Have it take in a cipher init function as an argument.
Remove the confusing `newCipher` method that matched legacy behavior
and returns a Base64Cipher(CFBCipher) -- instead explicitly ask for
that in the uses.
All Encrypt/Decrypt Cipher implementations will now take
and return []byte to set up usage in future binary compatible
encoding schemes to fix issues with bloat encrypting to strings
(which requires base64ing adding 33% size)
* Add support for preferred username.
* Add missing TOC entries.
* Add note about preferred_username support.
* Adjust tests.
* Check on not implemented error for GetPreferredUsername() call.
Co-authored-by: Felix Fontein <felix@fontein.de>
Co-authored-by: Joel Speed <Joel.speed@hotmail.co.uk>
