<s>
Microsoft	B-Protocol
Point-to-Point	I-Protocol
Encryption	I-Protocol
(	O
MPPE	O
)	O
encrypts	O
data	O
in	O
Point-to-Point	B-Protocol
Protocol	I-Protocol
(	O
PPP	O
)	O
-based	O
dial-up	O
connections	O
or	O
Point-to-Point	B-Protocol
Tunneling	I-Protocol
Protocol	I-Protocol
(	O
PPTP	B-Protocol
)	O
virtual	B-Application
private	I-Application
network	I-Application
(	O
VPN	B-Application
)	O
connections	O
.	O
</s>
<s>
MPPE	O
provides	O
data	O
security	O
for	O
the	O
PPTP	B-Protocol
connection	O
that	O
is	O
between	O
the	O
VPN	B-Application
client	I-Application
and	O
the	O
VPN	B-Application
server	I-Application
.	O
</s>
<s>
MPPE	O
alone	O
does	O
not	O
compress	O
or	O
expand	O
data	O
,	O
but	O
the	O
protocol	O
is	O
often	O
used	O
in	O
conjunction	O
with	O
Microsoft	B-Device
Point-to-Point	I-Device
Compression	I-Device
which	O
compresses	O
data	O
across	O
PPP	O
or	O
VPN	B-Application
links	O
.	O
</s>
<s>
RFC	O
3078	O
,	O
which	O
defines	O
this	O
protocol	O
,	O
defines	O
RC4	B-Algorithm
with	O
either	O
40-bit	O
or	O
128-bit	O
key	O
lengths	O
as	O
the	O
only	O
encryption	O
options	O
with	O
this	O
protocol	O
.	O
</s>
