<s>
SNOW	O
1.0	O
,	O
SNOW	B-Algorithm
2.0	I-Algorithm
,	O
and	O
SNOW	O
3G	O
are	O
word-based	O
synchronous	O
stream	B-Algorithm
ciphers	I-Algorithm
developed	O
by	O
Thomas	O
Johansson	O
and	O
Patrik	O
Ekdahl	O
at	O
Lund	O
University	O
.	O
</s>
<s>
The	O
cipher	O
consists	O
of	O
a	O
combination	O
of	O
a	O
LFSR	B-Architecture
and	O
a	O
Finite	B-Architecture
State	I-Architecture
Machine	I-Architecture
(	O
FSM	O
)	O
where	O
the	O
LFSR	B-Architecture
also	O
feeds	O
the	O
next	O
state	O
function	O
of	O
the	O
FSM	O
.	O
</s>
<s>
It	O
has	O
been	O
found	O
that	O
related	O
keys	O
exist	O
both	O
for	O
SNOW	B-Algorithm
2.0	I-Algorithm
and	O
SNOW	O
3G	O
,	O
allowing	O
attacks	O
against	O
SNOW	B-Algorithm
2.0	I-Algorithm
in	O
the	O
related-key	O
model	O
.	O
</s>
<s>
SNOW	B-Algorithm
2.0	I-Algorithm
is	O
one	O
out	O
of	O
stream	B-Algorithm
ciphers	I-Algorithm
chosen	O
for	O
ISO/IEC	O
standard	O
ISO/IEC	O
18033-4	O
.	O
</s>
<s>
SNOW	O
3G	O
is	O
chosen	O
as	O
the	O
stream	B-Algorithm
cipher	I-Algorithm
for	O
the	O
3GPP	O
encryption	O
algorithms	O
UEA2	O
and	O
UIA2	O
.	O
</s>
