<s>
Fortuna	B-Algorithm
is	O
a	O
cryptographically	B-Algorithm
secure	I-Algorithm
pseudorandom	I-Algorithm
number	I-Algorithm
generator	I-Algorithm
(	O
PRNG	O
)	O
devised	O
by	O
Bruce	O
Schneier	O
and	O
Niels	O
Ferguson	O
and	O
published	O
in	O
2003	O
.	O
</s>
<s>
It	O
is	O
named	O
after	O
Fortuna	B-Algorithm
,	O
the	O
Roman	O
goddess	O
of	O
chance	O
.	O
</s>
<s>
FreeBSD	B-Operating_System
uses	O
Fortuna	B-Algorithm
for	O
/dev/random	B-Application
and	O
/dev/urandom	B-Application
is	O
symbolically	O
linked	O
to	O
it	O
since	O
FreeBSD	B-Operating_System
11	O
.	O
</s>
<s>
Apple	O
OSes	O
have	O
switched	O
to	O
Fortuna	B-Algorithm
since	O
2020	O
Q1	O
.	O
</s>
<s>
The	O
seed	B-Algorithm
file	O
,	O
which	O
stores	O
enough	O
state	O
to	O
enable	O
the	O
computer	O
to	O
start	O
generating	O
random	O
numbers	O
as	O
soon	O
as	O
it	O
has	O
booted	O
.	O
</s>
<s>
Practical	O
Cryptography	O
suggests	O
AES	B-Algorithm
,	O
Serpent	B-Algorithm
or	O
Twofish	B-Algorithm
.	O
</s>
<s>
Reseeding	O
is	O
performed	O
by	O
hashing	O
the	O
specified	O
entropy	O
pools	O
into	O
the	O
block	O
cipher	O
's	O
key	O
using	O
two	O
iterations	O
of	O
SHA-256	B-Algorithm
.	O
</s>
<s>
Fortuna	B-Algorithm
uses	O
32	O
pools	O
,	O
and	O
restricts	O
reseeding	O
to	O
happen	O
at	O
most	O
10	O
times	O
per	O
second	O
.	O
</s>
<s>
Fortuna	B-Algorithm
differs	O
from	O
the	O
earlier	O
Yarrow	B-Algorithm
algorithm	I-Algorithm
family	O
of	O
Schneier	O
,	O
Kelsey	O
and	O
Ferguson	O
mostly	O
in	O
its	O
handling	O
of	O
the	O
entropy	O
accumulator	O
.	O
</s>
<s>
Yarrow	O
required	O
each	O
source	O
of	O
entropy	O
to	O
be	O
accompanied	O
by	O
a	O
mechanism	O
for	O
estimating	O
the	O
actual	O
entropy	O
supplied	O
,	O
and	O
used	O
only	O
two	O
pools	O
;	O
and	O
its	O
suggested	O
embodiment	O
(	O
called	O
Yarrow-160	O
)	O
used	O
SHA-1	B-Algorithm
rather	O
than	O
iterated	O
SHA-256	B-Algorithm
.	O
</s>
<s>
An	O
analysis	O
and	O
a	O
proposed	O
improvement	O
of	O
Fortuna	B-Algorithm
was	O
made	O
in	O
2014	O
.	O
</s>
