[9fans] passtokey question

["Roman V. Shaposhnick" <vugluskr@unicorn.math.spbu.ru>]

I'm quite new to the world of auth related algorithms, so my question
might be a FAQish one, but nevertheless, here it is anyway. Why
passtokey works the way it does. I suppose there were some security
related considerations, by I can't seem to grasp, why, for example,
this is being done:

    for(i = 0; i < DESKEYLEN; i++)
	key[i] = (t[i] >> i) + (t[i+1] << (8 - (i+1)));

where you kinda shuffle bytes around, but why ? Just to stuff
8 bytes from t into 7 bytes of key ?

On the similar note, why did you chose to re-encode parts of t with
a previous key, and not some other way of stuffing long passwords
into 7bytes long DES key ?

Thanks,
Roman.