<s>
AES-GCM-SIV	B-Algorithm
is	O
a	O
mode	B-Algorithm
of	I-Algorithm
operation	I-Algorithm
for	O
the	O
Advanced	B-Algorithm
Encryption	I-Algorithm
Standard	I-Algorithm
which	O
provides	O
similar	O
performance	O
to	O
Galois/Counter	B-Algorithm
Mode	I-Algorithm
as	O
well	O
as	O
misuse	O
resistance	O
in	O
the	O
event	O
of	O
the	O
reuse	O
of	O
a	O
cryptographic	O
nonce	O
.	O
</s>
<s>
AES-GCM-SIV	B-Algorithm
is	O
designed	O
to	O
preserve	O
both	O
privacy	O
and	O
integrity	O
even	O
if	O
nonces	O
are	O
repeated	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
AES-GCM-SIV	B-Algorithm
is	O
an	O
ideal	O
choice	O
in	O
cases	O
that	O
unique	O
nonces	O
cannot	O
be	O
guaranteed	O
,	O
such	O
as	O
multiple	O
servers	O
or	O
network	O
devices	O
encrypting	O
messages	O
under	O
the	O
same	O
key	O
without	O
coordination	O
.	O
</s>
<s>
Like	O
Galois/Counter	B-Algorithm
Mode	I-Algorithm
,	O
AES-GCM-SIV	B-Algorithm
combines	O
the	O
well-known	O
counter	O
mode	O
of	O
encryption	O
with	O
the	O
Galois	O
mode	O
of	O
authentication	O
.	O
</s>
<s>
The	O
key	O
feature	O
is	O
the	O
use	O
of	O
a	O
synthetic	O
initialization	B-Algorithm
vector	I-Algorithm
which	O
is	O
computed	O
with	O
Galois	O
field	O
multiplication	O
using	O
a	O
construction	O
called	O
POLYVAL	O
(	O
a	O
little-endian	O
variant	O
of	O
Galois/Counter	B-Algorithm
Mode	I-Algorithm
's	O
GHASH	B-Algorithm
)	O
.	O
</s>
<s>
Note	O
that	O
GHASH	B-Algorithm
is	O
defined	O
over	O
the	O
"	O
reverse	O
"	O
polynomial	O
:	O
</s>
