assets_js_lib_sjcl.js

// Select components from sjcl to suit the crypto operations bip39 requires.

//// base.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 */

/** @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;
    });
}


//// bitArray.js

/** @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;
  }
};


//// codecString.js

/** @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;
  }
};


//// codecHex.js

/** @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
 */

/**
 * Base64 encoding/decoding 
 * @namespace
 */
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 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 GCM mode implementation.
 *
 * @author Juho Vähä-Herttua
 */

/**
 * Galois/Counter mode.
 * @namespace
 */ 
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 };
  }
};


//// sha512.js

/** @fileOverview Javascript SHA-512 implementation.
 *
 * This implementation was written for CryptoJS by Jeff Mott and adapted for
 * SJCL by Stefan Thomas.
 *
 * CryptoJS (c) 2009–2012 by Jeff Mott. All rights reserved.
 * Released with New BSD License
 *
 * @author Emily Stark
 * @author Mike Hamburg
 * @author Dan Boneh
 * @author Jeff Mott
 * @author Stefan Thomas
 */

/**
 * Context for a SHA-512 operation in progress.
 * @constructor
 * @class Secure Hash Algorithm, 512 bits.
 */
sjcl.hash.sha512 = 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.sha512.hash = function (data) {
  return (new sjcl.hash.sha512()).update(data).finalize();
};

sjcl.hash.sha512.prototype = {
  /**
   * The hash's block size, in bits.
   * @constant
   */
  blockSize: 1024,

  /**
   * 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 = 1024+ol & -1024; i <= nl; i+= 1024) {
      this._block(b.splice(0,32));
    }
    return this;
  },

  /**
   * Complete hashing and output the hash value.
   * @return {bitArray} The hash value, an array of 16 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 32 words, less the 4 length words.
    for (i = b.length + 4; i & 31; i++) {
      b.push(0);
    }

    // append the length
    b.push(0);
    b.push(0);
    b.push(Math.floor(this._length / 0x100000000));
    b.push(this._length | 0);

    while (b.length) {
      this._block(b.splice(0,32));
    }

    this.reset();
    return h;
  },

  /**
   * The SHA-512 initialization vector, to be precomputed.
   * @private
   */
  _init:[],

  /**
   * Least significant 24 bits of SHA512 initialization values.
   *
   * Javascript only has 53 bits of precision, so we compute the 40 most
   * significant bits and add the remaining 24 bits as constants.
   *
   * @private
   */
  _initr: [ 0xbcc908, 0xcaa73b, 0x94f82b, 0x1d36f1, 0xe682d1, 0x3e6c1f, 0x41bd6b, 0x7e2179 ],

  /*
  _init:
  [0x6a09e667, 0xf3bcc908, 0xbb67ae85, 0x84caa73b, 0x3c6ef372, 0xfe94f82b, 0xa54ff53a, 0x5f1d36f1,
   0x510e527f, 0xade682d1, 0x9b05688c, 0x2b3e6c1f, 0x1f83d9ab, 0xfb41bd6b, 0x5be0cd19, 0x137e2179],
  */

  /**
   * The SHA-512 hash key, to be precomputed.
   * @private
   */
  _key:[],

  /**
   * Least significant 24 bits of SHA512 key values.
   * @private
   */
  _keyr:
  [0x28ae22, 0xef65cd, 0x4d3b2f, 0x89dbbc, 0x48b538, 0x05d019, 0x194f9b, 0x6d8118,
   0x030242, 0x706fbe, 0xe4b28c, 0xffb4e2, 0x7b896f, 0x1696b1, 0xc71235, 0x692694,
   0xf14ad2, 0x4f25e3, 0x8cd5b5, 0xac9c65, 0x2b0275, 0xa6e483, 0x41fbd4, 0x1153b5,
   0x66dfab, 0xb43210, 0xfb213f, 0xef0ee4, 0xa88fc2, 0x0aa725, 0x03826f, 0x0e6e70,
   0xd22ffc, 0x26c926, 0xc42aed, 0x95b3df, 0xaf63de, 0x77b2a8, 0xedaee6, 0x82353b,
   0xf10364, 0x423001, 0xf89791, 0x54be30, 0xef5218, 0x65a910, 0x71202a, 0xbbd1b8,
   0xd2d0c8, 0x41ab53, 0x8eeb99, 0x9b48a8, 0xc95a63, 0x418acb, 0x63e373, 0xb2b8a3,
   0xefb2fc, 0x172f60, 0xf0ab72, 0x6439ec, 0x631e28, 0x82bde9, 0xc67915, 0x72532b,
   0x26619c, 0xc0c207, 0xe0eb1e, 0x6ed178, 0x176fba, 0xc898a6, 0xf90dae, 0x1c471b,
   0x047d84, 0xc72493, 0xc9bebc, 0x100d4c, 0x3e42b6, 0x657e2a, 0xd6faec, 0x475817],

