<s>
Tahoe-LAFS	B-General_Concept
(	O
Tahoe	O
Least-Authority	O
File	O
Store	O
)	O
is	O
a	O
free	B-Application
and	I-Application
open	I-Application
,	O
secure	O
,	O
decentralized	O
,	O
fault-tolerant	O
,	O
distributed	O
data	O
store	O
and	O
distributed	O
file	O
system	O
.	O
</s>
<s>
It	O
can	O
be	O
used	O
as	O
an	O
online	B-General_Concept
backup	I-General_Concept
system	O
,	O
or	O
to	O
serve	O
as	O
a	O
file	O
or	O
Web	O
host	O
similar	O
to	O
Freenet	B-Protocol
,	O
depending	O
on	O
the	O
front-end	B-Architecture
used	O
to	O
insert	O
and	O
access	O
files	O
in	O
the	O
Tahoe	O
system	O
.	O
</s>
<s>
Tahoe	O
can	O
also	O
be	O
used	O
in	O
a	O
RAID-like	O
fashion	O
using	O
multiple	O
disks	O
to	O
make	O
a	O
single	O
large	O
Redundant	B-Application
Array	I-Application
of	I-Application
Inexpensive	I-Application
Nodes	I-Application
(	O
RAIN	O
)	O
pool	O
of	O
reliable	O
data	O
storage	O
.	O
</s>
<s>
Tahoe-LAFS	B-General_Concept
was	O
started	O
in	O
2006	O
at	O
online	B-General_Concept
backup	I-General_Concept
services	I-General_Concept
company	O
All	O
My	O
Data	O
and	O
has	O
been	O
actively	O
developed	O
since	O
2007	O
.	O
</s>
<s>
When	O
All	O
My	O
Data	O
closed	O
in	O
2009	O
,	O
Tahoe-LAFS	B-General_Concept
became	O
a	O
free	B-Application
software	I-Application
project	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
or	O
The	O
Transitive	O
Grace	O
License	O
,	O
which	O
allows	O
owners	O
of	O
the	O
code	O
twelve	O
months	O
to	O
profit	O
from	O
their	O
work	O
before	O
releasing	O
it	O
.	O
</s>
<s>
In	O
2010	O
,	O
Tahoe-LAFS	B-General_Concept
was	O
mentioned	O
as	O
a	O
tool	O
against	O
censorship	O
by	O
the	O
Electronic	O
Frontier	O
Foundation	O
.	O
</s>
<s>
In	O
2013	O
,	O
it	O
was	O
one	O
of	O
the	O
hackathon	O
projects	O
at	O
the	O
GNU	B-Application
30th	O
anniversary	O
.	O
</s>
<s>
The	O
Tahoe-LAFS	B-General_Concept
Client	O
sends	O
an	O
unencrypted	O
file	O
via	O
a	O
web	O
API	O
to	O
the	O
HTTPS	O
Server	O
.	O
</s>
<s>
The	O
HTTPS	O
Server	O
passes	O
the	O
file	O
off	O
to	O
the	O
Tahoe-LAFS	B-General_Concept
Storage	O
client	O
which	O
encrypts	O
the	O
file	O
and	O
then	O
uses	O
erasure	O
coding	O
to	O
store	O
fragments	O
of	O
the	O
file	O
on	O
multiple	O
storage	O
drives	O
.	O
</s>
<s>
Tahoe-LAFS	B-General_Concept
features	O
"	O
provider-independent	O
security	O
"	O
,	O
in	O
that	O
the	O
integrity	O
and	O
confidentiality	O
of	O
the	O
files	O
are	O
guaranteed	O
by	O
the	O
algorithms	O
used	O
on	O
the	O
client	O
,	O
independent	O
of	O
the	O
storage	O
servers	O
,	O
which	O
may	O
fail	O
or	O
may	O
be	O
operated	O
by	O
untrusted	O
entities	O
.	O
</s>
<s>
Files	O
are	O
encrypted	O
using	O
AES	B-Algorithm
,	O
then	O
split	O
up	O
using	O
erasure	O
coding	O
,	O
such	O
that	O
only	O
a	O
subset	O
K	O
of	O
the	O
original	O
N	O
servers	O
storing	O
the	O
file	O
chunks	O
need	O
to	O
be	O
available	O
in	O
order	O
to	O
recreate	O
the	O
original	O
file	O
.	O
</s>
<s>
A	O
patched	O
version	O
of	O
Tahoe-LAFS	B-General_Concept
exists	O
from	O
2011	O
,	O
and	O
was	O
made	O
to	O
run	O
on	O
anonymous	O
networks	O
such	O
as	O
I2P	B-Protocol
,	O
with	O
support	O
for	O
multiple	O
introducers	O
.	O
</s>
<s>
It	O
is	O
distributed	O
from	O
a	O
site	O
within	O
the	O
I2P	B-Protocol
network	O
.	O
</s>
<s>
In	O
contrast	O
to	O
normal	O
Tahoe-LAFS	B-General_Concept
operation	O
,	O
when	O
I2P	B-Protocol
and	O
Tahoe-LAFS	B-General_Concept
are	O
used	O
together	O
the	O
location	O
of	O
the	O
nodes	O
is	O
disguised	O
.	O
</s>
