nadachat
Version:
simple secure chat with end to end encyption
1,677 lines (1,463 loc) • 110 kB
JavaScript
/** @fileOverview Javascript cryptography implementation.
*
* Crush to remove comments, shorten variable names and
* generally reduce transmission size.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
"use strict";
/*jslint indent: 2, bitwise: false, nomen: false, plusplus: false, white: false, regexp: false */
/*global document, window, escape, unescape, module, require, Uint32Array */
/** @namespace The Stanford Javascript Crypto Library, top-level namespace. */
var sjcl = {
/** @namespace Symmetric ciphers. */
cipher: {},
/** @namespace Hash functions. Right now only SHA256 is implemented. */
hash: {},
/** @namespace Key exchange functions. Right now only SRP is implemented. */
keyexchange: {},
/** @namespace Block cipher modes of operation. */
mode: {},
/** @namespace Miscellaneous. HMAC and PBKDF2. */
misc: {},
/**
* @namespace Bit array encoders and decoders.
*
* @description
* The members of this namespace are functions which translate between
* SJCL's bitArrays and other objects (usually strings). Because it
* isn't always clear which direction is encoding and which is decoding,
* the method names are "fromBits" and "toBits".
*/
codec: {},
/** @namespace Exceptions. */
exception: {
/** @constructor Ciphertext is corrupt. */
corrupt: function(message) {
this.toString = function() { return "CORRUPT: "+this.message; };
this.message = message;
},
/** @constructor Invalid parameter. */
invalid: function(message) {
this.toString = function() { return "INVALID: "+this.message; };
this.message = message;
},
/** @constructor Bug or missing feature in SJCL. @constructor */
bug: function(message) {
this.toString = function() { return "BUG: "+this.message; };
this.message = message;
},
/** @constructor Something isn't ready. */
notReady: function(message) {
this.toString = function() { return "NOT READY: "+this.message; };
this.message = message;
}
}
};
if(typeof module !== 'undefined' && module.exports){
module.exports = sjcl;
}
if (typeof define === "function") {
define([], function () {
return sjcl;
});
}
/** @fileOverview Low-level AES implementation.
*
* This file contains a low-level implementation of AES, optimized for
* size and for efficiency on several browsers. It is based on
* OpenSSL's aes_core.c, a public-domain implementation by Vincent
* Rijmen, Antoon Bosselaers and Paulo Barreto.
*
* An older version of this implementation is available in the public
* domain, but this one is (c) Emily Stark, Mike Hamburg, Dan Boneh,
* Stanford University 2008-2010 and BSD-licensed for liability
* reasons.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/**
* Schedule out an AES key for both encryption and decryption. This
* is a low-level class. Use a cipher mode to do bulk encryption.
*
* @constructor
* @param {Array} key The key as an array of 4, 6 or 8 words.
*
* @class Advanced Encryption Standard (low-level interface)
*/
sjcl.cipher.aes = function (key) {
if (!this._tables[0][0][0]) {
this._precompute();
}
var i, j, tmp,
encKey, decKey,
sbox = this._tables[0][4], decTable = this._tables[1],
keyLen = key.length, rcon = 1;
if (keyLen !== 4 && keyLen !== 6 && keyLen !== 8) {
throw new sjcl.exception.invalid("invalid aes key size");
}
this._key = [encKey = key.slice(0), decKey = []];
// schedule encryption keys
for (i = keyLen; i < 4 * keyLen + 28; i++) {
tmp = encKey[i-1];
// apply sbox
if (i%keyLen === 0 || (keyLen === 8 && i%keyLen === 4)) {
tmp = sbox[tmp>>>24]<<24 ^ sbox[tmp>>16&255]<<16 ^ sbox[tmp>>8&255]<<8 ^ sbox[tmp&255];
// shift rows and add rcon
if (i%keyLen === 0) {
tmp = tmp<<8 ^ tmp>>>24 ^ rcon<<24;
rcon = rcon<<1 ^ (rcon>>7)*283;
}
}
encKey[i] = encKey[i-keyLen] ^ tmp;
}
// schedule decryption keys
for (j = 0; i; j++, i--) {
tmp = encKey[j&3 ? i : i - 4];
if (i<=4 || j<4) {
decKey[j] = tmp;
} else {
decKey[j] = decTable[0][sbox[tmp>>>24 ]] ^
decTable[1][sbox[tmp>>16 & 255]] ^
decTable[2][sbox[tmp>>8 & 255]] ^
decTable[3][sbox[tmp & 255]];
}
}
};
sjcl.cipher.aes.prototype = {
// public
/* Something like this might appear here eventually
name: "AES",
blockSize: 4,
keySizes: [4,6,8],
*/
/**
* Encrypt an array of 4 big-endian words.
* @param {Array} data The plaintext.
* @return {Array} The ciphertext.
*/
encrypt:function (data) { return this._crypt(data,0); },
/**
* Decrypt an array of 4 big-endian words.
* @param {Array} data The ciphertext.
* @return {Array} The plaintext.
*/
decrypt:function (data) { return this._crypt(data,1); },
/**
* The expanded S-box and inverse S-box tables. These will be computed
* on the client so that we don't have to send them down the wire.
*
* There are two tables, _tables[0] is for encryption and
* _tables[1] is for decryption.
*
* The first 4 sub-tables are the expanded S-box with MixColumns. The
* last (_tables[01][4]) is the S-box itself.
*
* @private
*/
_tables: [[[],[],[],[],[]],[[],[],[],[],[]]],
/**
* Expand the S-box tables.
*
* @private
*/
_precompute: function () {
var encTable = this._tables[0], decTable = this._tables[1],
sbox = encTable[4], sboxInv = decTable[4],
i, x, xInv, d=[], th=[], x2, x4, x8, s, tEnc, tDec;
// Compute double and third tables
for (i = 0; i < 256; i++) {
th[( d[i] = i<<1 ^ (i>>7)*283 )^i]=i;
}
for (x = xInv = 0; !sbox[x]; x ^= x2 || 1, xInv = th[xInv] || 1) {
// Compute sbox
s = xInv ^ xInv<<1 ^ xInv<<2 ^ xInv<<3 ^ xInv<<4;
s = s>>8 ^ s&255 ^ 99;
sbox[x] = s;
sboxInv[s] = x;
// Compute MixColumns
x8 = d[x4 = d[x2 = d[x]]];
tDec = x8*0x1010101 ^ x4*0x10001 ^ x2*0x101 ^ x*0x1010100;
tEnc = d[s]*0x101 ^ s*0x1010100;
for (i = 0; i < 4; i++) {
encTable[i][x] = tEnc = tEnc<<24 ^ tEnc>>>8;
decTable[i][s] = tDec = tDec<<24 ^ tDec>>>8;
}
}
// Compactify. Considerable speedup on Firefox.
for (i = 0; i < 5; i++) {
encTable[i] = encTable[i].slice(0);
decTable[i] = decTable[i].slice(0);
}
},
/**
* Encryption and decryption core.
