Ryan.Russell at SYBASE.COM
Thu Jan 20 13:48:07 EST 2000
>Has Microsoft increased the strength of PPTP's crypto? A network
>engineer friend of mine asked if the encryption has been raised to 128
>bits, and I had no answer as I've never seriously considered PPTP.
>Has this beast been strengthened the process that used a user-supplied
>password at the client to derive the MD4 hash?
Present pre-W2K implementation still derives the crypto strength from
the user password. So no, you're not getting a good 128 bits worth.
MS fixed some protocol issues, like using the same key in 2 directions,
>I gather MS raised the encryption level that will ship with Windows 2000
>to 128 bits, so does this mean PPTP gets bumped a notch too? I'd thought
>it was going away in favor of IPSec.
They've made some significant enhancements in W2K, including adding
L2TP and IPSec, I believe. I haven't read any analysis of those implementations
along the lines of the ones done for PPTP yet. One has to assume (and I
think we just had a thread on this) that the IPSec implementation can
do manually shared secrets, so if you're any good at managing passwords,
you can get your full strength.
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