one_pass_signature.go

Documentation: golang.org/x/crypto/openpgp/packet

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package packet
     6  
     7  import (
     8  	"crypto"
     9  	"encoding/binary"
    10  	"golang.org/x/crypto/openpgp/errors"
    11  	"golang.org/x/crypto/openpgp/s2k"
    12  	"io"
    13  	"strconv"
    14  )
    15  
    16  // OnePassSignature represents a one-pass signature packet. See RFC 4880,
    17  // section 5.4.
    18  type OnePassSignature struct {
    19  	SigType    SignatureType
    20  	Hash       crypto.Hash
    21  	PubKeyAlgo PublicKeyAlgorithm
    22  	KeyId      uint64
    23  	IsLast     bool
    24  }
    25  
    26  const onePassSignatureVersion = 3
    27  
    28  func (ops *OnePassSignature) parse(r io.Reader) (err error) {
    29  	var buf [13]byte
    30  
    31  	_, err = readFull(r, buf[:])
    32  	if err != nil {
    33  		return
    34  	}
    35  	if buf[0] != onePassSignatureVersion {
    36  		err = errors.UnsupportedError("one-pass-signature packet version " + strconv.Itoa(int(buf[0])))
    37  	}
    38  
    39  	var ok bool
    40  	ops.Hash, ok = s2k.HashIdToHash(buf[2])
    41  	if !ok {
    42  		return errors.UnsupportedError("hash function: " + strconv.Itoa(int(buf[2])))
    43  	}
    44  
    45  	ops.SigType = SignatureType(buf[1])
    46  	ops.PubKeyAlgo = PublicKeyAlgorithm(buf[3])
    47  	ops.KeyId = binary.BigEndian.Uint64(buf[4:12])
    48  	ops.IsLast = buf[12] != 0
    49  	return
    50  }
    51  
    52  // Serialize marshals the given OnePassSignature to w.
    53  func (ops *OnePassSignature) Serialize(w io.Writer) error {
    54  	var buf [13]byte
    55  	buf[0] = onePassSignatureVersion
    56  	buf[1] = uint8(ops.SigType)
    57  	var ok bool
    58  	buf[2], ok = s2k.HashToHashId(ops.Hash)
    59  	if !ok {
    60  		return errors.UnsupportedError("hash type: " + strconv.Itoa(int(ops.Hash)))
    61  	}
    62  	buf[3] = uint8(ops.PubKeyAlgo)
    63  	binary.BigEndian.PutUint64(buf[4:12], ops.KeyId)
    64  	if ops.IsLast {
    65  		buf[12] = 1
    66  	}
    67  
    68  	if err := serializeHeader(w, packetTypeOnePassSignature, len(buf)); err != nil {
    69  		return err
    70  	}
    71  	_, err := w.Write(buf[:])
    72  	return err
    73  }
    74
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