From: roob noob <lists@...>
Date: 2012-05-17T03:16:31+09:00
Subject: what is going wrong here?

Notice the initialization of both classes in each of the examples, if
the instance variable is in initialization or in the called method is
the only thing changing between these examples.

I don't understand why I can't begin both classes with the
initialization
set to what I want it to be, I would think that the initialization value
would be consistent for the objects entire life but it only works for
the first pass, the second time through it doesn't work. The only way to
fix this is to not have the respective instance variable set in
initialization with either of the two classes. What is going wrong here?
I like to set variables during initialization but it clearly doesn't
work how I would hope, I would like to understand what is going wrong
because even though I can get it to work I don't see why it doesn't work
in some cases.

Maybe it has to do with my poor use of instance variables :/, if this is
the case I would still like to know what is going on so I can find a way
to work around it

when I say it doesn't work I mean the output is not correct, it gives me
random looking output the second time even though it should give the
plaintext.

###############This way doesn't work##################


class EncryptionBackend
require 'openssl'

  def initialize
    @cipher = OpenSSL::Cipher::Cipher.new("AES-256-CTR")
  end

  def encrypt(key, plaintext)
  puts plaintext
    @cipher.encrypt
    @cipher.key = key
    ciphertext = @cipher.update(plaintext)
    ciphertext << @cipher.final
    @cipher.reset
    puts ciphertext
    @ciphertext = ciphertext


  end
end

class EncryptMessage
require 'openssl'

  def initialize
    @crypto = EncryptionBackend.new
  end

  def twice
    @message = "whatever"
    encrypt_message
    encrypt_message

  end

  def encrypt_message
    @sha256 = OpenSSL::Digest::SHA256.new
    key = @sha256.digest("whatever")
    @message = @crypto.encrypt(key, @message)
  end
end

message_encrypt = EncryptMessage.new
message_encrypt.twice

###############This way works###################

class EncryptionBackend
require 'openssl'

  def initialize
    @cipher = OpenSSL::Cipher::Cipher.new("AES-256-CTR")
  end

  def encrypt(key, plaintext)
  puts plaintext
    @cipher.encrypt
    @cipher.key = key
    ciphertext = @cipher.update(plaintext)
    ciphertext << @cipher.final
    @cipher.reset
    puts ciphertext
    @ciphertext = ciphertext


  end
end

class EncryptMessage
require 'openssl'

  def initialize
    #nothing
  end

  def twice
    @message = "whatever"
    encrypt_message
    encrypt_message

  end

  def encrypt_message
    @crypto = EncryptionBackend.new
    @sha256 = OpenSSL::Digest::SHA256.new
    key = @sha256.digest("whatever")
    @message = @crypto.encrypt(key, @message)
  end
end

message_encrypt = EncryptMessage.new
message_encrypt.twice


###############this way works though##################


class EncryptionBackend
require 'openssl'

  def initialize
    #nothing
  end

  def encrypt(key, plaintext)
  @cipher = OpenSSL::Cipher::Cipher.new("AES-256-CTR")
  puts plaintext
    @cipher.encrypt
    @cipher.key = key
    ciphertext = @cipher.update(plaintext)
    ciphertext << @cipher.final
    @cipher.reset
    puts ciphertext
    @ciphertext = ciphertext


  end
end

class EncryptMessage
require 'openssl'

  def initialize
    @crypto = EncryptionBackend.new
  end

  def twice
    @message = "whatever"
    encrypt_message
    encrypt_message

  end

  def encrypt_message
    @sha256 = OpenSSL::Digest::SHA256.new
    key = @sha256.digest("whatever")
    @message = @crypto.encrypt(key, @message)
  end
end

message_encrypt = EncryptMessage.new
message_encrypt.twice

################This way also works#######################


class EncryptionBackend
require 'openssl'

  def initialize
    @cipher = OpenSSL::Cipher::Cipher.new("AES-256-CTR")
  end

  def encrypt(key, plaintext)
  puts plaintext
    @cipher.encrypt
    @cipher.key = key
    ciphertext = @cipher.update(plaintext)
    ciphertext << @cipher.final
    @cipher.reset
    puts ciphertext
    @ciphertext = ciphertext


  end
end

class EncryptMessage
require 'openssl'

  def initialize
    ##nothing
  end

  def twice
    @message = "whatever"
    encrypt_message
    encrypt_message

  end

  def encrypt_message
    @crypto = EncryptionBackend.new
    @sha256 = OpenSSL::Digest::SHA256.new
    key = @sha256.digest("whatever")
    @message = @crypto.encrypt(key, @message)
  end
end

message_encrypt = EncryptMessage.new
message_encrypt.twice

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