Class: ActiveSupport::MessageEncryptor

Inherits:
Object
  • Object
show all
Defined in:
lib/active_support/message_encryptor.rb

Overview

MessageEncryptor is a simple way to encrypt values which get stored somewhere you don’t trust.

The cipher text and initialization vector are base64 encoded and returned to you.

This can be used in situations similar to the MessageVerifier, but where you don’t want users to be able to determine the value of the payload.

Defined Under Namespace

Classes: InvalidMessage

Constant Summary collapse

OpenSSLCipherError = 
OpenSSL::Cipher.const_defined?(:CipherError) ? OpenSSL::Cipher::CipherError : OpenSSL::CipherError

Instance Method Summary collapse

Constructor Details

#initialize(secret, cipher = 'aes-256-cbc') ⇒ MessageEncryptor

Returns a new instance of MessageEncryptor.



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# File 'lib/active_support/message_encryptor.rb', line 15

def initialize(secret, cipher = 'aes-256-cbc')
  @secret = secret
  @cipher = cipher
end

Instance Method Details

#decrypt(encrypted_message) ⇒ Object 



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# File 'lib/active_support/message_encryptor.rb', line 35

def decrypt(encrypted_message)
  cipher = new_cipher
  encrypted_data, iv = encrypted_message.split("--").map {|v| ActiveSupport::Base64.decode64(v)}
  
  cipher.decrypt
  cipher.key = @secret
  cipher.iv  = iv

  decrypted_data = cipher.update(encrypted_data)
  decrypted_data << cipher.final
  
  Marshal.load(decrypted_data)
rescue OpenSSLCipherError, TypeError
  raise InvalidMessage
end

#decrypt_and_verify(value) ⇒ Object 



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# File 'lib/active_support/message_encryptor.rb', line 55

def decrypt_and_verify(value)
  decrypt(verifier.verify(value))
end

#encrypt(value) ⇒ Object 



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# File 'lib/active_support/message_encryptor.rb', line 20

def encrypt(value)
  cipher = new_cipher
  # Rely on OpenSSL for the initialization vector
  iv = cipher.random_iv
  
  cipher.encrypt 
  cipher.key = @secret
  cipher.iv  = iv
  
  encrypted_data = cipher.update(Marshal.dump(value)) 
  encrypted_data << cipher.final

  [encrypted_data, iv].map {|v| ActiveSupport::Base64.encode64s(v)}.join("--")
end

#encrypt_and_sign(value) ⇒ Object 



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# File 'lib/active_support/message_encryptor.rb', line 51

def encrypt_and_sign(value)
  verifier.generate(encrypt(value))
end