sjcl-mini.js

/** @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 */

/**
 * The Stanford Javascript Crypto Library, top-level namespace.
 * @namespace
 */
var sjcl = {
  /**
   * Symmetric ciphers.
   * @namespace
   */
  cipher: {},

  /**
   * Hash functions.  Right now only SHA256 is implemented.
   * @namespace
   */
  hash: {},

  /**
   * Key exchange functions.  Right now only SRP is implemented.
   * @namespace
   */
  keyexchange: {},
  
  /**
   * Cipher modes of operation.
   * @namespace
   */
  mode: {},

  /**
   * Miscellaneous.  HMAC and PBKDF2.
   * @namespace
   */
  misc: {},
  
  /**
   * Bit array encoders and decoders.
   * @namespace
   *
   * @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: {},
  
  /**
   * Exceptions.
   * @namespace
   */
  exception: {
    /**
     * Ciphertext is corrupt.
     * @constructor
     */
    corrupt: function(message) {
      this.toString = function() { return "CORRUPT: "+this.message; };
      this.message = message;
    },
    
    /**
     * Invalid parameter.
     * @constructor
     */
    invalid: function(message) {
      this.toString = function() { return "INVALID: "+this.message; };
      this.message = message;
    },
    
    /**
     * Bug or missing feature in SJCL.
     * @constructor
     */
    bug: function(message) {
      this.toString = function() { return "BUG: "+this.message; };
      this.message = message;
    },

    /**
     * Something isn't ready.
     * @constructor
     */
    notReady: function(message) {
      this.toString = function() { return "NOT READY: "+this.message; };
      this.message = message;
    }
  }
};
/** @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.
 */
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
 */

/**
 * Arrays of bits, encoded as arrays of Numbers.
 * @namespace
 * @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} blength 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} [_end=0] 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
 */

/**
 * UTF-8 strings
 * @namespace
 */
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 >>> 8 >>> 8 >>> 8);
      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
 */

/**
 * Arrays of bytes
 * @namespace
 */
sjcl.codec.bytes = {
  /** Convert from a bitArray to an array of bytes. */
  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.push(tmp >>> 24);
      tmp <<= 8;
    }
    return out;
  },
  /** Convert from an array of bytes to a bitArray. */
  toBits: function (bytes) {
    var out = [], i, tmp=0;
    for (i=0; i<bytes.length; i++) {
      tmp = tmp << 8 | bytes[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 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
 */
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);
    if (nl > 9007199254740991){
      throw new sjcl.exception.invalid("Cannot hash more than 2^53 - 1 bits");
    }

    if (typeof Uint32Array !== 'undefined') {
	var c = new Uint32Array(b);
    	var j = 0;
    	for (i = 512+ol - ((512+ol) & 511); i <= nl; i+= 512) {
      	    this._block(c.subarray(16 * j, 16 * (j+1)));
      	    j += 1;
    	}
    	b.splice(0, 16 * j);
    } else {
	for (i = 512+ol - ((512+ol) & 511); 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, isPrime;

    function frac(x) { return (x-Math.floor(x)) * 0x100000000 | 0; }

    for (; i<64; prime++) {
      isPrime = true;
      for (factor=2; factor*factor <= prime; factor++) {
        if (prime % factor === 0) {
          isPrime = false;
          break;
        }
      }
      if (isPrime) {
        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 {Uint32Array|bitArray} w one block of words.
   * @private
   */
  _block:function (w) {  
    var i, tmp, a, b,
      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 Javascript SHA-1 implementation.
 *
 * Based on the implementation in RFC 3174, method 1, and on the SJCL
 * SHA-256 implementation.
 *
 * @author Quinn Slack
 */

