Dropbear calling my own command-line parser than /bin/sh.

[Matt Johnston]

On Tue, Jul 18, 2006 at 06:53:18PM -0700, Prasad wrote:
> The only problem now i have is that the entire process is really slow
> until i get the login. I takes about 90 secs for me to get the shell.
> (With or with-out the changes for my own interpreter). After i get
> login everything is pretty fast. The size of the SSH key is 1024 bit.
> (512 bytes reduces the time by about 60 secs).
> 
> Doing a quick check, majoriy of the time taken was in mp_exptmod()
> routine with each call takes around 25 secs. I am running my
> processor(microblaze) at about 60mhz with hardware multipler, divider
> enabled.
> 
> >From your knowledge, Is there any way to accelerate this in software
> or the only way to increase this is by hardware-acceleration?

Using a DSS hostkey might be faster than RSA, you could try
that. I assume you're already compling with -O2 (or whatever
works for your platform) - that can make a big difference.
Aside from that, I'm not really sure. Looking at a faster
math library (or optimising LibTomCrypt) could be an option.
It looks as if TomsFastMath might be a fairly easy
replacement, though I'm not sure how portable or mature that
is.

Cheers,
Matt