8923813580
Add jsdoc @module definitions. Fix references to old class names. Make keyring a multiple instance module. Eliminate unit test dependency on running npm test.
136 lines
4.8 KiB
JavaScript
136 lines
4.8 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
|
|
|
|
/** @module packet/sym_encrypted_session_key */
|
|
|
|
var type_s2k = require('../type/s2k.js'),
|
|
enums = require('../enums.js'),
|
|
crypto = require('../crypto');
|
|
|
|
/**
|
|
* @class
|
|
* @classdesc Public-Key Encrypted Session Key Packets (Tag 1)
|
|
*
|
|
* RFC4880 5.1: A Public-Key Encrypted Session Key packet holds the session key
|
|
* used to encrypt a message. Zero or more Public-Key Encrypted Session Key
|
|
* packets and/or Symmetric-Key Encrypted Session Key packets may precede a
|
|
* Symmetrically Encrypted Data Packet, which holds an encrypted message. The
|
|
* message is encrypted with the session key, and the session key is itself
|
|
* encrypted and stored in the Encrypted Session Key packet(s). The
|
|
* Symmetrically Encrypted Data Packet is preceded by one Public-Key Encrypted
|
|
* Session Key packet for each OpenPGP key to which the message is encrypted.
|
|
* The recipient of the message finds a session key that is encrypted to their
|
|
* public key, decrypts the session key, and then uses the session key to
|
|
* decrypt the message.
|
|
*/
|
|
module.exports = function packet_sym_encrypted_session_key() {
|
|
this.tag = 3;
|
|
this.sessionKeyEncryptionAlgorithm = null;
|
|
this.sessionKeyAlgorithm = 'aes256';
|
|
this.encrypted = null;
|
|
this.s2k = new type_s2k();
|
|
|
|
/**
|
|
* Parsing function for a symmetric encrypted session key packet (tag 3).
|
|
*
|
|
* @param {String} input Payload of a tag 1 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 {module:packet_encrypteddata} Object representation
|
|
*/
|
|
this.read = function(bytes) {
|
|
// A one-octet version number. The only currently defined version is 4.
|
|
this.version = bytes.charCodeAt(0);
|
|
|
|
// A one-octet number describing the symmetric algorithm used.
|
|
var algo = enums.read(enums.symmetric, bytes.charCodeAt(1));
|
|
|
|
// A string-to-key (S2K) specifier, length as defined above.
|
|
var s2klength = this.s2k.read(bytes.substr(2));
|
|
|
|
// Optionally, the encrypted session key itself, which is decrypted
|
|
// with the string-to-key object.
|
|
var done = s2klength + 2;
|
|
|
|
if (done < bytes.length) {
|
|
this.encrypted = bytes.substr(done);
|
|
this.sessionKeyEncryptionAlgorithm = algo
|
|
} else
|
|
this.sessionKeyAlgorithm = algo;
|
|
}
|
|
|
|
this.write = function() {
|
|
var algo = this.encrypted == null ?
|
|
this.sessionKeyAlgorithm :
|
|
this.sessionKeyEncryptionAlgorithm;
|
|
|
|
var bytes = String.fromCharCode(this.version) +
|
|
String.fromCharCode(enums.write(enums.symmetric, algo)) +
|
|
this.s2k.write();
|
|
|
|
if (this.encrypted != null)
|
|
bytes += this.encrypted;
|
|
return bytes;
|
|
}
|
|
|
|
/**
|
|
* Decrypts the session key (only for public key encrypted session key
|
|
* packets (tag 1)
|
|
*
|
|
* @return {String} The unencrypted session key
|
|
*/
|
|
this.decrypt = function(passphrase) {
|
|
var algo = this.sessionKeyEncryptionAlgorithm != null ?
|
|
this.sessionKeyEncryptionAlgorithm :
|
|
this.sessionKeyAlgorithm;
|
|
|
|
|
|
var length = crypto.cipher[algo].keySize;
|
|
var key = this.s2k.produce_key(passphrase, length);
|
|
|
|
if (this.encrypted == null) {
|
|
this.sessionKey = key;
|
|
|
|
} else {
|
|
var decrypted = crypto.cfb.decrypt(
|
|
this.sessionKeyEncryptionAlgorithm, key, this.encrypted, true);
|
|
|
|
this.sessionKeyAlgorithm = enums.read(enums.symmetric,
|
|
decrypted[0].keyCodeAt());
|
|
|
|
this.sessionKey = decrypted.substr(1);
|
|
}
|
|
}
|
|
|
|
this.encrypt = function(passphrase) {
|
|
var length = crypto.getKeyLength(this.sessionKeyEncryptionAlgorithm);
|
|
var key = this.s2k.produce_key(passphrase, length);
|
|
|
|
var private_key = String.fromCharCode(
|
|
enums.write(enums.symmetric, this.sessionKeyAlgorithm)) +
|
|
|
|
crypto.getRandomBytes(
|
|
crypto.getKeyLength(this.sessionKeyAlgorithm));
|
|
|
|
this.encrypted = crypto.cfb.encrypt(
|
|
crypto.getPrefixRandom(this.sessionKeyEncryptionAlgorithm),
|
|
this.sessionKeyEncryptionAlgorithm, key, private_key, true);
|
|
}
|
|
};
|