/**
 * Context for a SHA-1 operation in progress.
 * @constructor
 */
sjcl.hash.sha1 = function (hash) {
  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 5 big-endian words.
 */
sjcl.hash.sha1.hash = function (data) {
  return (new sjcl.hash.sha1()).update(data).finalize();
};

sjcl.hash.sha1.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);
    if (nl > 9007199254740991){
      throw new sjcl.exception.invalid("Cannot hash more than 2^53 - 1 bits");
    }

    if (typeof Uint32Array !== 'undefined') {
	var c = new Uint32Array(b);
    	var j = 0;
    	for (i = this.blockSize+ol - ((this.blockSize+ol) & (this.blockSize-1)); i <= nl;
		i+= this.blockSize) {
      	    this._block(c.subarray(16 * j, 16 * (j+1)));
      	    j += 1;
    	}
    	b.splice(0, 16 * j);
    } else {
    	for (i = this.blockSize+ol - ((this.blockSize+ol) & (this.blockSize-1)); i <= nl;
             i+= this.blockSize) {
      	     this._block(b.splice(0,16));
      	}
    }
    return this;
  },
  
  /**
   * Complete hashing and output the hash value.
   * @return {bitArray} The hash value, an array of 5 big-endian words. TODO
   */
  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-1 initialization vector.
   * @private
   */
  _init:[0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0],

  /**
   * The SHA-1 hash key.
   * @private
   */
  _key:[0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6],

  /**
   * The SHA-1 logical functions f(0), f(1), ..., f(79).
   * @private
   */
  _f:function(t, b, c, d) {
    if (t <= 19) {
      return (b & c) | (~b & d);
    } else if (t <= 39) {
      return b ^ c ^ d;
    } else if (t <= 59) {
      return (b & c) | (b & d) | (c & d);
    } else if (t <= 79) {
      return b ^ c ^ d;
    }
  },

  /**
   * Circular left-shift operator.
   * @private
   */
  _S:function(n, x) {
    return (x << n) | (x >>> 32-n);
  },
  
  /**
   * Perform one cycle of SHA-1.
   * @param {Uint32Array|bitArray} words one block of words.
   * @private
   */
  _block:function (words) {
    var t, tmp, a, b, c, d, e,
    h = this._h;
    var w;
    if (typeof Uint32Array !== 'undefined') {
        // When words is passed to _block, it has 16 elements. SHA1 _block
        // function extends words with new elements (at the end there are 80 elements). 
        // The problem is that if we use Uint32Array instead of Array, 
        // the length of Uint32Array cannot be changed. Thus, we replace words with a 
        // normal Array here.
        w = Array(80); // do not use Uint32Array here as the instantiation is slower
        for (var j=0; j<16; j++){
            w[j] = words[j];
        }
    } else {
        w = words;
    }

    a = h[0]; b = h[1]; c = h[2]; d = h[3]; e = h[4]; 

    for (t=0; t<=79; t++) {
      if (t >= 16) {
        w[t] = this._S(1, w[t-3] ^ w[t-8] ^ w[t-14] ^ w[t-16]);
      }
      tmp = (this._S(5, a) + this._f(t, b, c, d) + e + w[t] +
             this._key[Math.floor(t/20)]) | 0;
      e = d;
      d = c;
      c = this._S(30, b);
      b = a;
      a = tmp;
   }

   h[0] = (h[0]+a) |0;
   h[1] = (h[1]+b) |0;
   h[2] = (h[2]+c) |0;
   h[3] = (h[3]+d) |0;
   h[4] = (h[4]+e) |0;
  }
};
/** @fileOverview Random number generator.
 *
 * @author Emily Stark
 * @author Mike Hamburg
 * @author Dan Boneh
 * @author Michael Brooks
 * @author Steve Thomas
 */

