Just a few quick notes.

MPPE support was started by Árpád Magosányi <mag@bunuel.tii.matav.hu> in 1994,
and was finished by Tim Hockin, Cobalt Networks Inc. <thockin@cobaltnet.com>
in 1999.  If you helped, and I don't know it (which could be) please notify
the maintainer of this code, and it will be rectified.  As far as I know, only i
Linux is supported (sorry - it's all we had available).

MPPE - Microsoft Point-to-Point Encryption uses rc4 (40 or 128 bit) as a
bi-directional encryption algorithm.  The keys are based on your MS-CHAP 
authentication info, so you must use chapms or chapms-v2.  Rc4 is owned by
RSA Data Security, and you may have to pay to use it, or not use it at all,
depending on your place of residence.  No author listed in this file claims
any responsibility for misuse of this software.  Copyright for some code is
owned by Eric Young (see ./linux/rc4.h for details).  Depending on where you 
got this code from (either in patch or tar.gz form), you may need to obtain 
the actual rc4 code from a different site.  The implementation of rc4 found in 
the SSLeay package, by Eric Young, version 0.6.6.  This package can be found
at ftp://ftp.psy.uq.oz.au/pub/Crypto/SSL/.  Newer versions than 0.6.6 may
require some minor source code or header file changes.  Once obtained, copy 
rc4.h and rc4_enc.c to the linux/ subdir of this package.

This is NOT a particularly secure mode of operation.  For maximum possible 
security using MPPE, it is advised in the RFC's to use the highest mode of
encryption that is legal, and to enable stateless mode (which renogotiates
keys with every packet).  Even with these precautions, MPPE is not very secure,
but anything is better than nothing, right?

That said, it seems to work pretty well, for what it is.  MSChap-v2 support 
was added by someone along the way, and MPPE needed some finishing.  It 
appears to work with Windows (tm) clients, with encryption specified.

How to use it:
* Compile this pppd, and teh associated kernel modules.
* Add +chapms and/or +chapms-v2 to your pppd command line.
* Add mppe-40 and/or mppe-128 and/or mppe-stateless to your pppd command line.
* Either load ppp_mppe.o manually or put this line in your /etc/conf.modules.
	alias 	ppp-compress-18 	ppp_mppe
* Go for it.


For further reading:
	Use the source, Luke.
	draft-ietf-pppext-mppe-03.txt (any RFC site should have this)
	draft-ietf-pppext-mppe-keys-00.txt (ditto)