Pure python crypto

[Paul Rubin]

Michael Gilfix <mgilfix at eecs.tufts.edu> writes:
>   The nice thing about blowfish is its simplicity. I started thinking
> about implementing DES and 3DES though and its ugly. 

Blowfish isn't so simple to implement in Python, plus the key setup
is awfully slow.

>   I was thinking that it might be nice to have an 'ssh' module or
> 'sftp' module. Specifically, I wanted sftp for an application and
> couldn't find any such modules. For portability reasons, it might
> be nice to have a pure python module, however, it would require
> some tweaking I'm sure.

I think RC4 coded in Python would run much faster than Blowfish coded
in Python.  SSH can use RC4.  I don't know what SFTP is.

FWIW, I coded RC4 in Python a while back and if I remember correctly,
got about 100k/sec throughput on a P3-750.  That's sort of marginal
for (say) sftp over ADSL.  Using the SHA-OFB hack that I described,
I got about 400-500k/sec.