MySQL AES Encryption in Ruby

I was asked to find a way to encrypt strings in Ruby that would be compatible with MySQL's AES_ENCRYPT and AES_DECRYPT functions. I found several solutions online, but none of them worked the way I expected. After cobbling together several examples, I finally came up with a solution that proved to be compatible with the MySQL version. This was written for use with Ruby 2.3.5.

	require 'openssl'
	# This module provides AES encryption compatible with MySQL AES_ENCRYPT
	# and AES_DECRYPT functions.
	module MySQLEncryption
	# Takes an unencrypted text string, encrypts it with the password,
	# and encodes the results to a hexadecimal string
	def self.mysql_encrypt(unencrypted_text, password)
	encrypt(unencrypted_text, mysql_key(password))
	end
	# Takes an encrypted, hex-encoded text string
	# and decrypts it with the password
	def self.mysql_decrypt(encrypted_hex, password)
	decrypt(encrypted_hex, mysql_key(password))
	end
	# Encode a binary value to hexadecimal
	def self.bin_to_hex(binary)
	binary.unpack('H*').first
	end
	# Decode a hex value into a binary
	def self.hex_to_bin(hex)
	hex.scan(/../).map {|digit| digit.hex}.pack('c*')
	end
	protected
	def self.aes(method, mysql_key, text)
	aes = OpenSSL::Cipher::Cipher.new('aes-128-ecb')
	aes.send(method)
	aes.key = mysql_key
	aes.update(text) << aes.final
	end
	def self.encrypt(unencrypted_text, mysql_key)
	bin_to_hex(aes(:encrypt, mysql_key, unencrypted_text))
	end
	def self.decrypt(encrypted_hex, mysql_key)
	aes(:decrypt, mysql_key, hex_to_bin(encrypted_hex))
	end
	def self.mysql_key(key)
	final_key = "\0" * 16
	key.length.times do |i|
	final_key[i % 16] = (final_key[i % 16].ord ^ key[i].ord).chr
	end
	final_key
	end
	end

view raw my_sql_encryption.rb hosted with ❤ by GitHub

This module can be used as follows:

	require 'my_sql_encryption'
	text = 'Sensitive data'
	encrypted = MySQLEncryption.mysql_encrypt(text, @password)
	decrypted = MySQLEncryption.mysql_decrypt(encrypted, @password)
	log.info("Encrypted: #{encrypted}")
	log.info("Decrypted: #{decrypted}")
	expect(decrypted).to eq(text)

view raw my_sql_encryption_example.rb hosted with ❤ by GitHub