  /*
  _key:
  [0x428a2f98, 0xd728ae22, 0x71374491, 0x23ef65cd, 0xb5c0fbcf, 0xec4d3b2f, 0xe9b5dba5, 0x8189dbbc,
   0x3956c25b, 0xf348b538, 0x59f111f1, 0xb605d019, 0x923f82a4, 0xaf194f9b, 0xab1c5ed5, 0xda6d8118,
   0xd807aa98, 0xa3030242, 0x12835b01, 0x45706fbe, 0x243185be, 0x4ee4b28c, 0x550c7dc3, 0xd5ffb4e2,
   0x72be5d74, 0xf27b896f, 0x80deb1fe, 0x3b1696b1, 0x9bdc06a7, 0x25c71235, 0xc19bf174, 0xcf692694,
   0xe49b69c1, 0x9ef14ad2, 0xefbe4786, 0x384f25e3, 0x0fc19dc6, 0x8b8cd5b5, 0x240ca1cc, 0x77ac9c65,
   0x2de92c6f, 0x592b0275, 0x4a7484aa, 0x6ea6e483, 0x5cb0a9dc, 0xbd41fbd4, 0x76f988da, 0x831153b5,
   0x983e5152, 0xee66dfab, 0xa831c66d, 0x2db43210, 0xb00327c8, 0x98fb213f, 0xbf597fc7, 0xbeef0ee4,
   0xc6e00bf3, 0x3da88fc2, 0xd5a79147, 0x930aa725, 0x06ca6351, 0xe003826f, 0x14292967, 0x0a0e6e70,
   0x27b70a85, 0x46d22ffc, 0x2e1b2138, 0x5c26c926, 0x4d2c6dfc, 0x5ac42aed, 0x53380d13, 0x9d95b3df,
   0x650a7354, 0x8baf63de, 0x766a0abb, 0x3c77b2a8, 0x81c2c92e, 0x47edaee6, 0x92722c85, 0x1482353b,
   0xa2bfe8a1, 0x4cf10364, 0xa81a664b, 0xbc423001, 0xc24b8b70, 0xd0f89791, 0xc76c51a3, 0x0654be30,
   0xd192e819, 0xd6ef5218, 0xd6990624, 0x5565a910, 0xf40e3585, 0x5771202a, 0x106aa070, 0x32bbd1b8,
   0x19a4c116, 0xb8d2d0c8, 0x1e376c08, 0x5141ab53, 0x2748774c, 0xdf8eeb99, 0x34b0bcb5, 0xe19b48a8,
   0x391c0cb3, 0xc5c95a63, 0x4ed8aa4a, 0xe3418acb, 0x5b9cca4f, 0x7763e373, 0x682e6ff3, 0xd6b2b8a3,
   0x748f82ee, 0x5defb2fc, 0x78a5636f, 0x43172f60, 0x84c87814, 0xa1f0ab72, 0x8cc70208, 0x1a6439ec,
   0x90befffa, 0x23631e28, 0xa4506ceb, 0xde82bde9, 0xbef9a3f7, 0xb2c67915, 0xc67178f2, 0xe372532b,
   0xca273ece, 0xea26619c, 0xd186b8c7, 0x21c0c207, 0xeada7dd6, 0xcde0eb1e, 0xf57d4f7f, 0xee6ed178,
   0x06f067aa, 0x72176fba, 0x0a637dc5, 0xa2c898a6, 0x113f9804, 0xbef90dae, 0x1b710b35, 0x131c471b,
   0x28db77f5, 0x23047d84, 0x32caab7b, 0x40c72493, 0x3c9ebe0a, 0x15c9bebc, 0x431d67c4, 0x9c100d4c,
   0x4cc5d4be, 0xcb3e42b6, 0x597f299c, 0xfc657e2a, 0x5fcb6fab, 0x3ad6faec, 0x6c44198c, 0x4a475817],
  */

