<s>
Internet	B-Protocol
Security	I-Protocol
Association	I-Protocol
and	I-Protocol
Key	I-Protocol
Management	I-Protocol
Protocol	I-Protocol
(	O
ISAKMP	B-Protocol
)	O
is	O
a	O
protocol	O
defined	O
by	O
RFC	O
2408	O
for	O
establishing	O
Security	B-Protocol
association	I-Protocol
(	O
SA	O
)	O
and	O
cryptographic	O
keys	O
in	O
an	O
Internet	O
environment	O
.	O
</s>
<s>
ISAKMP	B-Protocol
only	O
provides	O
a	O
framework	O
for	O
authentication	O
and	O
key	O
exchange	O
and	O
is	O
designed	O
to	O
be	O
key	O
exchange	O
independent	O
;	O
protocols	O
such	O
as	O
Internet	B-Protocol
Key	I-Protocol
Exchange	I-Protocol
(	O
IKE	B-Protocol
)	O
and	O
Kerberized	B-Protocol
Internet	I-Protocol
Negotiation	I-Protocol
of	I-Protocol
Keys	I-Protocol
(	O
KINK	O
)	O
provide	O
authenticated	O
keying	O
material	O
for	O
use	O
with	O
ISAKMP	B-Protocol
.	O
</s>
<s>
For	O
example	O
:	O
IKE	B-Protocol
describes	O
a	O
protocol	O
using	O
part	O
of	O
Oakley	B-Protocol
and	O
part	O
of	O
SKEME	O
in	O
conjunction	O
with	O
ISAKMP	B-Protocol
to	O
obtain	O
authenticated	O
keying	O
material	O
for	O
use	O
with	O
ISAKMP	B-Protocol
,	O
and	O
for	O
other	O
security	B-Protocol
associations	I-Protocol
such	O
as	O
AH	O
and	O
ESP	O
for	O
the	O
IETF	O
IPsec	B-Protocol
DOI	O
.	O
</s>
<s>
ISAKMP	B-Protocol
defines	O
the	O
procedures	O
for	O
authenticating	O
a	O
communicating	O
peer	O
,	O
creation	O
and	O
management	O
of	O
Security	B-Protocol
Associations	I-Protocol
,	O
key	O
generation	O
techniques	O
and	O
threat	O
mitigation	O
(	O
e.g.	O
</s>
<s>
As	O
a	O
framework	O
,	O
ISAKMP	B-Protocol
typically	O
utilizes	O
IKE	B-Protocol
for	O
key	O
exchange	O
,	O
although	O
other	O
methods	O
have	O
been	O
implemented	O
such	O
as	O
Kerberized	B-Protocol
Internet	I-Protocol
Negotiation	I-Protocol
of	I-Protocol
Keys	I-Protocol
.	O
</s>
<s>
ISAKMP	B-Protocol
is	O
distinct	O
from	O
key	B-Protocol
exchange	I-Protocol
protocols	I-Protocol
in	O
order	O
to	O
cleanly	O
separate	O
the	O
details	O
of	O
security	B-Protocol
association	I-Protocol
management	O
(	O
and	O
key	O
management	O
)	O
from	O
the	O
details	O
of	O
key	O
exchange	O
.	O
</s>
<s>
There	O
may	O
be	O
many	O
different	O
key	B-Protocol
exchange	I-Protocol
protocols	I-Protocol
,	O
each	O
with	O
different	O
security	O
properties	O
.	O
</s>
<s>
ISAKMP	B-Protocol
serves	O
as	O
this	O
common	O
framework	O
.	O
</s>
<s>
ISAKMP	B-Protocol
can	O
be	O
implemented	O
over	O
any	O
transport	O
protocol	O
.	O
</s>
<s>
All	O
implementations	O
must	O
include	O
send	O
and	O
receive	O
capability	O
for	O
ISAKMP	B-Protocol
using	O
UDP	B-Protocol
on	O
port	O
500	O
.	O
</s>
<s>
OpenBSD	B-Operating_System
first	O
implemented	O
ISAKMP	B-Protocol
in	O
1998	O
via	O
its	O
software	O
.	O
</s>
<s>
The	O
IPsec	B-Protocol
Services	O
Service	O
in	O
Microsoft	B-Application
Windows	I-Application
handles	O
this	O
functionality	O
.	O
</s>
<s>
The	O
KAME	B-Application
project	I-Application
implements	O
ISAKMP	B-Protocol
for	O
Linux	O
and	O
most	O
other	O
open	O
source	O
BSDs	B-Operating_System
.	O
</s>
<s>
Modern	O
Cisco	O
routers	O
implement	O
ISAKMP	B-Protocol
for	O
VPN	O
negotiation	O
.	O
</s>
<s>
Leaked	O
NSA	O
presentations	O
released	O
by	O
Der	O
Spiegel	O
indicate	O
that	O
ISAKMP	B-Protocol
is	O
being	O
exploited	O
in	O
an	O
unknown	O
manner	O
to	O
decrypt	O
IPSec	B-Protocol
traffic	O
,	O
as	O
is	O
IKE	B-Protocol
.	O
</s>
<s>
The	O
researchers	O
who	O
discovered	O
the	O
Logjam	B-Protocol
attack	I-Protocol
state	O
that	O
breaking	O
a	O
1024-bit	O
Diffie	B-Protocol
–	I-Protocol
Hellman	I-Protocol
group	I-Protocol
would	O
break	O
66%	O
of	O
VPN	O
servers	O
,	O
18%	O
of	O
the	O
top	O
million	O
HTTPS	O
domains	O
,	O
and	O
26%	O
of	O
SSH	O
servers	O
,	O
which	O
is	O
consistent	O
with	O
the	O
leaks	O
according	O
to	O
the	O
researchers	O
.	O
</s>
