[design question] Symmetric cipher interface.

[Martin <eden_martin_fuhrspam@...>]

In continuation of Dirk's Laurie proposal for standard interface for
common things...

How do you see generic interface for symmetric encryption/decryption?

Usually you can process input stream by parts (in case you wish to
encrypt 50GiB file which unlikely fit into string). Do you prefer
some functions encrypt()/decrypt() which returns output and inner
state, or object that holds inner state itself?

(There are a plenty of simple ciphers (Tea, Salsa, Spec) and I'd
wish to unite their implementations under common interface.)

-- Martin