  /**
   * Function to precompute _init and _key.
   * @private
   */
  _precompute: function () {
    // XXX: This code is for precomputing the SHA256 constants, change for
    //      SHA512 and re-enable.
    var i = 0, prime = 2, factor;

    function frac(x)  { return (x-Math.floor(x)) * 0x100000000 | 0; }
    function frac2(x) { return (x-Math.floor(x)) * 0x10000000000 & 0xff; }

    outer: for (; i<80; prime++) {
      for (factor=2; factor*factor <= prime; factor++) {
        if (prime % factor === 0) {
          // not a prime
          continue outer;
        }
      }

      if (i<8) {
        this._init[i*2] = frac(Math.pow(prime, 1/2));
        this._init[i*2+1] = (frac2(Math.pow(prime, 1/2)) << 24) | this._initr[i];
      }
      this._key[i*2] = frac(Math.pow(prime, 1/3));
      this._key[i*2+1] = (frac2(Math.pow(prime, 1/3)) << 24) | this._keyr[i];
      i++;
    }
  },

  /**
   * Perform one cycle of SHA-512.
   * @param {bitArray} words one block of words.
   * @private
   */
  _block:function (words) {
    var i, wrh, wrl,
        w = words.slice(0),
        h = this._h,
        k = this._key,
        h0h = h[ 0], h0l = h[ 1], h1h = h[ 2], h1l = h[ 3],
        h2h = h[ 4], h2l = h[ 5], h3h = h[ 6], h3l = h[ 7],
        h4h = h[ 8], h4l = h[ 9], h5h = h[10], h5l = h[11],
        h6h = h[12], h6l = h[13], h7h = h[14], h7l = h[15];

    // Working variables
    var ah = h0h, al = h0l, bh = h1h, bl = h1l,
        ch = h2h, cl = h2l, dh = h3h, dl = h3l,
        eh = h4h, el = h4l, fh = h5h, fl = h5l,
        gh = h6h, gl = h6l, hh = h7h, hl = h7l;

    for (i=0; i<80; i++) {
      // load up the input word for this round
      if (i<16) {
        wrh = w[i * 2];
        wrl = w[i * 2 + 1];
      } else {
        // Gamma0
        var gamma0xh = w[(i-15) * 2];
        var gamma0xl = w[(i-15) * 2 + 1];
        var gamma0h =
          ((gamma0xl << 31) | (gamma0xh >>> 1)) ^
          ((gamma0xl << 24) | (gamma0xh >>> 8)) ^
           (gamma0xh >>> 7);
        var gamma0l =
          ((gamma0xh << 31) | (gamma0xl >>> 1)) ^
          ((gamma0xh << 24) | (gamma0xl >>> 8)) ^
          ((gamma0xh << 25) | (gamma0xl >>> 7));

        // Gamma1
        var gamma1xh = w[(i-2) * 2];
        var gamma1xl = w[(i-2) * 2 + 1];
        var gamma1h =
          ((gamma1xl << 13) | (gamma1xh >>> 19)) ^
          ((gamma1xh << 3)  | (gamma1xl >>> 29)) ^
           (gamma1xh >>> 6);
        var gamma1l =
          ((gamma1xh << 13) | (gamma1xl >>> 19)) ^
          ((gamma1xl << 3)  | (gamma1xh >>> 29)) ^
          ((gamma1xh << 26) | (gamma1xl >>> 6));

        // Shortcuts
        var wr7h = w[(i-7) * 2];
        var wr7l = w[(i-7) * 2 + 1];

        var wr16h = w[(i-16) * 2];
        var wr16l = w[(i-16) * 2 + 1];

        // W(round) = gamma0 + W(round - 7) + gamma1 + W(round - 16)
        wrl = gamma0l + wr7l;
        wrh = gamma0h + wr7h + ((wrl >>> 0) < (gamma0l >>> 0) ? 1 : 0);
        wrl += gamma1l;
        wrh += gamma1h + ((wrl >>> 0) < (gamma1l >>> 0) ? 1 : 0);
        wrl += wr16l;
        wrh += wr16h + ((wrl >>> 0) < (wr16l >>> 0) ? 1 : 0);
      }

      w[i*2]     = wrh |= 0;
      w[i*2 + 1] = wrl |= 0;

