<s>
Encrypted	B-Protocol
Key	I-Protocol
Exchange	I-Protocol
(	O
also	O
known	O
as	O
EKE	O
)	O
is	O
a	O
family	O
of	O
password-authenticated	B-Protocol
key	I-Protocol
agreement	I-Protocol
methods	O
described	O
by	O
Steven	O
M	O
.	O
Bellovin	O
and	O
Michael	O
Merritt	O
.	O
</s>
<s>
Although	O
several	O
of	O
the	O
forms	O
of	O
EKE	O
in	O
this	O
paper	O
were	O
later	O
found	O
to	O
be	O
flawed	O
,	O
the	O
surviving	O
,	O
refined	O
,	O
and	O
enhanced	O
forms	O
of	O
EKE	O
effectively	O
make	O
this	O
the	O
first	O
method	O
to	O
amplify	O
a	O
shared	O
password	O
into	O
a	O
shared	B-Algorithm
key	I-Algorithm
,	O
where	O
the	O
shared	B-Algorithm
key	I-Algorithm
may	O
subsequently	O
be	O
used	O
to	O
provide	O
a	O
zero-knowledge	B-General_Concept
password	I-General_Concept
proof	I-General_Concept
or	O
other	O
functions	O
.	O
</s>
<s>
In	O
the	O
most	O
general	O
form	O
of	O
EKE	O
,	O
at	O
least	O
one	O
party	O
encrypts	O
an	O
ephemeral	O
(	O
one-time	O
)	O
public	O
key	O
using	O
a	O
password	O
,	O
and	O
sends	O
it	O
to	O
a	O
second	O
party	O
,	O
who	O
decrypts	O
it	O
and	O
uses	O
it	O
to	O
negotiate	O
a	O
shared	B-Algorithm
key	I-Algorithm
with	O
the	O
first	O
party	O
.	O
</s>
<s>
A	O
second	O
paper	O
describes	O
Augmented-EKE	O
,	O
and	O
introduced	O
the	O
concept	O
of	O
augmented	O
password-authenticated	B-Protocol
key	I-Protocol
agreement	I-Protocol
for	O
client/server	O
scenarios	O
.	O
</s>
<s>
A	O
version	O
of	O
EKE	O
based	O
on	O
Diffie	B-Protocol
–	I-Protocol
Hellman	I-Protocol
,	O
known	O
as	O
DH-EKE	O
,	O
has	O
survived	O
attack	O
and	O
has	O
led	O
to	O
improved	O
variations	O
,	O
such	O
as	O
the	O
PAK	O
family	O
of	O
methods	O
in	O
IEEE	O
P1363.2	O
.	O
</s>
<s>
Since	O
the	O
US	O
patent	O
on	O
EKE	O
expired	O
in	O
late	O
2011	O
,	O
an	O
EAP	B-Protocol
authentication	O
method	O
using	O
EKE	O
was	O
published	O
as	O
an	O
IETF	O
RFC	O
.	O
</s>
<s>
The	O
EAP	B-Protocol
method	O
uses	O
the	O
Diffie	B-Protocol
–	I-Protocol
Hellman	I-Protocol
variant	O
of	O
EKE	O
.	O
</s>
