Start passing cipher from EncryptedCookieJar since we use it to determine key length

1 files changed, 7 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/message_encryptor.rb b/activesupport/lib/active_support/message_encryptor.rb
index ab8b2f8ded..7b33dc3481 100644
--- a/activesupport/lib/active_support/message_encryptor.rb
+++ b/activesupport/lib/active_support/message_encryptor.rb
@@ -19,6 +19,8 @@ module ActiveSupport
   #   encrypted_data = crypt.encrypt_and_sign('my secret data')              # => "NlFBTTMwOUV5UlA1QlNEN2xkY2d6eThYWWh..."
   #   crypt.decrypt_and_verify(encrypted_data)                               # => "my secret data"
   class MessageEncryptor
+    DEFAULT_CIPHER = "aes-256-cbc"
+
     module NullSerializer #:nodoc:
       def self.load(value)
         value
@@ -77,6 +79,11 @@ module ActiveSupport
       _decrypt(verifier.verify(value))
     end
 
+    # Given a cipher, returns the key length of the cipher to help generate the key of desired size
+    def self.key_len(cipher = DEFAULT_CIPHER)
+      OpenSSL::Cipher.new(cipher).key_len
+    end
+
     private
 
       def _encrypt(value)