* @param {Array} input Four words to be encrypted or decrypted.
* @param dir The direction, 0 for encrypt and 1 for decrypt.
* @return {Array} The four encrypted or decrypted words.
* @private
*/
_crypt:function (input, dir) {
if (input.length !== 4) {
throw new sjcl.exception.invalid("invalid aes block size");
}
var key = this._key[dir],
// state variables a,b,c,d are loaded with pre-whitened data
a = input[0] ^ key[0],
b = input[dir ? 3 : 1] ^ key[1],
c = input[2] ^ key[2],
d = input[dir ? 1 : 3] ^ key[3],
a2, b2, c2,
nInnerRounds = key.length/4 - 2,
i,
kIndex = 4,
out = [0,0,0,0],
table = this._tables[dir],
// load up the tables
t0 = table[0],
t1 = table[1],
t2 = table[2],
t3 = table[3],
sbox = table[4];
// Inner rounds. Cribbed from OpenSSL.
for (i = 0; i < nInnerRounds; i++) {
a2 = t0[a>>>24] ^ t1[b>>16 & 255] ^ t2[c>>8 & 255] ^ t3[d & 255] ^ key[kIndex];
b2 = t0[b>>>24] ^ t1[c>>16 & 255] ^ t2[d>>8 & 255] ^ t3[a & 255] ^ key[kIndex + 1];
c2 = t0[c>>>24] ^ t1[d>>16 & 255] ^ t2[a>>8 & 255] ^ t3[b & 255] ^ key[kIndex + 2];
d = t0[d>>>24] ^ t1[a>>16 & 255] ^ t2[b>>8 & 255] ^ t3[c & 255] ^ key[kIndex + 3];
kIndex += 4;
a=a2; b=b2; c=c2;
}
// Last round.
for (i = 0; i < 4; i++) {
out[dir ? 3&-i : i] =
sbox[a>>>24 ]<<24 ^
sbox[b>>16 & 255]<<16 ^
sbox[c>>8 & 255]<<8 ^
sbox[d & 255] ^
key[kIndex++];
a2=a; a=b; b=c; c=d; d=a2;
}
return out;
}
};
/** @fileOverview Arrays of bits, encoded as arrays of Numbers.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** @namespace Arrays of bits, encoded as arrays of Numbers.
*
* @description
* <p>
* These objects are the currency accepted by SJCL's crypto functions.
* </p>
*
* <p>
* Most of our crypto primitives operate on arrays of 4-byte words internally,
* but many of them can take arguments that are not a multiple of 4 bytes.
* This library encodes arrays of bits (whose size need not be a multiple of 8
* bits) as arrays of 32-bit words. The bits are packed, big-endian, into an
* array of words, 32 bits at a time. Since the words are double-precision
* floating point numbers, they fit some extra data. We use this (in a private,
* possibly-changing manner) to encode the number of bits actually present
* in the last word of the array.
* </p>
*
* <p>
* Because bitwise ops clear this out-of-band data, these arrays can be passed
* to ciphers like AES which want arrays of words.
* </p>
*/
sjcl.bitArray = {
/**
* Array slices in units of bits.
* @param {bitArray} a The array to slice.
* @param {Number} bstart The offset to the start of the slice, in bits.
* @param {Number} bend The offset to the end of the slice, in bits. If this is undefined,
* slice until the end of the array.
* @return {bitArray} The requested slice.
*/
bitSlice: function (a, bstart, bend) {
a = sjcl.bitArray._shiftRight(a.slice(bstart/32), 32 - (bstart & 31)).slice(1);
return (bend === undefined) ? a : sjcl.bitArray.clamp(a, bend-bstart);
},
/**
* Extract a number packed into a bit array.
* @param {bitArray} a The array to slice.
* @param {Number} bstart The offset to the start of the slice, in bits.
* @param {Number} length The length of the number to extract.
* @return {Number} The requested slice.
*/
extract: function(a, bstart, blength) {
// FIXME: this Math.floor is not necessary at all, but for some reason
// seems to suppress a bug in the Chromium JIT.
var x, sh = Math.floor((-bstart-blength) & 31);
if ((bstart + blength - 1 ^ bstart) & -32) {
// it crosses a boundary
x = (a[bstart/32|0] << (32 - sh)) ^ (a[bstart/32+1|0] >>> sh);
} else {
// within a single word
x = a[bstart/32|0] >>> sh;
}
return x & ((1<<blength) - 1);
},
/**
* Concatenate two bit arrays.
* @param {bitArray} a1 The first array.
* @param {bitArray} a2 The second array.
* @return {bitArray} The concatenation of a1 and a2.
*/
concat: function (a1, a2) {
if (a1.length === 0 || a2.length === 0) {
return a1.concat(a2);
}
var last = a1[a1.length-1], shift = sjcl.bitArray.getPartial(last);
if (shift === 32) {
return a1.concat(a2);
} else {
return sjcl.bitArray._shiftRight(a2, shift, last|0, a1.slice(0,a1.length-1));
}
},
/**
* Find the length of an array of bits.
* @param {bitArray} a The array.
* @return {Number} The length of a, in bits.
*/
bitLength: function (a) {
var l = a.length, x;
if (l === 0) { return 0; }
x = a[l - 1];
return (l-1) * 32 + sjcl.bitArray.getPartial(x);
},
/**
* Truncate an array.
* @param {bitArray} a The array.
* @param {Number} len The length to truncate to, in bits.
* @return {bitArray} A new array, truncated to len bits.
*/
clamp: function (a, len) {
if (a.length * 32 < len) { return a; }
a = a.slice(0, Math.ceil(len / 32));
var l = a.length;
len = len & 31;
if (l > 0 && len) {
a[l-1] = sjcl.bitArray.partial(len, a[l-1] & 0x80000000 >> (len-1), 1);
}
return a;
},
/**
* Make a partial word for a bit array.
* @param {Number} len The number of bits in the word.
* @param {Number} x The bits.
* @param {Number} [0] _end Pass 1 if x has already been shifted to the high side.
* @return {Number} The partial word.
*/
partial: function (len, x, _end) {
if (len === 32) { return x; }
return (_end ? x|0 : x << (32-len)) + len * 0x10000000000;
},
/**
* Get the number of bits used by a partial word.
