<s>
s2n	B-Protocol
is	O
an	O
open-source	B-Application
C99	B-Language
implementation	O
of	O
the	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS	O
)	O
protocol	O
developed	O
by	O
Amazon	B-Application
Web	I-Application
Services	I-Application
(	O
AWS	B-Application
)	O
and	O
released	O
in	O
2015	O
.	O
</s>
<s>
It	O
was	O
developed	O
to	O
ensure	O
the	O
code	O
—	O
about	O
6,000	O
lines	O
long	O
—	O
would	O
be	O
easier	O
to	O
review	O
than	O
that	O
of	O
OpenSSL	B-Language
—	O
with	O
500,000	O
lines	O
,	O
70,000	O
of	O
which	O
are	O
involved	O
in	O
processing	O
TLS	O
.	O
</s>
<s>
s2n	B-Protocol
was	O
released	O
on	O
June	O
30	O
,	O
2015	O
on	O
GitHub	B-Application
.	O
</s>
<s>
AWS	B-Application
said	O
that	O
the	O
name	O
"	O
s2n	B-Protocol
"	O
stand	O
for	O
signal	O
to	O
noise	O
as	O
a	O
nod	O
"	O
to	O
the	O
almost	O
magical	O
act	O
of	O
encryption	O
—	O
disguising	O
meaningful	O
signals	O
,	O
like	O
your	O
critical	O
data	O
,	O
as	O
seemingly	O
random	O
noise	O
"	O
.	O
</s>
<s>
In	O
response	O
,	O
Amazon	O
's	O
s2n	B-Protocol
team	O
said	O
it	O
would	O
remove	O
CBC-mode	O
cipher	B-Protocol
suites	I-Protocol
and	O
take	O
code	O
from	O
BoringSSL	O
to	O
replace	O
its	O
own	O
CBC-mode	O
decryption	O
.	O
</s>
<s>
An	O
AWS	B-Application
Security	O
Blog	O
Post	O
said	O
that	O
it	O
did	O
not	O
impact	O
Amazon	O
,	O
AWS	B-Application
,	O
or	O
its	O
customers	O
because	O
they	O
had	O
never	O
been	O
used	O
in	O
a	O
production	O
environment	O
.	O
</s>
<s>
In	O
February	O
2017	O
,	O
Amazon	O
announced	O
that	O
s2n	B-Protocol
was	O
now	O
handling	O
100%	O
of	O
SSL	O
traffic	O
for	O
Amazon	B-General_Concept
S3	I-General_Concept
.	O
</s>
<s>
Common	O
TLS	O
extensions	O
supported	O
by	O
this	O
software	O
are	O
Server	B-Protocol
Name	I-Protocol
Indication	I-Protocol
,	O
Application-Layer	B-Protocol
Protocol	I-Protocol
Negotiation	I-Protocol
,	O
and	O
Online	B-Protocol
Certificate	I-Protocol
Status	I-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
s2n	B-Protocol
supports	O
the	O
main	O
ciphers	B-Application
in	O
use	O
today	O
,	O
such	O
as	O
AES	B-Algorithm
in	O
CBC	O
and	O
GCM	B-Algorithm
modes	I-Algorithm
,	O
3DES	B-Algorithm
and	O
RC4	B-Algorithm
.	O
</s>
<s>
It	O
also	O
provides	O
support	O
for	O
perfect	O
forward	O
secrecy	O
through	O
Diffie	O
–	O
Hellman	O
or	O
Elliptic-curve	B-Protocol
Diffie	I-Protocol
–	I-Protocol
Hellman	I-Protocol
ephemeral	B-General_Concept
keys	I-General_Concept
.	O
</s>
<s>
Weaker	O
ciphers	B-Application
and	O
key	O
exchange	O
modes	O
are	O
disabled	O
by	O
default	O
.	O
</s>
<s>
The	O
language	B-Application
bindings	I-Application
below	O
were	O
not	O
developed	O
by	O
AWS	B-Application
:	O
</s>
<s>
Lua	B-Language
:	O
</s>
<s>
Python	B-Language
:	O
</s>
