Crypto

Crypto?

• Crypto is built-in cryptographic module for node
• Crypto can be used for implementing cryptographic protocols, such as:
  • TLS
  • https
• Crypto offers functions for calculating hashes, using ciphers and more 

Hashing

• Hashing is one way data encryption method
• A hash is (in theory) impossible to invert
• Hashes are commonly used for storing passwords in databases
  • Storing just hash of the password is not considered secure
  • Password should be hashed with a salt
    • Salt is a random string that is included in password before hashing
    • Salt should be unique for each stored password

Creating hash using crypto

var crypto = require("crypto");

// Hash in hex format
crypto.createHash("sha1").update("Lorem ipsum!").digest("hex");

// Output: 8a52c69607956f0a186fa4efc75e6f66db1568b3

Supported hashing algorithms:

• md5
• sha1
• sha512
• .. and much more (use crypto.getHashes() to check available algorithms) 

Ciphers

• Ciphers allow messages to be encrypted with a password
• Ciphers look similar to hashes, but they are reversible if recipient knows the password for the cipher

Cipher example

var crypto = require('crypto')
var pwd = 'password'
var text = 'Salainen viesti!'
var cipher = crypto.createCipher('aes256', pwd)
var decipher = crypto.createDecipher('aes256', pwd);
  
var salattu = cipher.update(text, 'utf8', 'hex');
salattu += cipher.final('hex')
 
var salaamaton = decipher.update(salattu, 'hex', 'utf8');
salaamaton += decipher.final('utf8');
 
console.log('salattu :', salattu); 
// fcf5304a2dc5763509f1de77ab0a457b4c9879ec34c3e5828dcacd91145b8cc4
console.log('salaamaton :', salaamaton); 
// Salainen viesti!