<s>
Tutanota	B-Operating_System
is	O
an	O
end-to-end	O
encrypted	B-Protocol
email	I-Protocol
app	O
and	O
a	O
freemium	O
secure	B-Protocol
email	I-Protocol
service	O
.	O
</s>
<s>
As	O
of	O
March	O
2017	O
,	O
Tutanota	B-Operating_System
's	O
owners	O
claimed	O
to	O
have	O
over	O
2	O
million	O
users	O
of	O
the	O
product	O
.	O
</s>
<s>
Tutanota	B-Operating_System
is	O
derived	O
from	O
Latin	O
and	O
contains	O
the	O
words	O
"	O
tuta	O
"	O
and	O
"	O
nota	O
"	O
which	O
means	O
"	O
secure	O
message	O
"	O
.	O
</s>
<s>
The	O
goal	O
of	O
the	O
developers	O
for	O
Tutanota	B-Operating_System
is	O
to	O
fight	O
for	O
email	O
privacy	O
.	O
</s>
<s>
Since	O
2014	O
,	O
the	O
software	O
has	O
been	O
open-sourced	O
and	O
can	O
be	O
reviewed	O
by	O
outsiders	O
on	O
GitHub	B-Application
.	O
</s>
<s>
In	O
August	O
2018	O
,	O
Tutanota	B-Operating_System
became	O
the	O
first	O
email	O
service	O
provider	O
to	O
release	O
their	O
app	O
on	O
F-Droid	B-Application
,	O
removing	O
all	O
dependence	O
on	O
proprietary	O
code	O
.	O
</s>
<s>
This	O
was	O
part	O
of	O
a	O
full	O
remake	O
of	O
the	O
app	O
,	O
which	O
removed	O
dependence	O
on	O
GCM	O
for	O
notifications	O
by	O
replacing	O
it	O
with	O
SSE	B-Language
.	O
</s>
<s>
In	O
November	O
2020	O
,	O
the	O
Cologne	O
court	O
ordered	O
monitoring	O
of	O
a	O
single	O
Tutanota	B-Operating_System
account	O
that	O
had	O
been	O
used	O
for	O
an	O
extortion	O
attempt	O
.	O
</s>
<s>
Tutanota	B-Operating_System
offers	O
end-to-end	O
encryption	O
for	O
emails	O
sent	O
from	O
one	O
Tutanota	B-Operating_System
user	O
to	O
another	O
.	O
</s>
<s>
Tutanota	B-Operating_System
also	O
encrypts	O
all	O
emails	O
and	O
contacts	O
stored	O
in	O
their	O
servers	O
,	O
"	O
except	O
for	O
email	O
addresses	O
of	O
users	O
as	O
well	O
as	O
senders	O
and	O
recipients	O
of	O
emails	O
"	O
and	O
"	O
date	O
of	O
an	O
email	O
sent	O
or	O
received	O
"	O
.	O
</s>
<s>
Emails	O
sent	O
non-encrypted	O
,	O
are	O
encrypted	O
only	O
between	O
the	O
Tutanota	B-Operating_System
user	O
and	O
Tutanota	B-Operating_System
servers	O
,	O
and	O
then	O
sent	O
unencrypted	O
to	O
destination	O
user	O
.	O
</s>
<s>
Tutanota	B-Operating_System
uses	O
a	O
standardized	O
,	O
hybrid	O
method	O
consisting	O
of	O
a	O
symmetrical	O
and	O
an	O
asymmetrical	O
algorithm	O
-	O
AES	B-Algorithm
with	O
a	O
length	O
of	O
128	O
bit	O
and	O
RSA	B-Architecture
with	O
2048	O
bit	O
.	O
</s>
<s>
To	O
external	O
recipients	O
who	O
do	O
not	O
use	O
Tutanota	B-Operating_System
a	O
notification	O
is	O
sent	O
with	O
a	O
link	O
to	O
a	O
temporary	O
Tutanota	B-Operating_System
account	O
.	O
</s>
<s>
Tutanota	B-Operating_System
deletes	O
free	O
accounts	O
that	O
have	O
not	O
been	O
logged	O
into	O
for	O
6	O
months	O
.	O
</s>
<s>
According	O
to	O
Tutanota	B-Operating_System
,	O
this	O
happens	O
because	O
of	O
security	O
reasons	O
and	O
for	O
keeping	O
the	O
service	O
free	O
.	O
</s>
<s>
Tutanota	B-Operating_System
has	O
also	O
been	O
GDPR	O
compliant	O
since	O
2018	O
.	O
</s>
<s>
Tutanota	B-Operating_System
has	O
been	O
blocked	O
in	O
Egypt	O
since	O
October	O
2019	O
,	O
and	O
blocked	O
in	O
Russia	O
since	O
February	O
2020	O
for	O
unknown	O
reasons	O
(	O
although	O
believed	O
to	O
be	O
tied	O
to	O
recent	O
actions	O
against	O
services	O
operating	O
outside	O
of	O
the	O
country	O
,	O
especially	O
those	O
that	O
involve	O
encrypted	O
communications	O
)	O
.	O
</s>
<s>
Although	O
Tutanota	B-Operating_System
has	O
been	O
blocked	O
in	O
these	O
countries	O
,	O
users	O
still	O
access	O
its	O
service	O
via	O
Tor	O
or	O
VPN	O
.	O
</s>
