Source: codecHex.js

/** @fileOverview Bit array codec implementations.
 *
 * @author Emily Stark
 * @author Mike Hamburg
 * @author Dan Boneh
 */

/**
 * Hexadecimal
 * @namespace
 */
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);
  }
};