How to encrypt and decrypt a number using same key? - node.js

Question

I need a way to encrypt a number (say 3423234234) using a secret key, which can also be decrypted using that same key.
const encrypted = encrypt(number, key)
const decrypted = decrypt(encrypted, key)
I tried CryptoJS using AES, DES, Rabbit and RC4 algorithms, but it gives me a long encrypted value with special characters.
I want some encrypted value like MongoDB's ObjectId (which contains only alphanumeric characters like 1575866cab3f22f0c8510451f293f405, and should not exceed 20 or 40 characters).

Answer 1

I figured out a way.
const decrypt = function (num) {
const base = "tGVwFAPiJqh3maNHdZfby9eIQXcr2zvgD57YMn8KWCxkSUujpB10sL6oRTl4OE"
num = num.toString()
let lastChar, baseConverted = 0, index=0;
while(num !== ''){
lastChar = num.slice(-1);
baseConverted += base.indexOf(lastChar) * Math.pow(62,index);
index++;
num = num.slice(0, num.length-1);
}
return baseConverted;
};
const encrypt = function (num) {
const base = "tGVwFAPiJqh3maNHdZfby9eIQXcr2zvgD57YMn8KWCxkSUujpB10sL6oRTl4OE"
// console.log(base.length)
let mod, baseConverted = '';
while(num){
mod = num%62;
baseConverted = base.slice(mod, mod+1)+baseConverted;
num = Math.floor(num/62);
}
return baseConverted;
};
module.exports = {
encrypt,
decrypt
}
The reason I wanted it because I want to encrypt all the id's of a resource before sharing it with client.
It will decrypt the keys when request is received.