fork-openpgpjs/src/packet/openpgp.packet.onepasssignature.js
2013-01-04 11:58:51 -05:00

120 lines
5.3 KiB
JavaScript

// GPG4Browsers - An OpenPGP implementation in javascript
// Copyright (C) 2011 Recurity Labs GmbH
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
/**
* @class
* @classdesc Implementation of the One-Pass Signature Packets (Tag 4)
*
* RFC4880 5.4:
* The One-Pass Signature packet precedes the signed data and contains
* enough information to allow the receiver to begin calculating any
* hashes needed to verify the signature. It allows the Signature
* packet to be placed at the end of the message, so that the signer
* can compute the entire signed message in one pass.
*/
function openpgp_packet_onepasssignature() {
this.tagType = 4;
this.version = null; // A one-octet version number. The current version is 3.
this.type = null; // A one-octet signature type. Signature types are described in RFC4880 Section 5.2.1.
this.hashAlgorithm = null; // A one-octet number describing the hash algorithm used. (See RFC4880 9.4)
this.publicKeyAlgorithm = null; // A one-octet number describing the public-key algorithm used. (See RFC4880 9.1)
this.signingKeyId = null; // An eight-octet number holding the Key ID of the signing key.
this.flags = null; // A one-octet number holding a flag showing whether the signature is nested. A zero value indicates that the next packet is another One-Pass Signature packet that describes another signature to be applied to the same message data.
/**
* parsing function for a one-pass signature packet (tag 4).
* @param {string} input payload of a tag 4 packet
* @param {integer} position position to start reading from the input string
* @param {integer} len length of the packet or the remaining length of input at position
* @return {openpgp_packet_encrypteddata} object representation
*/
function read_packet(input, position, len) {
this.packetLength = len;
var mypos = position;
// A one-octet version number. The current version is 3.
this.version = input.charCodeAt(mypos++);
// A one-octet signature type. Signature types are described in
// Section 5.2.1.
this.type = input.charCodeAt(mypos++);
// A one-octet number describing the hash algorithm used.
this.hashAlgorithm = input.charCodeAt(mypos++);
// A one-octet number describing the public-key algorithm used.
this.publicKeyAlgorithm = input.charCodeAt(mypos++);
// An eight-octet number holding the Key ID of the signing key.
this.signingKeyId = new openpgp_type_keyid();
this.signingKeyId.read_packet(input,mypos);
mypos += 8;
// A one-octet number holding a flag showing whether the signature
// is nested. A zero value indicates that the next packet is
// another One-Pass Signature packet that describes another
// signature to be applied to the same message data.
this.flags = input.charCodeAt(mypos++);
return this;
}
/**
* creates a string representation of a one-pass signature packet
* @param {integer} type Signature types as described in RFC4880 Section 5.2.1.
* @param {integer} hashalgorithm the hash algorithm used within the signature
* @param {openpgp_msg_privatekey} privatekey the private key used to generate the signature
* @param {integer} length length of data to be signed
* @param {boolean} nested boolean showing whether the signature is nested.
* "true" indicates that the next packet is another One-Pass Signature packet
* that describes another signature to be applied to the same message data.
* @return {String} a string representation of a one-pass signature packet
*/
function write_packet(type, hashalgorithm, privatekey,length, nested) {
var result ="";
result += openpgp_packet.write_packet_header(4,13);
result += String.fromCharCode(3);
result += String.fromCharCode(type);
result += String.fromCharCode(hashalgorithm);
result += String.fromCharCode(privatekey.privateKeyPacket.publicKey.publicKeyAlgorithm);
result += privatekey.getKeyId();
if (nested)
result += String.fromCharCode(0);
else
result += String.fromCharCode(1);
return result;
}
/**
* generates debug output (pretty print)
* @return {string} String which gives some information about the one-pass signature packet
*/
function toString() {
return '5.4. One-Pass Signature Packets (Tag 4)\n'+
' length: '+this.packetLength+'\n'+
' type: '+this.type+'\n'+
' keyID: '+this.signingKeyId.toString()+'\n'+
' hashA: '+this.hashAlgorithm+'\n'+
' pubKeyA:'+this.publicKeyAlgorithm+'\n'+
' flags: '+this.flags+'\n'+
' version:'+this.version+'\n';
}
this.read_packet = read_packet;
this.toString = toString;
this.write_packet = write_packet;
};