96 lines
4.1 KiB
JavaScript
96 lines
4.1 KiB
JavaScript
// GPG4Browsers - An OpenPGP implementation in javascript
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// Copyright (C) 2011 Recurity Labs GmbH
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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/**
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* Implementation of the One-Pass Signature Packets (Tag 4)<br/>
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* <br/>
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* RFC4880 5.4:
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* The One-Pass Signature packet precedes the signed data and contains
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* enough information to allow the receiver to begin calculating any
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* hashes needed to verify the signature. It allows the Signature
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* packet to be placed at the end of the message, so that the signer
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* can compute the entire signed message in one pass.
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* @requires enums
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* @requires type/keyid
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* @module packet/one_pass_signature
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*/
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var enums = require('../enums.js'),
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type_keyid = require('../type/keyid.js');
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/**
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* @constructor
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*/
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module.exports = function one_pass_signature() {
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this.version = null; // A one-octet version number. The current version is 3.
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this.type = null; // A one-octet signature type. Signature types are described in RFC4880 Section 5.2.1.
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this.hashAlgorithm = null; // A one-octet number describing the hash algorithm used. (See RFC4880 9.4)
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this.publicKeyAlgorithm = null; // A one-octet number describing the public-key algorithm used. (See RFC4880 9.1)
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this.signingKeyId = null; // An eight-octet number holding the Key ID of the signing key.
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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.
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/**
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* parsing function for a one-pass signature packet (tag 4).
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* @param {String} bytes payload of a tag 4 packet
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* @return {module:packet/one_pass_signature} object representation
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*/
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this.read = function (bytes) {
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var mypos = 0;
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// A one-octet version number. The current version is 3.
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this.version = bytes.charCodeAt(mypos++);
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// A one-octet signature type. Signature types are described in
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// Section 5.2.1.
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this.type = enums.read(enums.signature, bytes.charCodeAt(mypos++));
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// A one-octet number describing the hash algorithm used.
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this.hashAlgorithm = enums.read(enums.hash, bytes.charCodeAt(mypos++));
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// A one-octet number describing the public-key algorithm used.
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this.publicKeyAlgorithm = enums.read(enums.publicKey, bytes.charCodeAt(mypos++));
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// An eight-octet number holding the Key ID of the signing key.
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this.signingKeyId = new type_keyid();
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this.signingKeyId.read(bytes.substr(mypos));
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mypos += 8;
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// A one-octet number holding a flag showing whether the signature
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// is nested. A zero value indicates that the next packet is
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// another One-Pass Signature packet that describes another
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// signature to be applied to the same message data.
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this.flags = bytes.charCodeAt(mypos++);
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return this;
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};
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/**
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* creates a string representation of a one-pass signature packet
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* @return {String} a string representation of a one-pass signature packet
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*/
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this.write = function () {
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var result = "";
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result += String.fromCharCode(3);
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result += String.fromCharCode(enums.write(enums.signature, this.type));
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result += String.fromCharCode(enums.write(enums.hash, this.hashAlgorithm));
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result += String.fromCharCode(enums.write(enums.publicKey, this.publicKeyAlgorithm));
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result += this.signingKeyId.write();
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result += String.fromCharCode(this.flags);
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return result;
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};
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};
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