mcrypt_aes_cbc does not substr longer keys like mcrypt_rij_256 did

Why would you want to do this silently? Incorrect key sizes should imo fail hard.

My main concern with this is that it can easily hide a mistake by the user. For example, if you create a random 256-bit key and base64-encode it, it will be 44 characters long. If you forget to check the box to indicate to Encrypt that it's base64-encoded, with this patch the key will be truncated to 32 characters, substantially reducing the quality of the key without giving any indication, since encryption and decryption will work fine.

@SpadXIII, please explain the use case for allowing longer keys.

My guess is that this is for backwards compatibility ...

@SpadXIII, if you are using $conf['encrypt_drupal_variable_key'] in your settings.php to set a key, you could perform the substr() there; if needed.

Closing this as won't fix. Reopen it to continue the discussion.