* @param {Number} x The partial word.
* @return {Number} The number of bits used by the partial word.
*/
getPartial: function (x) {
return Math.round(x/0x10000000000) || 32;
},
/**
* Compare two arrays for equality in a predictable amount of time.
* @param {bitArray} a The first array.
* @param {bitArray} b The second array.
* @return {boolean} true if a == b; false otherwise.
*/
equal: function (a, b) {
if (sjcl.bitArray.bitLength(a) !== sjcl.bitArray.bitLength(b)) {
return false;
}
var x = 0, i;
for (i=0; i<a.length; i++) {
x |= a[i]^b[i];
}
return (x === 0);
},
/** Shift an array right.
* @param {bitArray} a The array to shift.
* @param {Number} shift The number of bits to shift.
* @param {Number} [carry=0] A byte to carry in
* @param {bitArray} [out=[]] An array to prepend to the output.
* @private
*/
_shiftRight: function (a, shift, carry, out) {
var i, last2=0, shift2;
if (out === undefined) { out = []; }
for (; shift >= 32; shift -= 32) {
out.push(carry);
carry = 0;
}
if (shift === 0) {
return out.concat(a);
}
for (i=0; i<a.length; i++) {
out.push(carry | a[i]>>>shift);
carry = a[i] << (32-shift);
}
last2 = a.length ? a[a.length-1] : 0;
shift2 = sjcl.bitArray.getPartial(last2);
out.push(sjcl.bitArray.partial(shift+shift2 & 31, (shift + shift2 > 32) ? carry : out.pop(),1));
return out;
},
/** xor a block of 4 words together.
* @private
*/
_xor4: function(x,y) {
return [x[0]^y[0],x[1]^y[1],x[2]^y[2],x[3]^y[3]];
},
/** byteswap a word array inplace.
* (does not handle partial words)
* @param {sjcl.bitArray} a word array
* @return {sjcl.bitArray} byteswapped array
*/
byteswapM: function(a) {
var i, v, m = 0xff00;
for (i = 0; i < a.length; ++i) {
v = a[i];
a[i] = (v >>> 24) | ((v >>> 8) & m) | ((v & m) << 8) | (v << 24);
}
return a;
}
};
/** @fileOverview Bit array codec implementations.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** @namespace UTF-8 strings */
sjcl.codec.utf8String = {
/** Convert from a bitArray to a UTF-8 string. */
fromBits: function (arr) {
var out = "", bl = sjcl.bitArray.bitLength(arr), i, tmp;
for (i=0; i<bl/8; i++) {
if ((i&3) === 0) {
tmp = arr[i/4];
}
out += String.fromCharCode(tmp >>> 24);
tmp <<= 8;
}
return decodeURIComponent(escape(out));
},
/** Convert from a UTF-8 string to a bitArray. */
toBits: function (str) {
str = unescape(encodeURIComponent(str));
var out = [], i, tmp=0;
for (i=0; i<str.length; i++) {
tmp = tmp << 8 | str.charCodeAt(i);
if ((i&3) === 3) {
out.push(tmp);
tmp = 0;
}
}
if (i&3) {
out.push(sjcl.bitArray.partial(8*(i&3), tmp));
}
return out;
}
};
/** @fileOverview Bit array codec implementations.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** @namespace Hexadecimal */
sjcl.codec.hex = {
/** Convert from a bitArray to a hex string. */
fromBits: function (arr) {
var out = "", i;
for (i=0; i<arr.length; i++) {
out += ((arr[i]|0)+0xF00000000000).toString(16).substr(4);
}
return out.substr(0, sjcl.bitArray.bitLength(arr)/4);//.replace(/(.{8})/g, "$1 ");
},
/** Convert from a hex string to a bitArray. */
toBits: function (str) {
var i, out=[], len;
str = str.replace(/\s|0x/g, "");
len = str.length;
str = str + "00000000";
for (i=0; i<str.length; i+=8) {
out.push(parseInt(str.substr(i,8),16)^0);
}
return sjcl.bitArray.clamp(out, len*4);
}
};
/** @fileOverview Bit array codec implementations.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** @namespace Base64 encoding/decoding */
sjcl.codec.base64 = {
/** The base64 alphabet.
* @private
*/
_chars: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
/** Convert from a bitArray to a base64 string. */
fromBits: function (arr, _noEquals, _url) {
var out = "", i, bits=0, c = sjcl.codec.base64._chars, ta=0, bl = sjcl.bitArray.bitLength(arr);
if (_url) {
c = c.substr(0,62) + '-_';
}
for (i=0; out.length * 6 < bl; ) {
out += c.charAt((ta ^ arr[i]>>>bits) >>> 26);
if (bits < 6) {
ta = arr[i] << (6-bits);
bits += 26;
i++;
} else {
ta <<= 6;
bits -= 6;
}
}
while ((out.length & 3) && !_noEquals) { out += "="; }
return out;
},
/** Convert from a base64 string to a bitArray */
toBits: function(str, _url) {
str = str.replace(/\s|=/g,'');
var out = [], i, bits=0, c = sjcl.codec.base64._chars, ta=0, x;
if (_url) {
c = c.substr(0,62) + '-_';
}
for (i=0; i<str.length; i++) {
x = c.indexOf(str.charAt(i));
if (x < 0) {
throw new sjcl.exception.invalid("this isn't base64!");
}
if (bits > 26) {
bits -= 26;
out.push(ta ^ x>>>bits);
ta = x << (32-bits);
} else {
bits += 6;
ta ^= x << (32-bits);
}
}
if (bits&56) {
out.push(sjcl.bitArray.partial(bits&56, ta, 1));
}
return out;
}
};
sjcl.codec.base64url = {
fromBits: function (arr) { return sjcl.codec.base64.fromBits(arr,1,1); },
toBits: function (str) { return sjcl.codec.base64.toBits(str,1); }
};
/** @fileOverview Javascript SHA-256 implementation.
*
* An older version of this implementation is available in the public
* domain, but this one is (c) Emily Stark, Mike Hamburg, Dan Boneh,
* Stanford University 2008-2010 and BSD-licensed for liability
* reasons.
*
* Special thanks to Aldo Cortesi for pointing out several bugs in
* this code.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/**
* Context for a SHA-256 operation in progress.
* @constructor
* @class Secure Hash Algorithm, 256 bits.