      // Ch
      var chh = (eh & fh) ^ (~eh & gh);
      var chl = (el & fl) ^ (~el & gl);

      // Maj
      var majh = (ah & bh) ^ (ah & ch) ^ (bh & ch);
      var majl = (al & bl) ^ (al & cl) ^ (bl & cl);

      // Sigma0
      var sigma0h = ((al << 4) | (ah >>> 28)) ^ ((ah << 30) | (al >>> 2)) ^ ((ah << 25) | (al >>> 7));
      var sigma0l = ((ah << 4) | (al >>> 28)) ^ ((al << 30) | (ah >>> 2)) ^ ((al << 25) | (ah >>> 7));

      // Sigma1
      var sigma1h = ((el << 18) | (eh >>> 14)) ^ ((el << 14) | (eh >>> 18)) ^ ((eh << 23) | (el >>> 9));
      var sigma1l = ((eh << 18) | (el >>> 14)) ^ ((eh << 14) | (el >>> 18)) ^ ((el << 23) | (eh >>> 9));

      // K(round)
      var krh = k[i*2];
      var krl = k[i*2+1];

      // t1 = h + sigma1 + ch + K(round) + W(round)
      var t1l = hl + sigma1l;
      var t1h = hh + sigma1h + ((t1l >>> 0) < (hl >>> 0) ? 1 : 0);
      t1l += chl;
      t1h += chh + ((t1l >>> 0) < (chl >>> 0) ? 1 : 0);
      t1l += krl;
      t1h += krh + ((t1l >>> 0) < (krl >>> 0) ? 1 : 0);
      t1l = t1l + wrl|0;   // FF32..FF34 perf issue https://bugzilla.mozilla.org/show_bug.cgi?id=1054972
      t1h += wrh + ((t1l >>> 0) < (wrl >>> 0) ? 1 : 0);

      // t2 = sigma0 + maj
      var t2l = sigma0l + majl;
      var t2h = sigma0h + majh + ((t2l >>> 0) < (sigma0l >>> 0) ? 1 : 0);

      // Update working variables
      hh = gh;
      hl = gl;
      gh = fh;
      gl = fl;
      fh = eh;
      fl = el;
      el = (dl + t1l) | 0;
      eh = (dh + t1h + ((el >>> 0) < (dl >>> 0) ? 1 : 0)) | 0;
      dh = ch;
      dl = cl;
      ch = bh;
      cl = bl;
      bh = ah;
      bl = al;
      al = (t1l + t2l) | 0;
      ah = (t1h + t2h + ((al >>> 0) < (t1l >>> 0) ? 1 : 0)) | 0;
    }

    // Intermediate hash
    h0l = h[1] = (h0l + al) | 0;
    h[0] = (h0h + ah + ((h0l >>> 0) < (al >>> 0) ? 1 : 0)) | 0;
    h1l = h[3] = (h1l + bl) | 0;
    h[2] = (h1h + bh + ((h1l >>> 0) < (bl >>> 0) ? 1 : 0)) | 0;
    h2l = h[5] = (h2l + cl) | 0;
    h[4] = (h2h + ch + ((h2l >>> 0) < (cl >>> 0) ? 1 : 0)) | 0;
    h3l = h[7] = (h3l + dl) | 0;
    h[6] = (h3h + dh + ((h3l >>> 0) < (dl >>> 0) ? 1 : 0)) | 0;
    h4l = h[9] = (h4l + el) | 0;
    h[8] = (h4h + eh + ((h4l >>> 0) < (el >>> 0) ? 1 : 0)) | 0;
    h5l = h[11] = (h5l + fl) | 0;
    h[10] = (h5h + fh + ((h5l >>> 0) < (fl >>> 0) ? 1 : 0)) | 0;
    h6l = h[13] = (h6l + gl) | 0;
    h[12] = (h6h + gh + ((h6l >>> 0) < (gl >>> 0) ? 1 : 0)) | 0;
    h7l = h[15] = (h7l + hl) | 0;
    h[14] = (h7h + hh + ((h7l >>> 0) < (hl >>> 0) ? 1 : 0)) | 0;
  }
};


//// hmac.js

/** @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;
};


//// pbkdf2.js


/** @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;
};


//// sha256.js

/** @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;
  }
};

