Minimal symmetric crypto support for vim

[Jason Holt]

On Sun, 25 May 2003, Werner Koch wrote:
> 
> It could be done with not too much code if you don't want to be able
> to decode all OpenPGP messages.  If you use full 4 byte packet length
> headers and no compression you should be able to do everything
> statically.  You need the string-to-key mangling code (S2K), a SHA-1
> implementation and AES.

That doesn't sound impossible.  What's the anatomy of such a message?  
Something like this?

0x4, AES, S2K
(Symmetric-Key Encrypted Session Key Packet)

0x1, Literal Data Packet
(Sym. Encrypted Integrity Protected Data Packet)

20 bytes of SHA-1 on (start-of-plaintext ... start of MDC packet header)
(Modification Detection Code Packet)

Can anyone expand that off the top of their head?  

					-J