Nodejs Acquisition Time Plus Mobile Phone Identification 32 bit Identification Implementation Code

The specific code is as follows:

var crypto = require("crypto");
function randomlogn(num){
 var n = num.split('');
 var m = [];
 for(var i=0;i<16;i++){
  m[i] = n[Math.floor(Math.random()*17)];
 }
 return u = m.join("");
}
// Random number 
function md5(text) {
 return crypto.createHash('md5').update(text).digest('hex');
};
/**
 *  Make   Use   Randomly generated 1 Identifiers 
 * @param  : string [time] 13 Time stamp of bit  string data  Identifier of mobile phone 
 * @return: string data 32 A string of bits  
*/
exports.randomWord = function(time, data) { //  Time  13  Identification  15  Bit    Random  4 Number of digits 
 var g,o,h;
 g = md5(data).substr(16, 32);
 o = randomlogn(g);
 h = randomlogn(o);
 if (!time) {
  time = new Date().getTime()
 };
 var str = "",
  arr = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'];
 //  Random generation 
 for(var i = 0; i < 4; i++) {
  pos = Math.round(Math.random() * (arr.length - 1));
  str += arr[pos];
 }
 return time + h + str
}