michael@0: # This Source Code Form is subject to the terms of the Mozilla Public
michael@0: # License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0: # file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0: 
michael@0: 
michael@0: // A very thin wrapper around nsICryptoHash. It's not strictly
michael@0: // necessary, but makes the code a bit cleaner and gives us the
michael@0: // opportunity to verify that our implementations give the results that
michael@0: // we expect, for example if we have to interoperate with a server.
michael@0: //
michael@0: // The digest* methods reset the state of the hasher, so it's
michael@0: // necessary to call init() explicitly after them.
michael@0: //
michael@0: // Works only in Firefox 1.5+.
michael@0: //
michael@0: // IMPORTANT NOTE: Due to https://bugzilla.mozilla.org/show_bug.cgi?id=321024
michael@0: // you cannot use the cryptohasher before app-startup. The symptom of doing
michael@0: // so is a segfault in NSS.
michael@0: 
michael@0: /**
michael@0:  * Instantiate a new hasher. You must explicitly call init() before use!
michael@0:  */
michael@0: function G_CryptoHasher() {
michael@0:   this.debugZone = "cryptohasher";
michael@0:   this.hasher_ = null;
michael@0: }
michael@0: 
michael@0: G_CryptoHasher.algorithms = {
michael@0:   MD2: Ci.nsICryptoHash.MD2,
michael@0:   MD5: Ci.nsICryptoHash.MD5,
michael@0:   SHA1: Ci.nsICryptoHash.SHA1,
michael@0:   SHA256: Ci.nsICryptoHash.SHA256,
michael@0:   SHA384: Ci.nsICryptoHash.SHA384,
michael@0:   SHA512: Ci.nsICryptoHash.SHA512,
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Initialize the hasher. This function must be called after every call
michael@0:  * to one of the digest* methods.
michael@0:  *
michael@0:  * @param algorithm Constant from G_CryptoHasher.algorithms specifying the
michael@0:  *                  algorithm this hasher will use
michael@0:  */ 
michael@0: G_CryptoHasher.prototype.init = function(algorithm) {
michael@0:   var validAlgorithm = false;
michael@0:   for (var alg in G_CryptoHasher.algorithms)
michael@0:     if (algorithm == G_CryptoHasher.algorithms[alg])
michael@0:       validAlgorithm = true;
michael@0: 
michael@0:   if (!validAlgorithm)
michael@0:     throw new Error("Invalid algorithm: " + algorithm);
michael@0: 
michael@0:   this.hasher_ = Cc["@mozilla.org/security/hash;1"]
michael@0:                  .createInstance(Ci.nsICryptoHash);
michael@0:   this.hasher_.init(algorithm);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Update the hash's internal state with input given in a string. Can be
michael@0:  * called multiple times for incrementeal hash updates.
michael@0:  *
michael@0:  * @param input String containing data to hash.
michael@0:  */ 
michael@0: G_CryptoHasher.prototype.updateFromString = function(input) {
michael@0:   if (!this.hasher_)
michael@0:     throw new Error("You must initialize the hasher first!");
michael@0: 
michael@0:   var stream = Cc['@mozilla.org/io/string-input-stream;1']
michael@0:                .createInstance(Ci.nsIStringInputStream);
michael@0:   stream.setData(input, input.length);
michael@0:   this.updateFromStream(stream);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Update the hash's internal state with input given in an array. Can be
michael@0:  * called multiple times for incremental hash updates.
michael@0:  *
michael@0:  * @param input Array containing data to hash.
michael@0:  */ 
michael@0: G_CryptoHasher.prototype.updateFromArray = function(input) {
michael@0:   if (!this.hasher_)
michael@0:     throw new Error("You must initialize the hasher first!");
michael@0: 
michael@0:   this.hasher_.update(input, input.length);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Update the hash's internal state with input given in a stream. Can be
michael@0:  * called multiple times from incremental hash updates.
michael@0:  */
michael@0: G_CryptoHasher.prototype.updateFromStream = function(stream) {
michael@0:   if (!this.hasher_)
michael@0:     throw new Error("You must initialize the hasher first!");
michael@0: 
michael@0:   if (stream.available())
michael@0:     this.hasher_.updateFromStream(stream, stream.available());
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * @returns The hash value as a string (sequence of 8-bit values)
michael@0:  */ 
michael@0: G_CryptoHasher.prototype.digestRaw = function() {
michael@0:   var digest = this.hasher_.finish(false /* not b64 encoded */);
michael@0:   this.hasher_ = null;
michael@0:   return digest;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * @returns The hash value as a base64-encoded string
michael@0:  */ 
michael@0: G_CryptoHasher.prototype.digestBase64 = function() {
michael@0:   var digest = this.hasher_.finish(true /* b64 encoded */);
michael@0:   this.hasher_ = null;
michael@0:   return digest;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * @returns The hash value as a hex-encoded string
michael@0:  */ 
michael@0: G_CryptoHasher.prototype.digestHex = function() {
michael@0:   var raw = this.digestRaw();
michael@0:   return this.toHex_(raw);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Converts a sequence of values to a hex-encoded string. The input is a
michael@0:  * a string, so you can stick 16-bit values in each character.
michael@0:  *
michael@0:  * @param str String to conver to hex. (Often this is just a sequence of
michael@0:  *            16-bit values)
michael@0:  *
michael@0:  * @returns String containing the hex representation of the input
michael@0:  */ 
michael@0: G_CryptoHasher.prototype.toHex_ = function(str) {
michael@0:   var hexchars = '0123456789ABCDEF';
michael@0:   var hexrep = new Array(str.length * 2);
michael@0: 
michael@0:   for (var i = 0; i < str.length; ++i) {
michael@0:     hexrep[i * 2] = hexchars.charAt((str.charCodeAt(i) >> 4) & 15);
michael@0:     hexrep[i * 2 + 1] = hexchars.charAt(str.charCodeAt(i) & 15);
michael@0:   }
michael@0:   return hexrep.join('');
michael@0: }
michael@0: 
michael@0: #ifdef DEBUG
michael@0: /**
michael@0:  * Lame unittest function
michael@0:  */
michael@0: function TEST_G_CryptoHasher() {
michael@0:   if (G_GDEBUG) {
michael@0:     var z = "cryptohasher UNITTEST";
michael@0:     G_debugService.enableZone(z);
michael@0: 
michael@0:     G_Debug(z, "Starting");
michael@0: 
michael@0:     var md5 = function(str) {
michael@0:       var hasher = new G_CryptoHasher();
michael@0:       hasher.init(G_CryptoHasher.algorithms.MD5);
michael@0:       hasher.updateFromString(str);
michael@0:       return hasher.digestHex().toLowerCase();
michael@0:     };
michael@0: 
michael@0:     // test vectors from: http://www.faqs.org/rfcs/rfc1321.html
michael@0:     var vectors = {"": "d41d8cd98f00b204e9800998ecf8427e",
michael@0:                    "a": "0cc175b9c0f1b6a831c399e269772661",
michael@0:                    "abc": "900150983cd24fb0d6963f7d28e17f72",
michael@0:                    "message digest": "f96b697d7cb7938d525a2f31aaf161d0",
michael@0:                    "abcdefghijklmnopqrstuvwxyz": "c3fcd3d76192e4007dfb496cca67e13b",
michael@0:                    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789": "d174ab98d277d9f5a5611c2c9f419d9f",
michael@0:                    "12345678901234567890123456789012345678901234567890123456789012345678901234567890": "57edf4a22be3c955ac49da2e2107b67a"};
michael@0:                    
michael@0:     G_Debug(z, "PASSED");
michael@0:   }
michael@0: }
michael@0: #endif