeyAlgoECDH:
pLength += uint16(pk.ec.byteLen())
pLength += uint16(pk.ecdh.byteLen())
default:
panic("unknown public key algorithm")
}
pLength += 6
h.Write([]byte{0x99, byte(pLength >> 8), byte(pLength)})
return
}
func (pk *PublicKey) Serialize(w io.Writer) (err error) {
length := 6 // 6 byte header
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
length += 2 + len(pk.n.bytes)
length += 2 + len(pk.e.bytes)
case PubKeyAlgoDSA:
length += 2 + len(pk.p.bytes)
length += 2 + len(pk.q.bytes)
length += 2 + len(pk.g.bytes)
length += 2 + len(pk.y.bytes)
case PubKeyAlgoElGamal:
length += 2 + len(pk.p.bytes)
length += 2 + len(pk.g.bytes)
length += 2 + len(pk.y.bytes)
case PubKeyAlgoECDSA:
length += pk.ec.byteLen()
case PubKeyAlgoECDH:
length += pk.ec.byteLen()
length += pk.ecdh.byteLen()
default:
panic("unknown public key algorithm")
}
packetType := packetTypePublicKey
if pk.IsSubkey {
packetType = packetTypePublicSubkey
}
err = serializeHeader(w, packetType, length)
if err != nil {
return
}
return pk.serializeWithoutHeaders(w)
}
// serializeWithoutHeaders marshals the PublicKey to w in the form of an
// OpenPGP public key packet, not including the packet header.
func (pk *PublicKey) serializeWithoutHeaders(w io.Writer) (err error) {
var buf [6]byte
buf[0] = 4
t := uint32(pk.CreationTime.Unix())
buf[1] = byte(t >> 24)
buf[2] = byte(t >> 16)
buf[3] = byte(t >> 8)
buf[4] = byte(t)
buf[5] = byte(pk.PubKeyAlgo)
_, err = w.Write(buf[:])
if err != nil {
return
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
return writeMPIs(w, pk.n, pk.e)
case PubKeyAlgoDSA:
return writeMPIs(w, pk.p, pk.q, pk.g, pk.y)
case PubKeyAlgoElGamal:
return writeMPIs(w, pk.p, pk.g, pk.y)
case PubKeyAlgoECDSA:
return pk.ec.serialize(w)
case PubKeyAlgoECDH:
if err = pk.ec.serialize(w); err != nil {
return
}
return pk.ecdh.serialize(w)
}
return errors.InvalidArgumentError("bad public-key algorithm")
}
// CanSign returns true iff this public key can generate signatures
func (pk *PublicKey) CanSign() bool {
return pk.PubKeyAlgo != PubKeyAlgoRSAEncryptOnly && pk.PubKeyAlgo != PubKeyAlgoElGamal
}
// VerifySignature returns nil iff sig is a valid signature, made by this
// public key, of the data hashed into signed. signed is mutated by this call.
func (pk *PublicKey) VerifySignature(signed hash.Hash, sig *Signature) (err error) {
if !pk.CanSign() {
return errors.InvalidArgumentError("public key cannot generate signatures")
}
signed.Write(sig.HashSuffix)
hashBytes := signed.Sum(nil)
if hashBytes[0] != sig.HashTag[0] || hashBytes[1] != sig.HashTag[1] {
return errors.SignatureError("hash tag doesn't match")
}
if pk.PubKeyAlgo != sig.PubKeyAlgo {
return errors.InvalidArgumentError("public key and signature use different algorithms")
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
rsaPublicKey, _ := pk.PublicKey.(*rsa.PublicKey)
err = rsa.VerifyPKCS1v15(rsaPublicKey, sig.Hash, hashBytes, padToKeySize(rsaPublicKey, sig.RSASignature.bytes))
if err != nil {
return errors.SignatureError("RSA verification failure")
}
return nil
case PubKeyAlgoDSA:
dsaPublicKey, _ := pk.PublicKey.(*dsa.PublicKey)
// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
subgroupSize := (dsaPublicKey.Q.BitLen() + 7) / 8
if len(hashBytes) > subgroupSize {
hashBytes = hashBytes[:subgroupSize]
}
if !dsa.Verify(dsaPublicKey, hashBytes, new(big.Int).SetBytes(sig.DSASigR.bytes), new(big.Int).SetBytes(sig.DSASigS.bytes)) {
return errors.SignatureError("DSA verification failure")
}
return nil
case PubKeyAlgoECDSA:
ecdsaPublicKey := pk.PublicKey.(*ecdsa.PublicKey)
if !ecdsa.Verify(ecdsaPublicKey, hashBytes, new(big.Int).SetBytes(sig.ECDSASigR.bytes), new(big.Int).SetBytes(sig.ECDSASigS.bytes)) {
return errors.SignatureError("ECDSA verification failure")
}
return nil
default:
return errors.SignatureError("Unsupported public key algorithm used in signature")
}
}
// VerifySignatureV3 returns nil iff sig is a valid signature, made by this
// public key, of the data hashed into signed. signed is mutated by this call.
