Subject: [eap] HELP !!! EAP-TLS MPPE Key generation

From: Vijay Govindarajulu <[email-masked]>
Date: Mon, 16 Aug 2004 04:36:51 -0700

Hi,

I've gone through the free radius code to see how the MPPE keys are
generated and sent.

I have seen the code in 

 -rlm_eap_tls/mppe_keys.c

- lib/radius.c

and also debugged the freeradius and know exactly how does this happen.

I'm following the same in my implementation, viz.

1) generate 64 bytes using

PRF(master key,"client EAP encryption",client Rand , server Rand);

2) first 32 bytes is the unencrypted value  for "MPPE-Recv-Key"

3) last 32 bytes is the unencrypted value for "MPPE-Send-Key"

4) I do the encryption on these values as described in RFC 2548 section2.4.2
and 2.4.3

However I'm unable to connect to the net after sending the EAP-SUCCESS.

I know that my master key ,client random and server random are right because

these were used during client handshake finished message verification and
also

for making the server handshake finished message.

Therefore the output of (1) should be ok .

Could you give me pointers on possible points of failure?

Looking forward for your response

Thanks and Regards

Vijay Kumar Govindarajulu

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