vendor/golang.org/x/crypto/openpgp/packet/one_pass_signature.go


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// 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 (
    "crypto"
    "encoding/binary"
    "golang.org/x/crypto/openpgp/errors"
    "golang.org/x/crypto/openpgp/s2k"
    "io"
    "strconv"
)

// OnePassSignature represents a one-pass signature packet. See RFC 4880,
// section 5.4.
type OnePassSignature struct {
    SigType    SignatureType
    Hash       crypto.Hash
    PubKeyAlgo PublicKeyAlgorithm
    KeyId      uint64
    IsLast     bool
}

const onePassSignatureVersion = 3

func (ops *OnePassSignature) parse(r io.Reader) (err error) {
    var buf [13]byte

    _, err = readFull(r, buf[:])
    if err != nil {
        return
    }
    if buf[0] != onePassSignatureVersion {
        err = errors.UnsupportedError("one-pass-signature packet version " + strconv.Itoa(int(buf[0])))
    }

    var ok bool
    ops.Hash, ok = s2k.HashIdToHash(buf[2])
    if !ok {
        return errors.UnsupportedError("hash function: " + strconv.Itoa(int(buf[2])))
    }

    ops.SigType = SignatureType(buf[1])
    ops.PubKeyAlgo = PublicKeyAlgorithm(buf[3])
    ops.KeyId = binary.BigEndian.Uint64(buf[4:12])
    ops.IsLast = buf[12] != 0
    return
}

// Serialize marshals the given OnePassSignature to w.
func (ops *OnePassSignature) Serialize(w io.Writer) error {
    var buf [13]byte
    buf[0] = onePassSignatureVersion
    buf[1] = uint8(ops.SigType)
    var ok bool
    buf[2], ok = s2k.HashToHashId(ops.Hash)
    if !ok {
        return errors.UnsupportedError("hash type: " + strconv.Itoa(int(ops.Hash)))
    }
    buf[3] = uint8(ops.PubKeyAlgo)
    binary.BigEndian.PutUint64(buf[4:12], ops.KeyId)
    if ops.IsLast {
        buf[12] = 1
    }

    if err := serializeHeader(w, packetTypeOnePassSignature, len(buf)); err != nil {
        return err
    }
    _, err := w.Write(buf[:])
    return err
}