/**
 * Context for a RIPEMD-160 operation in progress.
 * @constructor
 */
sjcl.hash.ripemd160 = 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.ripemd160.hash = function (data) {
  return (new sjcl.hash.ripemd160()).update(data).finalize();
};

sjcl.hash.ripemd160.prototype = {
    /**
     * Reset the hash state.
     * @return this
     */
    reset: function () {
        this._h = _h0.slice(0);
        this._buffer = [];
        this._length = 0;
        return this;
    },

    /**
     * Reset the hash state.
     * @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");
        }
        for (i = 512+ol - ((512+ol) & 511); i <= nl; i+= 512) {
            var words = b.splice(0,16);
            for ( var w = 0; w < 16; ++w )
                words[w] = _cvt(words[w]);

            _block.call( this, words );
        }

        return this;
    },

    /**
     * Complete hashing and output the hash value.
     * @return {bitArray} The hash value, an array of 5 big-endian words.
     */
    finalize: function () {
        var b = sjcl.bitArray.concat( this._buffer, [ sjcl.bitArray.partial(1,1) ] ),
            l = ( this._length + 1 ) % 512,
            z = ( l > 448 ? 512 : 448 ) - l % 448,
            zp = z % 32;

        if ( zp > 0 )
            b = sjcl.bitArray.concat( b, [ sjcl.bitArray.partial(zp,0) ] );
        for ( ; z >= 32; z -= 32 )
            b.push(0);

        b.push( _cvt( this._length | 0 ) );
        b.push( _cvt( Math.floor(this._length / 0x100000000) ) );

        while ( b.length ) {
            var words = b.splice(0,16);
            for ( var w = 0; w < 16; ++w )
                words[w] = _cvt(words[w]);

            _block.call( this, words );
        }

        var h = this._h;
        this.reset();

        for ( var w = 0; w < 5; ++w )
            h[w] = _cvt(h[w]);

        return h;
    }
};

var _h0 = [ 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0 ];

var _k1 = [ 0x00000000, 0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xa953fd4e ];
var _k2 = [ 0x50a28be6, 0x5c4dd124, 0x6d703ef3, 0x7a6d76e9, 0x00000000 ];
for ( var i = 4; i >= 0; --i ) {
    for ( var j = 1; j < 16; ++j ) {
        _k1.splice(i,0,_k1[i]);
        _k2.splice(i,0,_k2[i]);
    }
}

var _r1 = [  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
             7,  4, 13,  1, 10,  6, 15,  3, 12,  0,  9,  5,  2, 14, 11,  8,
             3, 10, 14,  4,  9, 15,  8,  1,  2,  7,  0,  6, 13, 11,  5, 12,
             1,  9, 11, 10,  0,  8, 12,  4, 13,  3,  7, 15, 14,  5,  6,  2,
             4,  0,  5,  9,  7, 12,  2, 10, 14,  1,  3,  8, 11,  6, 15, 13 ];
var _r2 = [  5, 14,  7,  0,  9,  2, 11,  4, 13,  6, 15,  8,  1, 10,  3, 12,
             6, 11,  3,  7,  0, 13,  5, 10, 14, 15,  8, 12,  4,  9,  1,  2,
            15,  5,  1,  3,  7, 14,  6,  9, 11,  8, 12,  2, 10,  0,  4, 13,
             8,  6,  4,  1,  3, 11, 15,  0,  5, 12,  2, 13,  9,  7, 10, 14,
            12, 15, 10,  4,  1,  5,  8,  7,  6,  2, 13, 14,  0,  3,  9, 11 ];

var _s1 = [ 11, 14, 15, 12,  5,  8,  7,  9, 11, 13, 14, 15,  6,  7,  9,  8,
             7,  6,  8, 13, 11,  9,  7, 15,  7, 12, 15,  9, 11,  7, 13, 12,
            11, 13,  6,  7, 14,  9, 13, 15, 14,  8, 13,  6,  5, 12,  7,  5,
            11, 12, 14, 15, 14, 15,  9,  8,  9, 14,  5,  6,  8,  6,  5, 12,
             9, 15,  5, 11,  6,  8, 13, 12,  5, 12, 13, 14, 11,  8,  5,  6 ];
var _s2 = [  8,  9,  9, 11, 13, 15, 15,  5,  7,  7,  8, 11, 14, 14, 12,  6,
             9, 13, 15,  7, 12,  8,  9, 11,  7,  7, 12,  7,  6, 15, 13, 11,
             9,  7, 15, 11,  8,  6,  6, 14, 12, 13,  5, 14, 13, 13,  7,  5,
            15,  5,  8, 11, 14, 14,  6, 14,  6,  9, 12,  9, 12,  5, 15,  8,
             8,  5, 12,  9, 12,  5, 14,  6,  8, 13,  6,  5, 15, 13, 11, 11 ];

