mppe

from The Free On-line Dictionary of Computing (8 July 2008)

Microsoft Point to Point Encryption
MPPE

   <protocol> (MPPE) An {encryption} {protocol} that may be used
   with {PPTP} to provide an encrypted connection.

   (1998-09-24)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

MPPE
       Microsoft Point to Point Encryption (MS, cryptography, RFC 3078)