func (pk *PublicKey) VerifySignatureV3(signed hash.Hash, sig *SignatureV3) (err error) {
if !pk.CanSign() {
return errors.InvalidArgumentError("public key cannot generate signatures")
}
suffix := make([]byte, 5)
suffix[0] = byte(sig.SigType)
binary.BigEndian.PutUint32(suffix[1:], uint32(sig.CreationTime.Unix()))
signed.Write(suffix)
hashBytes := signed.Sum(nil)
if hashBytes[0] != sig.HashTag[0] || hashBytes[1] != sig.HashTag[1] {
return errors.SignatureError("hash tag doesn't match")
}
if pk.PubKeyAlgo != sig.PubKeyAlgo {
return errors.InvalidArgumentError("public key and signature use different algorithms")
}
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
rsaPublicKey := pk.PublicKey.(*rsa.PublicKey)
if err = rsa.VerifyPKCS1v15(rsaPublicKey, sig.Hash, hashBytes, padToKeySize(rsaPublicKey, sig.RSASignature.bytes)); err != nil {
return errors.SignatureError("RSA verification failure")
}
return
case PubKeyAlgoDSA:
dsaPublicKey := pk.PublicKey.(*dsa.PublicKey)
// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
subgroupSize := (dsaPublicKey.Q.BitLen() + 7) / 8
if len(hashBytes) > subgroupSize {
hashBytes = hashBytes[:subgroupSize]
}
if !dsa.Verify(dsaPublicKey, hashBytes, new(big.Int).SetBytes(sig.DSASigR.bytes), new(big.Int).SetBytes(sig.DSASigS.bytes)) {
return errors.SignatureError("DSA verification failure")
}
return nil
default:
panic("shouldn't happen")
}
}
// keySignatureHash returns a Hash of the message that needs to be signed for
// pk to assert a subkey relationship to signed.
func keySignatureHash(pk, signed signingKey, hashFunc crypto.Hash) (h hash.Hash, err error) {
if !hashFunc.Available() {
return nil, errors.UnsupportedError("hash function")
}
h = hashFunc.New()
// RFC 4880, section 5.2.4
pk.SerializeSignaturePrefix(h)
pk.serializeWithoutHeaders(h)
signed.SerializeSignaturePrefix(h)
signed.serializeWithoutHeaders(h)
return
}
// VerifyKeySignature returns nil iff sig is a valid signature, made by this
// public key, of signed.
func (pk *PublicKey) VerifyKeySignature(signed *PublicKey, sig *Signature) error {
h, err := keySignatureHash(pk, signed, sig.Hash)
if err != nil {
return err
}
if err = pk.VerifySignature(h, sig); err != nil {
return err
}
if sig.FlagSign {
// Signing subkeys must be cross-signed. See
// https://www.gnupg.org/faq/subkey-cross-certify.html.
if sig.EmbeddedSignature == nil {
return errors.StructuralError("signing subkey is missing cross-signature")
}
// Verify the cross-signature. This is calculated over the same
// data as the main signature, so we cannot just recursively
// call signed.VerifyKeySignature(...)