function _f0(x,y,z) {
    return x ^ y ^ z;
}

function _f1(x,y,z) {
    return (x & y) | (~x & z);
}

function _f2(x,y,z) {
    return (x | ~y) ^ z;
}

function _f3(x,y,z) {
    return (x & z) | (y & ~z);
}

function _f4(x,y,z) {
    return x ^ (y | ~z);
}

function _rol(n,l) {
    return (n << l) | (n >>> (32-l));
}

function _cvt(n) {
    return ( (n & 0xff <<  0) <<  24 )
         | ( (n & 0xff <<  8) <<   8 )
         | ( (n & 0xff << 16) >>>  8 )
         | ( (n & 0xff << 24) >>> 24 );
}

function _block(X) {
    var A1 = this._h[0], B1 = this._h[1], C1 = this._h[2], D1 = this._h[3], E1 = this._h[4],
        A2 = this._h[0], B2 = this._h[1], C2 = this._h[2], D2 = this._h[3], E2 = this._h[4];

    var j = 0, T;

    for ( ; j < 16; ++j ) {
        T = _rol( A1 + _f0(B1,C1,D1) + X[_r1[j]] + _k1[j], _s1[j] ) + E1;
        A1 = E1; E1 = D1; D1 = _rol(C1,10); C1 = B1; B1 = T;
        T = _rol( A2 + _f4(B2,C2,D2) + X[_r2[j]] + _k2[j], _s2[j] ) + E2;
        A2 = E2; E2 = D2; D2 = _rol(C2,10); C2 = B2; B2 = T; }
    for ( ; j < 32; ++j ) {
        T = _rol( A1 + _f1(B1,C1,D1) + X[_r1[j]] + _k1[j], _s1[j] ) + E1;
        A1 = E1; E1 = D1; D1 = _rol(C1,10); C1 = B1; B1 = T;
        T = _rol( A2 + _f3(B2,C2,D2) + X[_r2[j]] + _k2[j], _s2[j] ) + E2;
        A2 = E2; E2 = D2; D2 = _rol(C2,10); C2 = B2; B2 = T; }
    for ( ; j < 48; ++j ) {
        T = _rol( A1 + _f2(B1,C1,D1) + X[_r1[j]] + _k1[j], _s1[j] ) + E1;
        A1 = E1; E1 = D1; D1 = _rol(C1,10); C1 = B1; B1 = T;
        T = _rol( A2 + _f2(B2,C2,D2) + X[_r2[j]] + _k2[j], _s2[j] ) + E2;
        A2 = E2; E2 = D2; D2 = _rol(C2,10); C2 = B2; B2 = T; }
    for ( ; j < 64; ++j ) {
        T = _rol( A1 + _f3(B1,C1,D1) + X[_r1[j]] + _k1[j], _s1[j] ) + E1;
        A1 = E1; E1 = D1; D1 = _rol(C1,10); C1 = B1; B1 = T;
        T = _rol( A2 + _f1(B2,C2,D2) + X[_r2[j]] + _k2[j], _s2[j] ) + E2;
        A2 = E2; E2 = D2; D2 = _rol(C2,10); C2 = B2; B2 = T; }
    for ( ; j < 80; ++j ) {
        T = _rol( A1 + _f4(B1,C1,D1) + X[_r1[j]] + _k1[j], _s1[j] ) + E1;
        A1 = E1; E1 = D1; D1 = _rol(C1,10); C1 = B1; B1 = T;
        T = _rol( A2 + _f0(B2,C2,D2) + X[_r2[j]] + _k2[j], _s2[j] ) + E2;
        A2 = E2; E2 = D2; D2 = _rol(C2,10); C2 = B2; B2 = T; }

    T = this._h[1] + C1 + D2;
    this._h[1] = this._h[2] + D1 + E2;
    this._h[2] = this._h[3] + E1 + A2;
    this._h[3] = this._h[4] + A1 + B2;
    this._h[4] = this._h[0] + B1 + C2;
    this._h[0] = T;
}

/** @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;
  }
};