Topic: Simplify encryption

I have this code for encrypting data. How can I simply this and make this as simple as possible? Still with an easy encryption that doesn't make too long strings. And do I need all three requires?


require 'openssl'
require 'digest/sha2'
require 'cgi'

module Crypto
 
  def self.encrypt(plain_text)
    
    cgi = CGI.new("html3")
    passo = "my_password"
    
    begin
      c = OpenSSL::Cipher::Cipher.new("aes-128-cbc")
      c.encrypt
      c.key = key = Digest::SHA2.digest(passo)
      e = c.update(plain_text)
      e << c.final
      e = Base64.b64encode(e)
    rescue
      return
    end
    
     return e
    
  end
 
  def self.decrypt(cstring)
    
    cgi = CGI.new("html3")
    passo = "my_password"
    
    begin
      etext = Base64.decode64(cstring)
      c = OpenSSL::Cipher::Cipher.new("aes-128-cbc")
      c.decrypt
      c.key = key = Digest::SHA2.digest(passo)
      d = c.update(etext)
      d << c.final
    rescue
      return
    end
      
    return d
    
  end
   
 
end