<s>
LibreSSL	B-Language
is	O
an	O
open-source	B-Application
implementation	O
of	O
the	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS	O
)	O
protocol	O
.	O
</s>
<s>
The	O
implementation	O
is	O
named	O
after	O
Secure	B-Protocol
Sockets	I-Protocol
Layer	I-Protocol
(	O
SSL	O
)	O
,	O
the	O
deprecated	O
predecessor	O
of	O
TLS	O
,	O
for	O
which	O
support	O
was	O
removed	O
in	O
release	O
2.3.0	O
.	O
</s>
<s>
The	O
OpenBSD	B-Operating_System
project	I-Operating_System
forked	B-Application
LibreSSL	B-Language
from	O
OpenSSL	B-Language
1.0.1g	O
in	O
April	O
2014	O
as	O
a	O
response	O
to	O
the	O
Heartbleed	B-Error_Name
security	O
vulnerability	O
,	O
with	O
the	O
goals	O
of	O
modernizing	O
the	O
codebase	B-General_Concept
,	O
improving	O
security	O
,	O
and	O
applying	O
development	O
best	O
practices	O
.	O
</s>
<s>
After	O
the	O
Heartbleed	B-Error_Name
security	O
vulnerability	O
was	O
discovered	O
in	O
OpenSSL	B-Language
,	O
the	O
OpenBSD	B-Operating_System
team	O
audited	O
the	O
codebase	B-General_Concept
and	O
decided	O
it	O
was	O
necessary	O
to	O
fork	B-Application
OpenSSL	B-Language
to	O
remove	O
dangerous	O
code	O
.	O
</s>
<s>
The	O
libressl.org	O
domain	O
was	O
registered	O
on	O
11	O
April	O
2014	O
;	O
the	O
project	O
announced	O
the	O
name	O
on	O
22	O
April	O
2014	O
.	O
</s>
<s>
In	O
the	O
first	O
week	O
of	O
development	O
,	O
more	O
than	O
90,000	O
lines	O
of	O
C	B-Language
code	O
were	O
removed	O
.	O
</s>
<s>
Unused	O
code	O
was	O
removed	O
,	O
and	O
support	O
for	O
obsolete	O
operating	B-General_Concept
systems	I-General_Concept
(	O
Classic	B-Application
Mac	I-Application
OS	I-Application
,	O
NetWare	B-Operating_System
,	O
OS/2	B-Application
,	O
16-bit	B-Library
Windows	I-Library
)	O
and	O
some	O
older	O
operating	B-General_Concept
systems	I-General_Concept
(	O
OpenVMS	B-Operating_System
)	O
was	O
removed	O
.	O
</s>
<s>
LibreSSL	B-Language
was	O
initially	O
developed	O
as	O
an	O
intended	O
replacement	O
for	O
OpenSSL	B-Language
in	O
OpenBSD	B-Operating_System
5.6	O
,	O
and	O
was	O
ported	O
to	O
other	O
platforms	O
once	O
a	O
stripped-down	O
version	O
of	O
the	O
library	B-Library
was	O
stable	O
.	O
</s>
<s>
On	O
17	O
May	O
2014	O
,	O
Bob	O
Beck	O
presented	O
"	O
LibreSSL	B-Language
:	O
The	O
First	O
30	O
Days	O
,	O
and	O
What	O
The	O
Future	O
Holds	O
"	O
during	O
the	O
2014	O
BSDCan	O
conference	O
,	O
in	O
which	O
he	O
described	O
the	O
progress	O
made	O
in	O
the	O
first	O
month	O
.	O
</s>
<s>
On	O
5	O
June	O
2014	O
,	O
several	O
OpenSSL	B-Language
bugs	B-Error_Name
became	O
public	O
.	O
</s>
<s>
While	O
several	O
projects	O
were	O
notified	O
in	O
advance	O
,	O
LibreSSL	B-Language
was	O
not	O
;	O
Theo	O
de	O
Raadt	O
accused	O
the	O
OpenSSL	B-Language
developers	O
of	O
intentionally	O
withholding	O
this	O
information	O
from	O
OpenBSD	B-Operating_System
and	O
LibreSSL	B-Language
.	O
</s>
<s>
On	O
20	O
June	O
2014	O
,	O
Google	B-Application
created	O
another	O
fork	B-Application
of	O
OpenSSL	B-Language
called	O
BoringSSL	B-Protocol
