Several of us RIPEM developers are considering how to extend
RIPEM so it can encrypt non-text messages, and compress those
messages. Other modifications of the plaintext are conceivable.
The principal question is how we should indicate the type of
file in the PEM headers.
Our current thinking is to implement a PEM header like:
Content-Type: Type[/Subtype][,Modifier[/Submodifier]]*
Examples:
Content-Type: Binary
Content-Type: Binary/MacBinary,Compressed/ZIP
Content-Type: Binary,Compressed/compress
or some such.
If an implementation of RIPEM did not understand the subtype, it would do
the best it could. E.g., on a PC, Binary/MacBinary would simply
be decoded as a byte stream, and the user would have to make
sense of it. If [de]compression weren't implemented in an implementation,
upon decryption, RIPEM would just emit the compressed message.
Our goal is to stay as PEM-compliant and MIME-compliant
as possible without taking on the task of implementing
full MIME. (Implementing full PEM is an eventual goal,
but we're making no commitments.)
We don't want to go off and do something unique and
non-interoperable, but we do want to implement something
in the not-too-distant future.
What are your recommendations for syntax?
Mark R.