*/
sjcl.hash.sha256 = function (hash) {
if (!this._key[0]) { this._precompute(); }
if (hash) {
this._h = hash._h.slice(0);
this._buffer = hash._buffer.slice(0);
this._length = hash._length;
} else {
this.reset();
}
};
/**
* Hash a string or an array of words.
* @static
* @param {bitArray|String} data the data to hash.
* @return {bitArray} The hash value, an array of 16 big-endian words.
*/
sjcl.hash.sha256.hash = function (data) {
return (new sjcl.hash.sha256()).update(data).finalize();
};
sjcl.hash.sha256.prototype = {
/**
* The hash's block size, in bits.
* @constant
*/
blockSize: 512,
/**
* Reset the hash state.
* @return this
*/
reset:function () {
this._h = this._init.slice(0);
this._buffer = [];
this._length = 0;
return this;
},
/**
* Input several words to the hash.
* @param {bitArray|String} data the data to hash.
* @return this
*/
update: function (data) {
if (typeof data === "string") {
data = sjcl.codec.utf8String.toBits(data);
}
var i, b = this._buffer = sjcl.bitArray.concat(this._buffer, data),
ol = this._length,
nl = this._length = ol + sjcl.bitArray.bitLength(data);
for (i = 512+ol & -512; i <= nl; i+= 512) {
this._block(b.splice(0,16));
}
return this;
},
/**
* Complete hashing and output the hash value.
* @return {bitArray} The hash value, an array of 8 big-endian words.
*/
finalize:function () {
var i, b = this._buffer, h = this._h;
// Round out and push the buffer
b = sjcl.bitArray.concat(b, [sjcl.bitArray.partial(1,1)]);
// Round out the buffer to a multiple of 16 words, less the 2 length words.
for (i = b.length + 2; i & 15; i++) {
b.push(0);
}
// append the length
b.push(Math.floor(this._length / 0x100000000));
b.push(this._length | 0);
while (b.length) {
this._block(b.splice(0,16));
}
this.reset();
return h;
},
/**
* The SHA-256 initialization vector, to be precomputed.
* @private
*/
_init:[],
/*
_init:[0x6a09e667,0xbb67ae85,0x3c6ef372,0xa54ff53a,0x510e527f,0x9b05688c,0x1f83d9ab,0x5be0cd19],
*/
/**
* The SHA-256 hash key, to be precomputed.
* @private
*/
_key:[],
/*
_key:
[0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2],
*/
/**
* Function to precompute _init and _key.
* @private
*/
_precompute: function () {
var i = 0, prime = 2, factor;
function frac(x) { return (x-Math.floor(x)) * 0x100000000 | 0; }
outer: for (; i<64; prime++) {
for (factor=2; factor*factor <= prime; factor++) {
if (prime % factor === 0) {
// not a prime
continue outer;
}
}
if (i<8) {
this._init[i] = frac(Math.pow(prime, 1/2));
}
this._key[i] = frac(Math.pow(prime, 1/3));
i++;
}
},
/**
* Perform one cycle of SHA-256.
* @param {bitArray} words one block of words.
* @private
*/
_block:function (words) {
var i, tmp, a, b,
w = words.slice(0),
h = this._h,
k = this._key,
h0 = h[0], h1 = h[1], h2 = h[2], h3 = h[3],
h4 = h[4], h5 = h[5], h6 = h[6], h7 = h[7];
/* Rationale for placement of |0 :
* If a value can overflow is original 32 bits by a factor of more than a few
* million (2^23 ish), there is a possibility that it might overflow the
* 53-bit mantissa and lose precision.
*
* To avoid this, we clamp back to 32 bits by |'ing with 0 on any value that
* propagates around the loop, and on the hash state h[]. I don't believe
* that the clamps on h4 and on h0 are strictly necessary, but it's close
* (for h4 anyway), and better safe than sorry.
*
* The clamps on h[] are necessary for the output to be correct even in the
* common case and for short inputs.
*/
for (i=0; i<64; i++) {
// load up the input word for this round
if (i<16) {
tmp = w[i];
} else {
a = w[(i+1 ) & 15];
b = w[(i+14) & 15];
tmp = w[i&15] = ((a>>>7 ^ a>>>18 ^ a>>>3 ^ a<<25 ^ a<<14) +
(b>>>17 ^ b>>>19 ^ b>>>10 ^ b<<15 ^ b<<13) +
w[i&15] + w[(i+9) & 15]) | 0;
}
tmp = (tmp + h7 + (h4>>>6 ^ h4>>>11 ^ h4>>>25 ^ h4<<26 ^ h4<<21 ^ h4<<7) + (h6 ^ h4&(h5^h6)) + k[i]); // | 0;
// shift register
h7 = h6; h6 = h5; h5 = h4;
h4 = h3 + tmp | 0;
h3 = h2; h2 = h1; h1 = h0;
h0 = (tmp + ((h1&h2) ^ (h3&(h1^h2))) + (h1>>>2 ^ h1>>>13 ^ h1>>>22 ^ h1<<30 ^ h1<<19 ^ h1<<10)) | 0;
}
h[0] = h[0]+h0 | 0;
h[1] = h[1]+h1 | 0;
h[2] = h[2]+h2 | 0;
h[3] = h[3]+h3 | 0;
h[4] = h[4]+h4 | 0;
h[5] = h[5]+h5 | 0;
h[6] = h[6]+h6 | 0;
h[7] = h[7]+h7 | 0;
}
};
/** @fileOverview CCM mode implementation.
*
* Special thanks to Roy Nicholson for pointing out a bug in our
* implementation.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** @namespace CTR mode with CBC MAC. */
sjcl.mode.ccm = {
/** The name of the mode.
* @constant
*/
name: "ccm",
_progressListeners: [],
listenProgress: function (cb) {
sjcl.mode.ccm._progressListeners.push(cb);
},
unListenProgress: function (cb) {
var index = sjcl.mode.ccm._progressListeners.indexOf(cb);
if (index > -1) {
sjcl.mode.ccm._progressListeners.splice(index, 1);
}
},
_callProgressListener: function (val) {
var p = sjcl.mode.ccm._progressListeners.slice(), i;
for (i = 0; i < p.length; i += 1) {
p[i](val);
}
},
/** Encrypt in CCM mode.
* @static
* @param {Object} prf The pseudorandom function. It must have a block size of 16 bytes.
* @param {bitArray} plaintext The plaintext data.
* @param {bitArray} iv The initialization value.
* @param {bitArray} [adata=[]] The authenticated data.
* @param {Number} [tlen=64] the desired tag length, in bits.
* @return {bitArray} The encrypted data, an array of bytes.