/** 
 * @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>
 * @constructor
 */
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 new sjcl.exception.invalid("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 = 0; i < data.length; i++) {
          tmp.push(data[i]);
        }
        data = tmp;
      } else {
        if (objName !== "[object Array]") {
          err = 1;
        }
        for (i=0; i<data.length && !err; i++) {
          if (typeof(data[i]) !== "number") {
            err = 1;
          }
        }
      }
      if (!err) {
        if (estimatedEntropy === undefined) {
          /* horrible entropy estimator */
          estimatedEntropy = 0;
          for (i=0; i<data.length; i++) {
            tmp= data[i];
            while (tmp>0) {
              estimatedEntropy++;
              tmp = tmp >>> 1;
            }
          }
        }
        this._pools[robin].update([id,this._eventId++,2,estimatedEntropy,t,data.length].concat(data));
      }
      break;
      
    case "string":
      if (estimatedEntropy === undefined) {
       /* English text has just over 1 bit per character of entropy.
        * But this might be HTML or something, and have far less
        * entropy than English...  Oh well, let's just say one bit.
        */
       estimatedEntropy = data.length;
      }
      this._pools[robin].update([id,this._eventId++,3,estimatedEntropy,t,data.length]);
      this._pools[robin].update(data);
      break;
      
    default:
      err=1;
    }
    if (err) {
      throw new sjcl.exception.bug("random: addEntropy only supports number, array of numbers or string");
    }
  
    /* record the new strength */
    this._poolEntropy[robin] += estimatedEntropy;
    this._poolStrength += estimatedEntropy;
  
    /* fire off events */
    if (oldReady === this._NOT_READY) {
      if (this.isReady() !== this._NOT_READY) {
        this._fireEvent("seeded", Math.max(this._strength, this._poolStrength));
      }
      this._fireEvent("progress", this.getProgress());
    }
  },
  
  /** Is the generator ready? */
  isReady: function (paranoia) {
    var entropyRequired = this._PARANOIA_LEVELS[ (paranoia !== undefined) ? paranoia : this._defaultParanoia ];
  
    if (this._strength && this._strength >= entropyRequired) {
      return (this._poolEntropy[0] > this._BITS_PER_RESEED && (new Date()).valueOf() > this._nextReseed) ?
        this._REQUIRES_RESEED | this._READY :
        this._READY;
    } else {
      return (this._poolStrength >= entropyRequired) ?
        this._REQUIRES_RESEED | this._NOT_READY :
        this._NOT_READY;
    }
  },
  
  /** Get the generator's progress toward readiness, as a fraction */
  getProgress: function (paranoia) {
    var entropyRequired = this._PARANOIA_LEVELS[ paranoia ? paranoia : this._defaultParanoia ];
  
    if (this._strength >= entropyRequired) {
      return 1.0;
    } else {
      return (this._poolStrength > entropyRequired) ?
        1.0 :
        this._poolStrength / entropyRequired;
    }
  },
  
  /** start the built-in entropy collectors */
  startCollectors: function () {
    if (this._collectorsStarted) { return; }
  
    this._eventListener = {
      loadTimeCollector: this._bind(this._loadTimeCollector),
      mouseCollector: this._bind(this._mouseCollector),
      keyboardCollector: this._bind(this._keyboardCollector),
      accelerometerCollector: this._bind(this._accelerometerCollector),
      touchCollector: this._bind(this._touchCollector)
    };

    if (window.addEventListener) {
      window.addEventListener("load", this._eventListener.loadTimeCollector, false);
      window.addEventListener("mousemove", this._eventListener.mouseCollector, false);
      window.addEventListener("keypress", this._eventListener.keyboardCollector, false);
      window.addEventListener("devicemotion", this._eventListener.accelerometerCollector, false);
      window.addEventListener("touchmove", this._eventListener.touchCollector, false);
    } else if (document.attachEvent) {
      document.attachEvent("onload", this._eventListener.loadTimeCollector);
      document.attachEvent("onmousemove", this._eventListener.mouseCollector);
      document.attachEvent("keypress", this._eventListener.keyboardCollector);
    } else {
      throw new sjcl.exception.bug("can't attach event");
    }
  
    this._collectorsStarted = true;
  },
  
  /** stop the built-in entropy collectors */
  stopCollectors: function () {
    if (!this._collectorsStarted) { return; }
  