,	O
and	O
promised	O
to	O
exchange	O
fixes	O
with	O
LibreSSL	B-Language
.	O
</s>
<s>
Google	B-Application
has	O
already	O
relicensed	O
some	O
of	O
its	O
contributions	O
under	O
the	O
ISC	B-License
license	I-License
,	O
as	O
it	O
was	O
requested	O
by	O
the	O
LibreSSL	B-Language
developers	O
.	O
</s>
<s>
On	O
21	O
June	O
2014	O
,	O
Theo	O
de	O
Raadt	O
welcomed	O
BoringSSL	B-Protocol
and	O
outlined	O
the	O
plans	O
for	O
LibreSSL-portable	O
.	O
</s>
<s>
Starting	O
on	O
8	O
July	O
,	O
code	O
porting	O
for	O
macOS	B-Application
and	O
Solaris	B-Application
began	O
,	O
while	O
the	O
initial	O
porting	O
to	O
Linux	B-Application
began	O
on	O
20	O
June	O
.	O
</s>
<s>
As	O
of	O
2021	O
,	O
OpenBSD	B-Operating_System
uses	O
LibreSSL	B-Language
as	O
the	O
primary	O
SSL	O
library	B-Library
.	O
</s>
<s>
Alpine	O
Linux	B-Application
supported	O
LibreSSL	B-Language
as	O
its	O
primary	O
TLS	O
library	B-Library
for	O
three	O
years	O
,	O
until	O
release	O
3.9.0	O
in	O
January	O
2019	O
.	O
</s>
<s>
Gentoo	B-Application
supported	O
LibreSSL	B-Language
until	O
February	O
2021	O
.	O
</s>
<s>
Python	B-Language
3.10	O
drops	O
LibreSSL	B-Language
support	O
after	O
being	O
supported	O
since	O
Python	B-Language
3.4.3	O
(	O
2015	O
)	O
.	O
</s>
<s>
LibreSSL	B-Language
is	O
the	O
default	O
provider	O
of	O
TLS	O
for	O
:	O
</s>
<s>
LibreSSL	B-Language
is	O
the	O
default	O
provider	O
of	O
TLS	O
for	O
these	O
now-discontinued	O
systems	O
:	O
</s>
<s>
LibreSSL	B-Language
is	O
a	O
selectable	O
provider	O
of	O
TLS	O
for	O
:	O
</s>
<s>
Changes	O
include	O
replacement	O
of	O
custom	O
memory	O
calls	O
to	O
ones	O
in	O
a	O
standard	B-Library
library	I-Library
(	O
for	O
example	O
,	O
strlcpy	O
,	O
calloc	B-Language
,	O
asprintf	O
,	O
reallocarray	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
This	O
process	O
may	O
help	O
later	O
on	O
to	O
catch	O
buffer	B-General_Concept
overflow	I-General_Concept
errors	O
with	O
more	O
advanced	O
memory	B-General_Concept
analysis	I-General_Concept
tools	O
or	O
by	O
observing	O
program	O
crashes	O
(	O
via	O
ASLR	O
,	O
use	O
of	O
the	O
NX	B-General_Concept
bit	I-General_Concept
,	O
stack	O
canaries	O
,	O
etc	O
.	O
</s>
<s>
Fixes	O
for	O
potential	O
double	O
free	O
scenarios	O
have	O
also	O
been	O
cited	O
in	O
the	O
VCS	B-Architecture
commit	B-Protocol
logs	O
(	O
including	O
explicit	O
assignments	O
of	O
null	O
pointer	O
values	O
)	O
.	O
</s>
<s>
There	O
have	O
been	O
extra	O
sanity	B-Error_Name
checks	I-Error_Name
also	O
cited	O
in	O
the	O
commit	B-Protocol
logs	O
related	O
to	O
ensuring	O
length	O
arguments	O
,	O
unsigned-to-signed	O
variable	O
assignments	O
,	O
pointer	O
values	O
,	O
and	O
method	O
returns	O
.	O
</s>
<s>
There	O
have	O
also	O
been	O
code	O
readability	O
updates	O
which	O
help	O
future	O
contributors	O
in	O
verifying	O
program	O
correctness	O
(	O
KNF	B-Operating_System
,	O
white-space	O
,	O
line-wrapping	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
Modification	O
or	O
removal	O
of	O
unneeded	O