*/
encrypt: function(prf, plaintext, iv, adata, tlen) {
var L, out = plaintext.slice(0), tag, w=sjcl.bitArray, ivl = w.bitLength(iv) / 8, ol = w.bitLength(out) / 8;
tlen = tlen || 64;
adata = adata || [];
if (ivl < 7) {
throw new sjcl.exception.invalid("ccm: iv must be at least 7 bytes");
}
// compute the length of the length
for (L=2; L<4 && ol >>> 8*L; L++) {}
if (L < 15 - ivl) { L = 15-ivl; }
iv = w.clamp(iv,8*(15-L));
// compute the tag
tag = sjcl.mode.ccm._computeTag(prf, plaintext, iv, adata, tlen, L);
// encrypt
out = sjcl.mode.ccm._ctrMode(prf, out, iv, tag, tlen, L);
return w.concat(out.data, out.tag);
},
/** Decrypt in CCM mode.
* @static
* @param {Object} prf The pseudorandom function. It must have a block size of 16 bytes.
* @param {bitArray} ciphertext The ciphertext data.
* @param {bitArray} iv The initialization value.
* @param {bitArray} [[]] adata The authenticated data.
* @param {Number} [64] tlen the desired tag length, in bits.
* @return {bitArray} The decrypted data.
*/
decrypt: function(prf, ciphertext, iv, adata, tlen) {
tlen = tlen || 64;
adata = adata || [];
var L,
w=sjcl.bitArray,
ivl = w.bitLength(iv) / 8,
ol = w.bitLength(ciphertext),
out = w.clamp(ciphertext, ol - tlen),
tag = w.bitSlice(ciphertext, ol - tlen), tag2;
ol = (ol - tlen) / 8;
if (ivl < 7) {
throw new sjcl.exception.invalid("ccm: iv must be at least 7 bytes");
}
// compute the length of the length
for (L=2; L<4 && ol >>> 8*L; L++) {}
if (L < 15 - ivl) { L = 15-ivl; }
iv = w.clamp(iv,8*(15-L));
// decrypt
out = sjcl.mode.ccm._ctrMode(prf, out, iv, tag, tlen, L);
// check the tag
tag2 = sjcl.mode.ccm._computeTag(prf, out.data, iv, adata, tlen, L);
if (!w.equal(out.tag, tag2)) {
throw new sjcl.exception.corrupt("ccm: tag doesn't match");
}
return out.data;
},
_macAdditionalData: function (prf, adata, iv, tlen, ol, L) {
var mac, tmp, i, macData = [], w=sjcl.bitArray, xor = w._xor4;
// mac the flags
mac = [w.partial(8, (adata.length ? 1<<6 : 0) | (tlen-2) << 2 | L-1)];
// mac the iv and length
mac = w.concat(mac, iv);
mac[3] |= ol;
mac = prf.encrypt(mac);
if (adata.length) {
// mac the associated data. start with its length...
tmp = w.bitLength(adata)/8;
if (tmp <= 0xFEFF) {
macData = [w.partial(16, tmp)];
} else if (tmp <= 0xFFFFFFFF) {
macData = w.concat([w.partial(16,0xFFFE)], [tmp]);
} // else ...
// mac the data itself
macData = w.concat(macData, adata);
for (i=0; i<macData.length; i += 4) {
mac = prf.encrypt(xor(mac, macData.slice(i,i+4).concat([0,0,0])));
}
}
return mac;
},
/* Compute the (unencrypted) authentication tag, according to the CCM specification
* @param {Object} prf The pseudorandom function.
* @param {bitArray} plaintext The plaintext data.
* @param {bitArray} iv The initialization value.
* @param {bitArray} adata The authenticated data.
* @param {Number} tlen the desired tag length, in bits.
* @return {bitArray} The tag, but not yet encrypted.
* @private
*/
_computeTag: function(prf, plaintext, iv, adata, tlen, L) {
// compute B[0]
var mac, i, w=sjcl.bitArray, xor = w._xor4;
tlen /= 8;
// check tag length and message length
if (tlen % 2 || tlen < 4 || tlen > 16) {
throw new sjcl.exception.invalid("ccm: invalid tag length");
}
if (adata.length > 0xFFFFFFFF || plaintext.length > 0xFFFFFFFF) {
// I don't want to deal with extracting high words from doubles.
throw new sjcl.exception.bug("ccm: can't deal with 4GiB or more data");
}
mac = sjcl.mode.ccm._macAdditionalData(prf, adata, iv, tlen, w.bitLength(plaintext)/8, L);
// mac the plaintext
for (i=0; i<plaintext.length; i+=4) {
mac = prf.encrypt(xor(mac, plaintext.slice(i,i+4).concat([0,0,0])));
}
return w.clamp(mac, tlen * 8);
},
/** CCM CTR mode.
* Encrypt or decrypt data and tag with the prf in CCM-style CTR mode.
* May mutate its arguments.
* @param {Object} prf The PRF.
* @param {bitArray} data The data to be encrypted or decrypted.
* @param {bitArray} iv The initialization vector.
* @param {bitArray} tag The authentication tag.
* @param {Number} tlen The length of th etag, in bits.
* @param {Number} L The CCM L value.
* @return {Object} An object with data and tag, the en/decryption of data and tag values.
* @private
*/
_ctrMode: function(prf, data, iv, tag, tlen, L) {
var enc, i, w=sjcl.bitArray, xor = w._xor4, ctr, l = data.length, bl=w.bitLength(data), n = l/50, p = n;
// start the ctr
ctr = w.concat([w.partial(8,L-1)],iv).concat([0,0,0]).slice(0,4);
// en/decrypt the tag
tag = w.bitSlice(xor(tag,prf.encrypt(ctr)), 0, tlen);
// en/decrypt the data
if (!l) { return {tag:tag, data:[]}; }
for (i=0; i<l; i+=4) {
if (i > n) {
sjcl.mode.ccm._callProgressListener(i/l);
n += p;
}
ctr[3]++;
enc = prf.encrypt(ctr);
data[i] ^= enc[0];
data[i+1] ^= enc[1];
data[i+2] ^= enc[2];
data[i+3] ^= enc[3];
}
return { tag:tag, data:w.clamp(data,bl) };
}
};
/** @fileOverview OCB 2.0 implementation
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** @namespace
* Phil Rogaway's Offset CodeBook mode, version 2.0.
* May be covered by US and international patents.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
sjcl.mode.ocb2 = {
/** The name of the mode.
* @constant
*/
name: "ocb2",
/** Encrypt in OCB mode, version 2.0.
* @param {Object} prp The block cipher. It must have a block size of 16 bytes.