    if (window.removeEventListener) {
      window.removeEventListener("load", this._eventListener.loadTimeCollector, false);
      window.removeEventListener("mousemove", this._eventListener.mouseCollector, false);
      window.removeEventListener("keypress", this._eventListener.keyboardCollector, false);
      window.removeEventListener("devicemotion", this._eventListener.accelerometerCollector, false);
      window.removeEventListener("touchmove", this._eventListener.touchCollector, false);
    } else if (document.detachEvent) {
      document.detachEvent("onload", this._eventListener.loadTimeCollector);
      document.detachEvent("onmousemove", this._eventListener.mouseCollector);
      document.detachEvent("keypress", this._eventListener.keyboardCollector);
    }

    this._collectorsStarted = false;
  },
  
  /* use a cookie to store entropy.
  useCookie: function (all_cookies) {
      throw new sjcl.exception.bug("random: useCookie is unimplemented");
  },*/
  
  /** add an event listener for progress or seeded-ness. */
  addEventListener: function (name, callback) {
    this._callbacks[name][this._callbackI++] = callback;
  },
  
  /** remove an event listener for progress or seeded-ness */
  removeEventListener: function (name, cb) {
    var i, j, cbs=this._callbacks[name], jsTemp=[];

    /* I'm not sure if this is necessary; in C++, iterating over a
     * collection and modifying it at the same time is a no-no.
     */

    for (j in cbs) {
      if (cbs.hasOwnProperty(j) && cbs[j] === cb) {
        jsTemp.push(j);
      }
    }

    for (i=0; i<jsTemp.length; i++) {
      j = jsTemp[i];
      delete cbs[j];
    }
  },
  
  _bind: function (func) {
    var that = this;
    return function () {
      func.apply(that, arguments);
    };
  },

  /** Generate 4 random words, no reseed, no gate.
   * @private
   */
  _gen4words: function () {
    for (var i=0; i<4; i++) {
      this._counter[i] = this._counter[i]+1 | 0;
      if (this._counter[i]) { break; }
    }
    return this._cipher.encrypt(this._counter);
  },
  
  /* Rekey the AES instance with itself after a request, or every _MAX_WORDS_PER_BURST words.
   * @private
   */
  _gate: function () {
    this._key = this._gen4words().concat(this._gen4words());
    this._cipher = new sjcl.cipher.aes(this._key);
  },
  
  /** Reseed the generator with the given words
   * @private
   */
  _reseed: function (seedWords) {
    this._key = sjcl.hash.sha256.hash(this._key.concat(seedWords));
    this._cipher = new sjcl.cipher.aes(this._key);
    for (var i=0; i<4; i++) {
      this._counter[i] = this._counter[i]+1 | 0;
      if (this._counter[i]) { break; }
    }
  },
  
  /** reseed the data from the entropy pools
   * @param full If set, use all the entropy pools in the reseed.
   */
  _reseedFromPools: function (full) {
    var reseedData = [], strength = 0, i;
  
    this._nextReseed = reseedData[0] =
      (new Date()).valueOf() + this._MILLISECONDS_PER_RESEED;
    
    for (i=0; i<16; i++) {
      /* On some browsers, this is cryptographically random.  So we might
       * as well toss it in the pot and stir...
       */
      reseedData.push(Math.random()*0x100000000|0);
    }
    
    for (i=0; i<this._pools.length; i++) {
     reseedData = reseedData.concat(this._pools[i].finalize());
     strength += this._poolEntropy[i];
     this._poolEntropy[i] = 0;
   
     if (!full && (this._reseedCount & (1<<i))) { break; }
    }
  
    /* if we used the last pool, push a new one onto the stack */
    if (this._reseedCount >= 1 << this._pools.length) {
     this._pools.push(new sjcl.hash.sha256());
     this._poolEntropy.push(0);
    }
  
