id-converter-aes-256-gcm.rb

require 'openssl'

KEY = '1'*32
IV = '1'*12
ALG = 'aes-256-gcm'

def bin2hex(s)
  s.unpack('H*').first
end

def hex2bin(s)
  s.scan(/../).map { |x| x.hex }.pack('c*')
end

def encrypt(plaintext)
  cipher = OpenSSL::Cipher.new(ALG)
  cipher.encrypt
  cipher.key = KEY
  cipher.iv = IV
  ciphertext = cipher.update(plaintext)
  bin2hex(ciphertext)
end

def decrypt(ciphertext)
  decipher = OpenSSL::Cipher.new(ALG)
  decipher.decrypt
  decipher.key = KEY
  decipher.iv = IV
  plaintext = decipher.update(hex2bin(ciphertext))
end

puts encrypt "00000001"         # => 4666a782147f1450
puts encrypt "00000002"         # => 4666a782147f1453
puts encrypt "00000003"         # => 4666a782147f1452
puts decrypt encrypt "00000001" # => 00000001
puts decrypt encrypt "00000002" # => 00000002
puts decrypt encrypt "00000003" # => 00000003