* @param {bitArray} plaintext The plaintext data.
* @param {bitArray} iv The initialization value.
* @param {bitArray} [adata=[]] The authenticated data.
* @param {Number} [tlen=64] the desired tag length, in bits.
* @param [false] premac 1 if the authentication data is pre-macced with PMAC.
* @return The encrypted data, an array of bytes.
* @throws {sjcl.exception.invalid} if the IV isn't exactly 128 bits.
*/
encrypt: function(prp, plaintext, iv, adata, tlen, premac) {
if (sjcl.bitArray.bitLength(iv) !== 128) {
throw new sjcl.exception.invalid("ocb iv must be 128 bits");
}
var i,
times2 = sjcl.mode.ocb2._times2,
w = sjcl.bitArray,
xor = w._xor4,
checksum = [0,0,0,0],
delta = times2(prp.encrypt(iv)),
bi, bl,
output = [],
pad;
adata = adata || [];
tlen = tlen || 64;
for (i=0; i+4 < plaintext.length; i+=4) {
/* Encrypt a non-final block */
bi = plaintext.slice(i,i+4);
checksum = xor(checksum, bi);
output = output.concat(xor(delta,prp.encrypt(xor(delta, bi))));
delta = times2(delta);
}
/* Chop out the final block */
bi = plaintext.slice(i);
bl = w.bitLength(bi);
pad = prp.encrypt(xor(delta,[0,0,0,bl]));
bi = w.clamp(xor(bi.concat([0,0,0]),pad), bl);
/* Checksum the final block, and finalize the checksum */
checksum = xor(checksum,xor(bi.concat([0,0,0]),pad));
checksum = prp.encrypt(xor(checksum,xor(delta,times2(delta))));
/* MAC the header */
if (adata.length) {
checksum = xor(checksum, premac ? adata : sjcl.mode.ocb2.pmac(prp, adata));
}
return output.concat(w.concat(bi, w.clamp(checksum, tlen)));
},
/** Decrypt in OCB mode.
* @param {Object} prp The block cipher. It must have a block size of 16 bytes.
* @param {bitArray} ciphertext The ciphertext data.
* @param {bitArray} iv The initialization value.
* @param {bitArray} [adata=[]] The authenticated data.
* @param {Number} [tlen=64] the desired tag length, in bits.
* @param {boolean} [premac=false] true if the authentication data is pre-macced with PMAC.
* @return The decrypted data, an array of bytes.
* @throws {sjcl.exception.invalid} if the IV isn't exactly 128 bits.
* @throws {sjcl.exception.corrupt} if if the message is corrupt.
*/
decrypt: function(prp, ciphertext, iv, adata, tlen, premac) {
if (sjcl.bitArray.bitLength(iv) !== 128) {
throw new sjcl.exception.invalid("ocb iv must be 128 bits");
}
tlen = tlen || 64;
var i,
times2 = sjcl.mode.ocb2._times2,
w = sjcl.bitArray,
xor = w._xor4,
checksum = [0,0,0,0],
delta = times2(prp.encrypt(iv)),
bi, bl,
len = sjcl.bitArray.bitLength(ciphertext) - tlen,
output = [],
pad;
adata = adata || [];
for (i=0; i+4 < len/32; i+=4) {
/* Decrypt a non-final block */
bi = xor(delta, prp.decrypt(xor(delta, ciphertext.slice(i,i+4))));
checksum = xor(checksum, bi);
output = output.concat(bi);
delta = times2(delta);
}
/* Chop out and decrypt the final block */
bl = len-i*32;
pad = prp.encrypt(xor(delta,[0,0,0,bl]));
bi = xor(pad, w.clamp(ciphertext.slice(i),bl).concat([0,0,0]));
/* Checksum the final block, and finalize the checksum */
checksum = xor(checksum, bi);
checksum = prp.encrypt(xor(checksum, xor(delta, times2(delta))));
/* MAC the header */
if (adata.length) {
checksum = xor(checksum, premac ? adata : sjcl.mode.ocb2.pmac(prp, adata));
}
if (!w.equal(w.clamp(checksum, tlen), w.bitSlice(ciphertext, len))) {
throw new sjcl.exception.corrupt("ocb: tag doesn't match");
}
return output.concat(w.clamp(bi,bl));
},
/** PMAC authentication for OCB associated data.
* @param {Object} prp The block cipher. It must have a block size of 16 bytes.
* @param {bitArray} adata The authenticated data.
*/
pmac: function(prp, adata) {
var i,
times2 = sjcl.mode.ocb2._times2,
w = sjcl.bitArray,
xor = w._xor4,
checksum = [0,0,0,0],
delta = prp.encrypt([0,0,0,0]),
bi;
delta = xor(delta,times2(times2(delta)));
for (i=0; i+4<adata.length; i+=4) {
delta = times2(delta);
checksum = xor(checksum, prp.encrypt(xor(delta, adata.slice(i,i+4))));
}
bi = adata.slice(i);
if (w.bitLength(bi) < 128) {
delta = xor(delta,times2(delta));
bi = w.concat(bi,[0x80000000|0,0,0,0]);
}
checksum = xor(checksum, bi);
return prp.encrypt(xor(times2(xor(delta,times2(delta))), checksum));
},
/** Double a block of words, OCB style.
* @private
*/
_times2: function(x) {
return [x[0]<<1 ^ x[1]>>>31,
x[1]<<1 ^ x[2]>>>31,
x[2]<<1 ^ x[3]>>>31,
x[3]<<1 ^ (x[0]>>>31)*0x87];
}
};
/** @fileOverview GCM mode implementation.
*
* @author Juho Vähä-Herttua
*/
/** @namespace Galois/Counter mode. */
sjcl.mode.gcm = {
/** The name of the mode.
* @constant
*/
name: "gcm",
/** Encrypt in GCM mode.
* @static
* @param {Object} prf The pseudorandom function. It must have a block size of 16 bytes.
* @param {bitArray} plaintext The plaintext data.
* @param {bitArray} iv The initialization value.
* @param {bitArray} [adata=[]] The authenticated data.
* @param {Number} [tlen=128] The desired tag length, in bits.
* @return {bitArray} The encrypted data, an array of bytes.
*/
encrypt: function (prf, plaintext, iv, adata, tlen) {
var out, data = plaintext.slice(0), w=sjcl.bitArray;
tlen = tlen || 128;
adata = adata || [];
// encrypt and tag
out = sjcl.mode.gcm._ctrMode(true, prf, data, adata, iv, tlen);
return w.concat(out.data, out.tag);
},
/** Decrypt in GCM mode.
