<s>
Enigmail	B-Operating_System
is	O
a	O
data	O
encryption	O
and	O
decryption	O
extension	B-Operating_System
for	O
Mozilla	B-Application
Thunderbird	I-Application
and	O
the	O
Postbox	B-Protocol
that	O
provides	O
OpenPGP	O
public	B-Application
key	I-Application
e-mail	O
encryption	O
and	O
signing	O
.	O
</s>
<s>
Enigmail	B-Operating_System
works	O
under	O
Microsoft	B-Application
Windows	I-Application
,	O
Unix-like	B-Operating_System
,	O
and	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Enigmail	B-Operating_System
can	O
operate	O
with	O
other	O
mail	O
clients	O
compatible	O
with	O
PGP/MIME	O
and	O
inline	O
PGP	O
such	O
as	O
:	O
Microsoft	B-Application
Outlook	I-Application
with	O
Gpg4win	O
package	O
installed	O
,	O
Gnome	B-Language
Evolution	I-Language
,	O
KMail	O
,	O
Claws	B-Language
Mail	I-Language
,	O
Gnus	B-Operating_System
,	O
Mutt	B-Device
.	O
</s>
<s>
Its	O
cryptographic	O
functionality	O
is	O
handled	O
by	O
GNU	B-Application
Privacy	I-Application
Guard	I-Application
.	O
</s>
<s>
In	O
their	O
default	O
configuration	O
,	O
Thunderbird	B-Application
and	O
SeaMonkey	O
provide	O
e-mail	O
encryption	O
and	O
signing	O
using	O
S/MIME	B-Protocol
,	O
which	O
relies	O
on	O
X.509	O
keys	O
provided	O
by	O
a	O
centralised	O
certificate	B-Architecture
authority	I-Architecture
.	O
</s>
<s>
Enigmail	B-Operating_System
adds	O
an	O
alternative	O
mechanism	O
where	O
cooperating	O
users	O
can	O
instead	O
use	O
keys	O
provided	O
by	O
a	O
web	O
of	O
trust	O
,	O
which	O
relies	O
on	O
multiple	O
users	O
to	O
endorse	O
the	O
authenticity	O
of	O
the	O
sender	O
's	O
and	O
recipient	O
's	O
credentials	O
.	O
</s>
<s>
Enigmail	B-Operating_System
was	O
first	O
released	O
in	O
2001	O
by	O
Ramalingam	O
Saravanan	O
,	O
and	O
since	O
2003	O
maintained	O
by	O
Patrick	O
Brunschwig	O
.	O
</s>
<s>
Both	O
Enigmail	B-Operating_System
and	O
GNU	B-Application
Privacy	I-Application
Guard	I-Application
are	O
free	B-Application
,	O
open-source	B-Application
software	I-Application
.	O
</s>
<s>
Enigmail	B-Operating_System
with	O
Thunderbird	B-Application
is	O
now	O
the	O
most	O
popular	O
PGP	O
setup	O
.	O
</s>
<s>
Enigmail	B-Operating_System
has	O
announced	O
its	O
support	O
for	O
the	O
new	O
"	O
pretty	O
Easy	O
privacy	O
"	O
(	O
p≡p	O
)	O
encryption	O
scheme	O
in	O
a	O
joint	O
Thunderbird	B-Application
extension	B-Operating_System
to	O
be	O
released	O
in	O
December	O
2015	O
.	O
</s>
<s>
Enigmail	B-Operating_System
also	O
supports	O
Autocrypt	O
exchange	O
of	O
cryptographic	O
keys	O
since	O
version	O
2.0	O
.	O
</s>
<s>
In	O
October	O
2019	O
,	O
the	O
developers	O
of	O
Thunderbird	B-Application
announced	O
built-in	O
support	O
for	O
encryption	O
and	O
signing	O
based	O
on	O
OpenPGP	O
Thunderbird	B-Application
78	O
to	O
replace	O
the	O
Enigmail	B-Operating_System
add-on	B-Operating_System
.	O
</s>
<s>
The	O
background	O
is	O
a	O
change	O
in	O
the	O
code	O
base	O
of	O
Thunderbird	B-Application
,	O
removing	O
support	O
for	O
legacy	O
add-ons	B-Operating_System
.	O
</s>
<s>
Since	O
this	O
would	O
require	O
a	O
rewrite	O
from	O
scratch	O
for	O
Enigmail	B-Operating_System
,	O
Patrick	O
Brunschwig	O
instead	O
supports	O
the	O
Thunderbird	B-Application
team	O
in	O
a	O
native	O
implementation	O
in	O
Thunderbird	B-Application
.	O
</s>
<s>
Enigmail	B-Operating_System
will	O
be	O
maintained	O
for	O
Thunderbird	B-Application
68	O
until	O
6	O
months	O
after	O
the	O
release	O
of	O
Thunderbird	B-Application
78	O
.	O
</s>
<s>
The	O
support	O
of	O
Enigmail	B-Operating_System
for	O
Postbox	B-Protocol
will	O
be	O
unaffected	O
.	O
</s>