method	O
wrappers	O
and	O
macros	O
also	O
help	O
with	O
code	O
readability	O
and	O
auditing	O
(	O
Error	O
and	O
I/O	B-Architecture
abstraction	I-Architecture
library	B-Library
references	O
)	O
.	O
</s>
<s>
Changes	O
were	O
made	O
to	O
ensure	O
that	O
LibreSSL	B-Language
will	O
be	O
year	B-Application
2038	I-Application
compatible	I-Application
along	O
with	O
maintaining	O
portability	O
for	O
other	O
similar	O
platforms	O
.	O
</s>
<s>
There	O
were	O
changes	O
to	O
help	O
ensure	O
proper	O
seeding	B-Algorithm
of	O
random	O
number	O
generator-based	O
methods	O
via	O
replacements	O
of	O
insecure	O
seeding	B-Algorithm
practices	O
(	O
taking	O
advantage	O
of	O
features	O
offered	O
by	O
the	O
kernel	B-Operating_System
itself	O
natively	O
)	O
.	O
</s>
<s>
In	O
terms	O
of	O
notable	O
additions	O
made	O
,	O
OpenBSD	B-Operating_System
has	O
added	O
support	O
for	O
newer	O
and	O
more	O
reputable	O
algorithms	O
(	O
ChaCha	O
stream	O
cipher	O
and	O
Poly1305	B-Algorithm
message	O
authentication	O
code	O
)	O
along	O
with	O
a	O
safer	O
set	O
of	O
elliptic	O
curves	O
(	O
brainpool	O
curves	O
from	O
RFC	O
5639	O
,	O
up	O
to	O
512	O
bits	O
in	O
strength	O
)	O
.	O
</s>
<s>
The	O
initial	O
release	O
of	O
LibreSSL	B-Language
added	O
a	O
number	O
of	O
features	O
:	O
the	O
ChaCha	O
and	O
Poly1305	B-Algorithm
algorithm	O
,	O
the	O
and	O
elliptic	O
curves	O
,	O
and	O
the	O
AES-GCM	B-Algorithm
and	O
ChaCha20-Poly1305	B-Algorithm
AEAD	B-Algorithm
modes	O
.	O
</s>
<s>
2.1.0	O
:	O
Automatic	O
ephemeral	B-General_Concept
EC	O
keys	O
.	O
</s>
<s>
2.1.2	O
:	O
Built-in	O
arc4random	O
implementation	O
on	O
macOS	B-Application
and	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
2.1.2	O
:	O
Reworked	O
GOST	B-Algorithm
cipher	O
suite	O
support	O
.	O
</s>
<s>
2.1.3	O
:	O
ALPN	B-Protocol
support	O
.	O
</s>
<s>
2.1.3	O
:	O
Support	O
for	O
SHA-256	B-Algorithm
and	O
Camellia	B-Algorithm
cipher	O
suites	O
.	O
</s>
<s>
2.1.4	O
:	O
Experimental	O
Windows	B-Application
binaries	O
.	O
</s>
<s>
2.1.5	O
:	O
Minor	O
update	O
mainly	O
for	O
improving	O
Windows	B-Application
support	O
,	O
first	O
working	O
32	O
-	O
and	O
64-bit	B-Device
binaries	O
.	O
</s>
<s>
2.2.0	O
:	O
AIX	B-Application
and	O
Cygwin	B-Language
support	O
.	O
</s>
<s>
2.2.1	O
:	O
Addition	O
of	O
EC_curve_nid2nist	O
and	O
EC_curve_nist2nid	O
from	O
OpenSSL	B-Language
,	O
initial	O
Windows	O
XP/2003	O
support	O
.	O
</s>
<s>
2.2.2	O
:	O
Defines	O
LIBRESSL_VERSION_NUMBER	O
,	O
added	O
TLS_*methods	O
as	O
a	O
replacement	O
for	O
the	O
SSLv23_*method	O
calls	O
,	O
cmake	B-Language
build	O
support	O
.	O
</s>
<s>
The	O
initial	O
release	O
of	O
LibreSSL	B-Language
disabled	O
a	O
number	O
of	O
features	O
by	O
default	O
.	O
</s>
<s>
Some	O
of	O
the	O
code	O
for	O
these	O
features	O
was	O
later	O
removed	O
,	O
including	O
Kerberos	B-Protocol
,	O
US-Export	O
ciphers	O
,	O
TLS	O
compression	O
,	O
DTLS	B-Protocol
heartbeat	O
,	O
SSL	O
v2	O
and	O
SSL	O
v3	O
.	O
</s>
<s>
2.1.1	O
:	O
Following	O
the	O
discovery	O
