Ruby AES encryption test with lib openssl

aes_test.rb

#!/usr/bin/env ruby
# encoding: UTF-8

require 'rubygems'
begin
require 'bundler/setup'
rescue LoadError
end
require 'digest/sha1'
require 'openssl'
require 'base64'

class AES
  Type = "AES-256-CBC"

  def initialize(pass, cipher_type=Type)
    @aes = ::OpenSSL::Cipher::Cipher.new(cipher_type)
    @aes.padding = 1
    #NOTE: a2*32 is for 256bit AES, change to 16 for 128...
    @key = Digest::SHA1.hexdigest(pass).unpack('a2'*32).map{|x|x.hex}.pack('c'*32)
    #@key = Digest::SHA256.digest(pass)
    @password = pass
  end

  def encrypt(data)
    @aes.encrypt
    @aes.key = @key
    @aes.update(data) + @aes.final
  end
  
  def decrypt(data)
    @aes.decrypt
    @aes.key = @key
    @aes.update(data) + @aes.final
  rescue OpenSSL::Cipher::CipherError
    raise PasswordInvalid, "Password incorrect!"
  end

  class PasswordInvalid < Exception
    def initialize(s); s; end
  end
end

pass = "test"
aes = AES.new(pass)
plain = "hello world"
puts "plain: #{plain.inspect}"
encstr = aes.encrypt(plain)

puts "encrypted: #{encstr.inspect}"

aes = AES.new(pass)
begin
  decrypted = aes.decrypt(encstr)
  puts "decrypted: #{decrypted.inspect}"
rescue AES::PasswordInvalid
  puts "ERROR: password is invalid"
rescue NoMethodError
  puts "ERROR: encrypted data was invalid"
end