encrypt.js

// Generated by CoffeeScript 1.3.3
(function() {
  var crypto, int32Max, merge_sort;

  crypto = require("crypto");

  merge_sort = require("./merge_sort").merge_sort;

  int32Max = Math.pow(2, 32);

  exports.getTable = function(key) {
    var ah, al, decrypt_table, hash, i, md5sum, table;
    table = new Array(256);
    decrypt_table = new Array(256);
    md5sum = crypto.createHash("md5");
    md5sum.update(key);
    hash = new Buffer(md5sum.digest(), "binary");
    al = hash.readUInt32LE(0);
    ah = hash.readUInt32LE(4);
    i = 0;
    while (i < 256) {
      table[i] = i;
      i++;
    }
    i = 1;
    while (i < 1024) {
      table = merge_sort(table, function(x, y) {
        return ((ah % (x + i)) * int32Max + al) % (x + i) - ((ah % (y + i)) * int32Max + al) % (y + i);
      });
      i++;
    }
    i = 0;
    while (i < 256) {
      decrypt_table[table[i]] = i;
      ++i;
    }
    return [table, decrypt_table];
  };

  exports.encrypt = function(table, buf) {
    var i;
    i = 0;
    while (i < buf.length) {
      buf[i] = table[buf[i]];
      i++;
    }
    return buf;
  };

}).call(this);