* @static
* @param {Object} prf The pseudorandom function. It must have a block size of 16 bytes.
* @param {bitArray} ciphertext The ciphertext data.
* @param {bitArray} iv The initialization value.
* @param {bitArray} [adata=[]] The authenticated data.
* @param {Number} [tlen=128] The desired tag length, in bits.
* @return {bitArray} The decrypted data.
*/
decrypt: function (prf, ciphertext, iv, adata, tlen) {
var out, data = ciphertext.slice(0), tag, w=sjcl.bitArray, l=w.bitLength(data);
tlen = tlen || 128;
adata = adata || [];
// Slice tag out of data
if (tlen <= l) {
tag = w.bitSlice(data, l-tlen);
data = w.bitSlice(data, 0, l-tlen);
} else {
tag = data;
data = [];
}
// decrypt and tag
out = sjcl.mode.gcm._ctrMode(false, prf, data, adata, iv, tlen);
if (!w.equal(out.tag, tag)) {
throw new sjcl.exception.corrupt("gcm: tag doesn't match");
}
return out.data;
},
/* Compute the galois multiplication of X and Y
* @private
*/
_galoisMultiply: function (x, y) {
var i, j, xi, Zi, Vi, lsb_Vi, w=sjcl.bitArray, xor=w._xor4;
Zi = [0,0,0,0];
Vi = y.slice(0);
// Block size is 128 bits, run 128 times to get Z_128
for (i=0; i<128; i++) {
xi = (x[Math.floor(i/32)] & (1 << (31-i%32))) !== 0;
if (xi) {
// Z_i+1 = Z_i ^ V_i
Zi = xor(Zi, Vi);
}
// Store the value of LSB(V_i)
lsb_Vi = (Vi[3] & 1) !== 0;
// V_i+1 = V_i >> 1
for (j=3; j>0; j--) {
Vi[j] = (Vi[j] >>> 1) | ((Vi[j-1]&1) << 31);
}
Vi[0] = Vi[0] >>> 1;
// If LSB(V_i) is 1, V_i+1 = (V_i >> 1) ^ R
if (lsb_Vi) {
Vi[0] = Vi[0] ^ (0xe1 << 24);
}
}
return Zi;
},
_ghash: function(H, Y0, data) {
var Yi, i, l = data.length;
Yi = Y0.slice(0);
for (i=0; i<l; i+=4) {
Yi[0] ^= 0xffffffff&data[i];
Yi[1] ^= 0xffffffff&data[i+1];
Yi[2] ^= 0xffffffff&data[i+2];
Yi[3] ^= 0xffffffff&data[i+3];
Yi = sjcl.mode.gcm._galoisMultiply(Yi, H);
}
return Yi;
},
/** GCM CTR mode.
* Encrypt or decrypt data and tag with the prf in GCM-style CTR mode.
* @param {Boolean} encrypt True if encrypt, false if decrypt.
* @param {Object} prf The PRF.
* @param {bitArray} data The data to be encrypted or decrypted.
* @param {bitArray} iv The initialization vector.
* @param {bitArray} adata The associated data to be tagged.
* @param {Number} tlen The length of the tag, in bits.
*/
_ctrMode: function(encrypt, prf, data, adata, iv, tlen) {
var H, J0, S0, enc, i, ctr, tag, last, l, bl, abl, ivbl, w=sjcl.bitArray;
// Calculate data lengths
l = data.length;
bl = w.bitLength(data);
abl = w.bitLength(adata);
ivbl = w.bitLength(iv);
// Calculate the parameters
H = prf.encrypt([0,0,0,0]);
if (ivbl === 96) {
J0 = iv.slice(0);
J0 = w.concat(J0, [1]);
} else {
J0 = sjcl.mode.gcm._ghash(H, [0,0,0,0], iv);
J0 = sjcl.mode.gcm._ghash(H, J0, [0,0,Math.floor(ivbl/0x100000000),ivbl&0xffffffff]);
}
S0 = sjcl.mode.gcm._ghash(H, [0,0,0,0], adata);
// Initialize ctr and tag
ctr = J0.slice(0);
tag = S0.slice(0);
// If decrypting, calculate hash
if (!encrypt) {
tag = sjcl.mode.gcm._ghash(H, S0, data);
}
// Encrypt all the data
for (i=0; i<l; i+=4) {
ctr[3]++;
enc = prf.encrypt(ctr);
data[i] ^= enc[0];
data[i+1] ^= enc[1];
data[i+2] ^= enc[2];
data[i+3] ^= enc[3];
}
data = w.clamp(data, bl);
// If encrypting, calculate hash
if (encrypt) {
tag = sjcl.mode.gcm._ghash(H, S0, data);
}
// Calculate last block from bit lengths, ugly because bitwise operations are 32-bit
last = [
Math.floor(abl/0x100000000), abl&0xffffffff,
Math.floor(bl/0x100000000), bl&0xffffffff
];
// Calculate the final tag block
tag = sjcl.mode.gcm._ghash(H, tag, last);
enc = prf.encrypt(J0);
tag[0] ^= enc[0];
tag[1] ^= enc[1];
tag[2] ^= enc[2];
tag[3] ^= enc[3];
return { tag:w.bitSlice(tag, 0, tlen), data:data };
}
};
/** @fileOverview HMAC implementation.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** HMAC with the specified hash function.
* @constructor
* @param {bitArray} key the key for HMAC.
* @param {Object} [hash=sjcl.hash.sha256] The hash function to use.
*/
sjcl.misc.hmac = function (key, Hash) {
this._hash = Hash = Hash || sjcl.hash.sha256;
var exKey = [[],[]], i,
bs = Hash.prototype.blockSize / 32;
this._baseHash = [new Hash(), new Hash()];
if (key.length > bs) {
key = Hash.hash(key);
}
for (i=0; i<bs; i++) {
exKey[0][i] = key[i]^0x36363636;
exKey[1][i] = key[i]^0x5C5C5C5C;
}
this._baseHash[0].update(exKey[0]);
this._baseHash[1].update(exKey[1]);
this._resultHash = new Hash(this._baseHash[0]);
};
/** HMAC with the specified hash function. Also called encrypt since it's a prf.
* @param {bitArray|String} data The data to mac.