of	O
the	O
POODLE	B-Protocol
vulnerability	I-Protocol
in	O
the	O
legacy	O
SSL	O
3.0	O
protocol	O
,	O
LibreSSL	B-Language
now	O
disables	O
the	O
use	O
of	O
SSL	O
3.0	O
by	O
default	O
.	O
</s>
<s>
2.1.3	O
:	O
GOST	B-Algorithm
R	I-Algorithm
34.10-94	I-Algorithm
signature	O
authentication	O
.	O
</s>
<s>
2.2.2	O
:	O
Removal	O
of	O
SSL	O
3.0	O
from	O
the	O
openssl	B-Language
binary	O
,	O
removal	O
of	O
Internet	B-Application
Explorer	I-Application
6	O
workarounds	O
,	O
RSAX	O
engine	O
.	O
</s>
<s>
The	O
initial	O
release	O
of	O
LibreSSL	B-Language
has	O
removed	O
a	O
number	O
of	O
features	O
that	O
were	O
deemed	O
insecure	O
,	O
unnecessary	O
or	O
deprecated	O
as	O
part	O
of	O
OpenBSD	B-Operating_System
5.6	O
.	O
</s>
<s>
In	O
response	O
to	O
Heartbleed	B-Error_Name
,	O
the	O
heartbeat	O
functionality	O
was	O
one	O
of	O
the	O
first	O
features	O
to	O
be	O
removed	O
.	O
</s>
<s>
Support	O
for	O
obsolete	O
platforms	O
(	O
Classic	B-Application
Mac	I-Application
OS	I-Application
,	O
NetWare	B-Operating_System
,	O
OS/2	B-Application
,	O
16-bit	B-Library
Windows	I-Library
)	O
were	O
removed	O
.	O
</s>
<s>
Support	O
for	O
some	O
older	O
platforms	O
(	O
OpenVMS	B-Operating_System
)	O
was	O
removed	O
.	O
</s>
<s>
Support	O
for	O
platforms	O
that	O
do	O
not	O
exist	O
,	O
such	O
as	O
big-endian	O
i386	B-General_Concept
and	O
amd64	B-Device
.	O
</s>
<s>
The	O
IBM	B-Device
4758	I-Device
,	O
Broadcom	O
ubsec	O
,	O
Sureware	O
,	O
Nuron	O
,	O
GOST	B-Algorithm
,	O
GMP	O
,	O
CSwift	O
,	O
CHIL	O
,	O
CAPI	O
,	O
Atalla	O
and	O
AEP	O
engines	O
were	O
removed	O
due	O
to	O
irrelevance	O
of	O
hardware	O
or	O
dependency	O
on	O
non-free	B-Application
libraries	O
.	O
</s>
<s>
The	O
OpenSSL	B-Language
PRNG	B-Algorithm
was	O
removed	O
(	O
and	O
replaced	O
with	O
ChaCha20-based	O
implementation	O
of	O
arc4random	O
)	O
.	O
</s>
<s>
Preprocessor	B-Language
macros	I-Language
that	O
have	O
been	O
deemed	O
unnecessary	O
or	O
insecure	O
or	O
had	O
already	O
been	O
deprecated	O
in	O
OpenSSL	B-Language
for	O
a	O
long	O
time	O
(	O
e.g.	O
</s>
<s>
Older	O
unneeded	O
files	O
for	O
assembly	B-Language
language	I-Language
,	O
C	B-Language
,	O
and	O
Perl	B-Language
(	O
e.g.	O
</s>
<s>
MD2	B-Algorithm
,	O
SEED	O
functionality	O
.	O
</s>
<s>
The	O
Dual	B-Algorithm
EC	I-Algorithm
DRBG	I-Algorithm
algorithm	O
,	O
which	O
is	O
suspected	O
of	O
having	O
a	O
back	O
door	O
,	O
was	O
cut	O
along	O
with	O
support	O
for	O
the	O
FIPS	O
140-2	O
standard	O
that	O
required	O
it	O
.	O
</s>
<s>
Unused	O
protocols	O
and	O
insecure	O
algorithms	O
have	O
also	O
been	O
removed	O
,	O
including	O
the	O
support	O
for	O
FIPS	O
140-2	O
,	O
MD4/MD5	O
J-PAKE	B-Protocol
,	O
and	O
SRP	B-Protocol
.	O
</s>
<s>
One	O
of	O
the	O
complaints	O
of	O
OpenSSL	B-Language
was	O
the	O
number	O
of	O
open	O
bugs	B-Error_Name
reported	O
in	O
the	O
bug	B-Error_Name
tracker	O
that	O
had	O
gone	O
unfixed	O
for	O
years	O
.	O
</s>
<s>
Older	O
bugs	B-Error_Name
are	O
now	O
being	O
fixed	O
in	O
LibreSSL	B-Language
.	O
</s>