    /* how strong was this reseed? */
    this._poolStrength -= strength;
    if (strength > this._strength) {
      this._strength = strength;
    }
  
    this._reseedCount ++;
    this._reseed(reseedData);
  },
  
  _keyboardCollector: function () {
    this._addCurrentTimeToEntropy(1);
  },
  
  _mouseCollector: function (ev) {
    var x, y;

    try {
      x = ev.x || ev.clientX || ev.offsetX || 0;
      y = ev.y || ev.clientY || ev.offsetY || 0;
    } catch (err) {
      // Event originated from a secure element. No mouse position available.
      x = 0;
      y = 0;
    }

    if (x != 0 && y!= 0) {
      this.addEntropy([x,y], 2, "mouse");
    }

    this._addCurrentTimeToEntropy(0);
  },

  _touchCollector: function(ev) {
    var touch = ev.touches[0] || ev.changedTouches[0];
    var x = touch.pageX || touch.clientX,
        y = touch.pageY || touch.clientY;

    this.addEntropy([x,y],1,"touch");

    this._addCurrentTimeToEntropy(0);
  },
  
  _loadTimeCollector: function () {
    this._addCurrentTimeToEntropy(2);
  },

  _addCurrentTimeToEntropy: function (estimatedEntropy) {
    if (typeof window !== 'undefined' && window.performance && typeof window.performance.now === "function") {
      //how much entropy do we want to add here?
      this.addEntropy(window.performance.now(), estimatedEntropy, "loadtime");
    } else {
      this.addEntropy((new Date()).valueOf(), estimatedEntropy, "loadtime");
    }
  },
  _accelerometerCollector: function (ev) {
    var ac = ev.accelerationIncludingGravity.x||ev.accelerationIncludingGravity.y||ev.accelerationIncludingGravity.z;
    if(window.orientation){
      var or = window.orientation;
      if (typeof or === "number") {
        this.addEntropy(or, 1, "accelerometer");
      }
    }
    if (ac) {
      this.addEntropy(ac, 2, "accelerometer");
    }
    this._addCurrentTimeToEntropy(0);
  },

  _fireEvent: function (name, arg) {
    var j, cbs=sjcl.random._callbacks[name], cbsTemp=[];
    /* TODO: there is a race condition between removing collectors and firing them */

    /* I'm not sure if this is necessary; in C++, iterating over a
     * collection and modifying it at the same time is a no-no.
     */

    for (j in cbs) {
      if (cbs.hasOwnProperty(j)) {
        cbsTemp.push(cbs[j]);
      }
    }

    for (j=0; j<cbsTemp.length; j++) {
      cbsTemp[j](arg);
    }
  }
};

/** an instance for the prng.
* @see sjcl.prng
*/
sjcl.random = new sjcl.prng(6);

(function(){
  // function for getting nodejs crypto module. catches and ignores errors.
  function getCryptoModule() {
    // XXX don't try to load the module. We don't want it for RN.
    return null;
  }

  try {
    var buf, crypt, ab;

    // get cryptographically strong entropy depending on runtime environment
    if (typeof module !== 'undefined' && module.exports && (crypt = getCryptoModule()) && crypt.randomBytes) {
      buf = crypt.randomBytes(1024/8);
      buf = new Uint32Array(new Uint8Array(buf).buffer);
      sjcl.random.addEntropy(buf, 1024, "crypto.randomBytes");

    } else if (typeof window !== 'undefined' && typeof Uint32Array !== 'undefined') {
      ab = new Uint32Array(32);
      if (window.crypto && window.crypto.getRandomValues) {
        window.crypto.getRandomValues(ab);
      } else if (window.msCrypto && window.msCrypto.getRandomValues) {
        window.msCrypto.getRandomValues(ab);
      } else {
        return;
      }

      // get cryptographically strong entropy in Webkit
      sjcl.random.addEntropy(ab, 1024, "crypto.getRandomValues");

    } else {
      // no getRandomValues :-(
    }
  } catch (e) {
    if (typeof window !== 'undefined' && window.console) {
      console.log("There was an error collecting entropy from the browser:");
      console.log(e);
      //we do not want the library to fail due to randomness not being maintained.
    }
  }
}());
if(typeof module !== 'undefined' && module.exports){
  module.exports = sjcl;
}
if (typeof define === "function") {
    define([], function () {
        return sjcl;
    });
}