*/
sjcl.misc.hmac.prototype.encrypt = sjcl.misc.hmac.prototype.mac = function (data) {
if (!this._updated) {
this.update(data);
return this.digest(data);
} else {
throw new sjcl.exception.invalid("encrypt on already updated hmac called!");
}
};
sjcl.misc.hmac.prototype.reset = function () {
this._resultHash = new this._hash(this._baseHash[0]);
this._updated = false;
};
sjcl.misc.hmac.prototype.update = function (data) {
this._updated = true;
this._resultHash.update(data);
};
sjcl.misc.hmac.prototype.digest = function () {
var w = this._resultHash.finalize(), result = new (this._hash)(this._baseHash[1]).update(w).finalize();
this.reset();
return result;
};/** @fileOverview Password-based key-derivation function, version 2.0.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/** Password-Based Key-Derivation Function, version 2.0.
*
* Generate keys from passwords using PBKDF2-HMAC-SHA256.
*
* This is the method specified by RSA's PKCS #5 standard.
*
* @param {bitArray|String} password The password.
* @param {bitArray|String} salt The salt. Should have lots of entropy.
* @param {Number} [count=1000] The number of iterations. Higher numbers make the function slower but more secure.
* @param {Number} [length] The length of the derived key. Defaults to the
output size of the hash function.
* @param {Object} [Prff=sjcl.misc.hmac] The pseudorandom function family.
* @return {bitArray} the derived key.
*/
sjcl.misc.pbkdf2 = function (password, salt, count, length, Prff) {
count = count || 1000;
if (length < 0 || count < 0) {
throw sjcl.exception.invalid("invalid params to pbkdf2");
}
if (typeof password === "string") {
password = sjcl.codec.utf8String.toBits(password);
}
if (typeof salt === "string") {
salt = sjcl.codec.utf8String.toBits(salt);
}
Prff = Prff || sjcl.misc.hmac;
var prf = new Prff(password),
u, ui, i, j, k, out = [], b = sjcl.bitArray;
for (k = 1; 32 * out.length < (length || 1); k++) {
u = ui = prf.encrypt(b.concat(salt,[k]));
for (i=1; i<count; i++) {
ui = prf.encrypt(ui);
for (j=0; j<ui.length; j++) {
u[j] ^= ui[j];
}
}
out = out.concat(u);
}
if (length) { out = b.clamp(out, length); }
return out;
};
/** @fileOverview Random number generator.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
* @author Michael Brooks
*/
/** @constructor
* @class Random number generator
* @description
* <b>Use sjcl.random as a singleton for this class!</b>
* <p>
* This random number generator is a derivative of Ferguson and Schneier's
* generator Fortuna. It collects entropy from various events into several
* pools, implemented by streaming SHA-256 instances. It differs from
* ordinary Fortuna in a few ways, though.
* </p>
*
* <p>
* Most importantly, it has an entropy estimator. This is present because
* there is a strong conflict here between making the generator available
* as soon as possible, and making sure that it doesn't "run on empty".
* In Fortuna, there is a saved state file, and the system is likely to have
* time to warm up.
* </p>
*
* <p>
* Second, because users are unlikely to stay on the page for very long,
* and to speed startup time, the number of pools increases logarithmically:
* a new pool is created when the previous one is actually used for a reseed.
* This gives the same asymptotic guarantees as Fortuna, but gives more
* entropy to early reseeds.
* </p>
*
* <p>
* The entire mechanism here feels pretty klunky. Furthermore, there are
* several improvements that should be made, including support for
* dedicated cryptographic functions that may be present in some browsers;
* state files in local storage; cookies containing randomness; etc. So
* look for improvements in future versions.
* </p>
*/
sjcl.prng = function(defaultParanoia) {
/* private */
this._pools = [new sjcl.hash.sha256()];
this._poolEntropy = [0];
this._reseedCount = 0;
this._robins = {};
this._eventId = 0;
this._collectorIds = {};
this._collectorIdNext = 0;
this._strength = 0;
this._poolStrength = 0;
this._nextReseed = 0;
this._key = [0,0,0,0,0,0,0,0];
this._counter = [0,0,0,0];
this._cipher = undefined;
this._defaultParanoia = defaultParanoia;
/* event listener stuff */
this._collectorsStarted = false;
this._callbacks = {progress: {}, seeded: {}};
this._callbackI = 0;
/* constants */
this._NOT_READY = 0;
this._READY = 1;
this._REQUIRES_RESEED = 2;
this._MAX_WORDS_PER_BURST = 65536;
this._PARANOIA_LEVELS = [0,48,64,96,128,192,256,384,512,768,1024];
this._MILLISECONDS_PER_RESEED = 30000;
this._BITS_PER_RESEED = 80;
};
sjcl.prng.prototype = {
/** Generate several random words, and return them in an array.
* A word consists of 32 bits (4 bytes)
* @param {Number} nwords The number of words to generate.
*/
randomWords: function (nwords, paranoia) {
var out = [], i, readiness = this.isReady(paranoia), g;
if (readiness === this._NOT_READY) {
throw new sjcl.exception.notReady("generator isn't seeded");
} else if (readiness & this._REQUIRES_RESEED) {
this._reseedFromPools(!(readiness & this._READY));
}
for (i=0; i<nwords; i+= 4) {
if ((i+1) % this._MAX_WORDS_PER_BURST === 0) {
this._gate();
}
g = this._gen4words();
out.push(g[0],g[1],g[2],g[3]);
}
this._gate();
return out.slice(0,nwords);
},
setDefaultParanoia: function (paranoia, allowZeroParanoia) {
if (paranoia === 0 && allowZeroParanoia !== "Setting paranoia=0 will ruin your security; use it only for testing") {
throw "Setting paranoia=0 will ruin your security; use it only for testing";
}
this._defaultParanoia = paranoia;
},
/**
* Add entropy to the pools.
* @param data The entropic value. Should be a 32-bit integer, array of 32-bit integers, or string
* @param {Number} estimatedEntropy The estimated entropy of data, in bits
* @param {String} source The source of the entropy, eg "mouse"
*/
addEntropy: function (data, estimatedEntropy, source) {
source = source || "user";
var id,
i, tmp,
t = (new Date()).valueOf(),
robin = this._robins[source],
oldReady = this.isReady(), err = 0, objName;
id = this._collectorIds[source];
if (id === undefined) { id = this._collectorIds[source] = this._collectorIdNext ++; }
if (robin === undefined) { robin = this._robins[source] = 0; }
this._robins[source] = ( this._robins[source] + 1 ) % this._pools.length;
switch(typeof(data)) {
case "number":
if (estimatedEntropy === undefined) {
estimatedEntropy = 1;
}
this._pools[robin].update([id,this._eventId++,1,estimatedEntropy,t,1,data|0]);
break;
case "object":
objName = Object.prototype.toString.call(data);
if (objName === "[object Uint32Array]") {
tmp = [];
for (i =