Merge pull request #118 from toberndo/devel

devel branch: First draft of encrypt message function

src/key.js

@@ -15,6 +15,10 @@
 // License along with this library; if not, write to the Free Software
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 
+var packet = require('./packet');
+var enums = require('./enums.js');
+
+
 /**
  * @class
  * @classdesc Class that represents an OpenPGP key. Must contain a master key. 
@@ -22,15 +26,16 @@
  * user ids, user attributes.
  */
 
-function openpgp_key() {
-  this.packets = new openpgp_packetlist();
+module.exports = function key() {
 
-  /** Returns the master key (secret or public)
+  this.packets = new packet.list();
+
+  /** Returns the primary key (secret or public)
    * @returns {openpgp_packet_secret_key|openpgp_packet_public_key|null} */
   this.getKey = function() {
     for (var i = 0; i < this.packets.length; i++)
-      if (this.packets[i].tag == openpgp_packets.tags.public_key ||
-        this.packets[i].tag == openpgp_packets.tags.secret_key)
+      if (this.packets[i].tag == enums.packet.public_key ||
+        this.packets[i].tag == enums.packet.secret_key)
         return this.packets[i];
 
     return null;
@@ -43,8 +48,8 @@ function openpgp_key() {
     var subkeys = [];
 
     for (var i = 0; i < this.packets.length; i++)
-      if (this.packets[i].tag == openpgp_packet.tags.public_subkey ||
-        this.packets[i].tag == openpgp_packet.tags.secret_subkey)
+      if (this.packets[i].tag == enums.packet.public_subkey ||
+        this.packets[i].tag == enums.packet.secret_subkey)
         subkeys.push(this.packets[i]);
 
     return subkeys;
@@ -84,15 +89,44 @@ function openpgp_key() {
     //TODO implement: https://tools.ietf.org/html/rfc4880#section-5.2.3.8
     //separate private key preference from digest preferences
     return openpgp.config.config.prefer_hash_algorithm;
-
   }
 
+  /**
+   * Finds an encryption key for this key
+   * @returns null if no encryption key has been found
+   */
+  this.getEncryptionKey = function() {
+    // V4: by convention subkeys are prefered for encryption service
+    // V3: keys MUST NOT have subkeys
+    var isValidSignKey = function(key) {
+      return key.algorithm != enums.read(enums.publicKey, enums.publicKey.dsa) 
+             && key.algorithm != enums.read(enums.publicKey, enums.publicKey.rsa_sign) 
+             //TODO verify key
+             //&& keys.verifyKey()
+    }
+    var subKeys = this.getSubkeys();
+
+    for (var j = 0; j < subKeys.length; j++) {
+      if (isValidSignKey(subKeys[j])) {
+        return subKeys[j];
+      }
+    }
+    // if no valid subkey for encryption, use primary key
+    var primaryKey = this.getKey();
+    if (isValidSignKey(primaryKey)) {
+      return primaryKey;  
+    }
+    return null;
+  }
+
+
+
   this.decrypt = function(passphrase) {
     var keys = this.getAllKeys();
 
     for (var i in keys)
-      if (keys[i].tag == openpgp_packet.tags.secret_subkey ||
-        keys[i].tag == openpgp_packet.tags.secret_key)
+      if (keys[i].tag == enums.packet.secret_subkey ||
+        keys[i].tag == enums.packet.secret_key)
 
         keys[i].decrypt(passphrase);
   }

src/openpgp.js

@@ -25,6 +25,9 @@ var armor = require('./encoding/armor.js');
 var packet = require('./packet');
 var util = require('./util');
 var enums = require('./enums.js');
+var crypto = require('./crypto');
+var key = require('./key.js');
+var config = require('./config');
 
 /**
  * GPG4Browsers Core interface. A single instance is hold
@@ -64,7 +67,45 @@ function _openpgp() {
     return packetList;
   }
 
-  function encryptMessage(publicKeyPacketlist, message) {
+  function encryptMessage(publicKeys, message) {
+
+    var packetList = new packet.list();
+
+    var literalDataPacket = new packet.literal();
+    literalDataPacket.set(message, 'utf8');
+
+    //TODO get preferred algo from signature
+    var sessionKey = crypto.generateSessionKey(enums.read(enums.symmetric, config.encryption_cipher));
+
+    publicKeys.forEach(function(publicKeyPacketlist) {
+      var pubKey = new key();
+      pubKey.packets = publicKeyPacketlist;
+      var encryptionKey = pubKey.getEncryptionKey();
+      if (encryptionKey) {
+        var pkESKeyPacket = new packet.public_key_encrypted_session_key();
+        pkESKeyPacket.publicKeyId = encryptionKey.getKeyId(); 
+        pkESKeyPacket.publicKeyAlgorithm = encryptionKey.algorithm;
+        pkESKeyPacket.sessionKey = sessionKey;
+        //TODO get preferred algo from signature
+        pkESKeyPacket.sessionKeyAlgorithm = enums.read(enums.symmetric, config.encryption_cipher);
+        pkESKeyPacket.encrypt(encryptionKey);
+        packetList.push(pkESKeyPacket);
+      }
+    });
+
+    var symEncryptedPacket; 
+    if (config.integrity_protect) {
+      symEncryptedPacket = new packet.sym_encrypted_integrity_protected();
+    } else {
+      symEncryptedPacket = new packet.symmetrically_encrypted();
+    }
+    symEncryptedPacket.packets = literalDataPacket;
+    //TODO get preferred algo from signature
+    symEncryptedPacket.encrypt(enums.read(enums.symmetric, config.encryption_cipher), sessionKey);
+    packetList.push(symEncryptedPacket);
+
+    var armored = armor.encode(3, packetList.write(), config);
+    return armored;
 
   }
 
@@ -318,7 +359,7 @@ function _openpgp() {
   this.generateKeyPair = generateKeyPair;
   this.write_signed_message = write_signed_message;
   this.write_signed_and_encrypted_message = write_signed_and_encrypted_message;
-  this.write_encrypted_message = write_encrypted_message;
+  this.encryptMessage = encryptMessage;
   this.readArmoredPackets = readArmoredPackets;
   this.readDearmoredPackets = readDearmoredPackets;
 }

src/packet/public_key.js

@@ -17,6 +17,7 @@
 
 var util = require('../util'),
   type_mpi = require('../type/mpi.js'),
+  type_keyid = require('../type/keyid.js'),
   enums = require('../enums.js'),
   crypto = require('../crypto');
 
@@ -122,7 +123,9 @@ module.exports = function packet_public_key() {
    * @return {String} A 8 byte key id
    */
   this.getKeyId = function() {
-    return this.getFingerprint().substr(12, 8);
+    var keyid = new type_keyid();
+    keyid.read(this.getFingerprint().substr(12, 8));
+    return keyid;
   }
 
   /**