I am trying to get the MS-MPPE-Send-key and MS-MPPE-Recv-key from the MS-CHAPv2 challenge material. I am able to follow the RFCs 2548 3078 and 3079 to the step of getting the GetNewKeyFromSHA() it is 16 bytes long.
I can use the key to encrypt data as the example in 3079. The problem is that I am not sure what should I do to get the session keys used in the RFC 2548 to get MS-MPPE-Send-key and MS-MPPE-Recv-key fields from there.
I have an example of freeradius and the session key is converted from 16 bytes long to 32 bytes long before the construction of the string stated in RFC 2548.
I have tried to encrypt with RC4 the session keys after GetNewKeyFromSHA() but it is not working for me. If someone could explain a bit in detail this intermediate step it would be nice!
Edit: I also have tried to make the encryption in 2548 twice but still no results, I am now digging into the freeRADIUS source code but it is not easy to follow after getting the master key from the MS-CHAPv2 material. Any ideas?