AES encryption showcase using OpenSSL in Ruby

aes_decrypt.rb

require 'openssl'

ALGORITHM = 'AES-256-CBC'

puts 'Enter key to decrypt with (in hexadecimal):'
hex_key = gets.chomp

puts 'Enter message to decrypt (in hexadecimal):'
hex_message = gets.chomp

cipher = OpenSSL::Cipher.new(ALGORITHM)

key = [hex_key].pack('H*')
message = [hex_message].pack('H*')

cipher.decrypt
cipher.key = key

message = cipher.update(message)
message << cipher.final

puts "Decrypted message: #{message}"

aes_encrypt.rb

require 'openssl'

ALGORITHM = 'AES-256-CBC'

puts 'Enter message to encrypt:'
message = gets.chomp

cipher = OpenSSL::Cipher.new(ALGORITHM)

key = cipher.random_key
hex_key = key.unpack('H*').first

puts "Randomly generated key in hexadecimal: #{hex_key}"

cipher.encrypt
cipher.key = key

encrypted_message = cipher.update(message)
encrypted_message << cipher.final

hex_encrypted_message = encrypted_message.unpack('H*').first

puts "Encrypted message in hexadecimal: #{hex_encrypted_message}"