if h, err = keySignatureHash(pk, signed, sig.EmbeddedSignature.Hash); err != nil {
return errors.StructuralError("error while hashing for cross-signature: " + err.Error())
}
if err := signed.VerifySignature(h, sig.EmbeddedSignature); err != nil {
return errors.StructuralError("error while verifying cross-signature: " + err.Error())
}
}
return nil
}
func keyRevocationHash(pk signingKey, hashFunc crypto.Hash) (h hash.Hash, err error) {
if !hashFunc.Available() {
return nil, errors.UnsupportedError("hash function")
}
h = hashFunc.New()
// RFC 4880, section 5.2.4
pk.SerializeSignaturePrefix(h)
pk.serializeWithoutHeaders(h)
return
}
// VerifyRevocationSignature returns nil iff sig is a valid signature, made by this
// public key.
func (pk *PublicKey) VerifyRevocationSignature(sig *Signature) (err error) {
h, err := keyRevocationHash(pk, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignature(h, sig)
}
// userIdSignatureHash returns a Hash of the message that needs to be signed
// to assert that pk is a valid key for id.
func userIdSignatureHash(id string, pk *PublicKey, hashFunc crypto.Hash) (h hash.Hash, err error) {
if !hashFunc.Available() {
return nil, errors.UnsupportedError("hash function")
}
h = hashFunc.New()
// RFC 4880, section 5.2.4
pk.SerializeSignaturePrefix(h)
pk.serializeWithoutHeaders(h)
var buf [5]byte
buf[0] = 0xb4
buf[1] = byte(len(id) >> 24)
buf[2] = byte(len(id) >> 16)
buf[3] = byte(len(id) >> 8)
buf[4] = byte(len(id))
h.Write(buf[:])
h.Write([]byte(id))
return
}
// VerifyUserIdSignature returns nil iff sig is a valid signature, made by this
// public key, that id is the identity of pub.
func (pk *PublicKey) VerifyUserIdSignature(id string, pub *PublicKey, sig *Signature) (err error) {
h, err := userIdSignatureHash(id, pub, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignature(h, sig)
}
// VerifyUserIdSignatureV3 returns nil iff sig is a valid signature, made by this
// public key, that id is the identity of pub.
func (pk *PublicKey) VerifyUserIdSignatureV3(id string, pub *PublicKey, sig *SignatureV3) (err error) {
h, err := userIdSignatureV3Hash(id, pub, sig.Hash)
if err != nil {
return err
}
return pk.VerifySignatureV3(h, sig)
}
// KeyIdString returns the public key's fingerprint in capital hex
// (e.g. "6C7EE1B8621CC013").
func (pk *PublicKey) KeyIdString() string {
return fmt.Sprintf("%X", pk.Fingerprint[12:20])
}
// KeyIdShortString returns the short form of public key's fingerprint
// in capital hex, as shown by gpg --list-keys (e.g. "621CC013").
func (pk *PublicKey) KeyIdShortString() string {
return fmt.Sprintf("%X", pk.Fingerprint[16:20])
}
// A parsedMPI is used to store the contents of a big integer, along with the
// bit length that was specified in the original input. This allows the MPI to
// be reserialized exactly.
type parsedMPI struct {
bytes []byte
bitLength uint16
}
// writeMPIs is a utility function for serializing several big integers to the
// given Writer.
func writeMPIs(w io.Writer, mpis ...parsedMPI) (err error) {
for _, mpi := range mpis {
err = writeMPI(w, mpi.bitLength, mpi.bytes)
if err != nil {
return
}
}
return
}
// BitLength returns the bit length for the given public key.
func (pk *PublicKey) BitLength() (bitLength uint16, err error) {
switch pk.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
bitLength = pk.n.bitLength
case PubKeyAlgoDSA:
bitLength = pk.p.bitLength
case PubKeyAlgoElGamal:
bitLength = pk.p.bitLength
default:
err = errors.InvalidArgumentError("bad public-key algorithm")
}
return
}
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