<s>
Gravatar	B-General_Concept
(	O
a	O
portmanteau	O
of	O
globally	O
recognized	O
avatar	B-Application
)	O
is	O
a	O
service	O
for	O
providing	O
globally	O
unique	O
avatars	B-Application
and	O
was	O
created	O
by	O
Tom	O
Preston-Werner	O
.	O
</s>
<s>
Since	O
2007	O
,	O
it	O
has	O
been	O
owned	O
by	O
Automattic	O
,	O
having	O
integrated	O
it	O
into	O
their	O
WordPress.com	B-Protocol
blogging	O
platform	O
.	O
</s>
<s>
On	O
Gravatar	B-General_Concept
,	O
users	O
can	O
register	O
an	O
account	O
based	O
on	O
their	O
email	O
address	O
,	O
and	O
upload	O
an	O
image	O
of	O
their	O
choice	O
to	O
be	O
associated	O
with	O
that	O
email	O
address	O
.	O
</s>
<s>
Gravatar	B-General_Concept
plugins	B-Application
are	O
available	O
for	O
popular	O
blogging	O
software	O
;	O
when	O
the	O
user	O
posts	O
a	O
comment	O
on	O
such	O
a	O
blog	O
that	O
requires	O
an	O
email	O
address	O
,	O
the	O
blogging	O
software	O
checks	O
whether	O
that	O
email	O
address	O
has	O
an	O
associated	O
avatar	B-Application
at	O
Gravatar	B-General_Concept
.	O
</s>
<s>
If	O
so	O
,	O
the	O
Gravatar	B-General_Concept
is	O
shown	O
along	O
with	O
the	O
comment	O
.	O
</s>
<s>
Gravatar	B-General_Concept
support	O
is	O
provided	O
natively	O
in	O
WordPress	B-Application
as	O
of	O
v2.5	O
and	O
in	O
web	O
based	O
project	O
management	O
application	O
Redmine	B-Operating_System
beginning	O
with	O
version	O
0.8	O
.	O
</s>
<s>
Support	O
for	O
Gravatar	B-General_Concept
is	O
also	O
provided	O
via	O
third-party	O
modules	O
for	O
web	O
content	B-Protocol
management	I-Protocol
systems	I-Protocol
such	O
as	O
Drupal	B-Application
and	O
MODX	B-Application
.	O
</s>
<s>
A	O
user	O
's	O
profile	O
data	O
is	O
available	O
in	O
a	O
number	O
of	O
metadata	O
standards	O
,	O
including	O
hCard	B-General_Concept
,	O
JSON	B-General_Concept
,	O
XML	B-Protocol
,	O
PHP	B-Application
,	O
and	O
vCard	O
as	O
well	O
as	O
via	O
QR	O
codes	O
.	O
</s>
<s>
The	O
raw	O
data	O
formats	O
(	O
JSON	B-General_Concept
,	O
XML	B-Protocol
,	O
and	O
PHP	B-Application
)	O
use	O
the	O
Portable	B-Application
Contacts	I-Application
standard	O
.	O
</s>
<s>
A	O
Gravatar	B-General_Concept
image	O
can	O
be	O
up	O
to	O
2048	O
pixels	B-Algorithm
wide	O
,	O
is	O
always	O
square	O
and	O
is	O
displayed	O
at	O
80	O
by	O
80	O
pixels	B-Algorithm
by	O
default	O
.	O
</s>
<s>
If	O
the	O
uploaded	O
avatar	B-Application
is	O
larger	O
or	O
smaller	O
,	O
the	O
avatar	B-Application
is	O
scaled	O
appropriately	O
.	O
</s>
<s>
Each	O
Gravatar	B-General_Concept
is	O
rated	O
with	O
an	O
MPAA-style	O
age	O
recommendation	O
,	O
allowing	O
webmasters	O
to	O
control	O
the	O
content	O
of	O
the	O
Gravatars	B-General_Concept
displayed	O
on	O
their	O
website	O
.	O
</s>
<s>
Webmasters	O
can	O
also	O
configure	O
their	O
system	O
to	O
automatically	O
display	O
an	O
Identicon	B-Error_Name
when	O
a	O
user	O
has	O
no	O
registered	O
Gravatar	B-General_Concept
.	O
</s>
<s>
For	O
some	O
time	O
,	O
the	O
Gravatar	B-General_Concept
service	O
remained	O
unmaintained	O
.	O
</s>
<s>
The	O
maker	O
became	O
busy	O
with	O
working	O
on	O
a	O
new	O
version	O
of	O
the	O
service	O
,	O
as	O
Gravatar	B-General_Concept
's	O
popularity	O
grew	O
and	O
more	O
bandwidth	O
was	O
required	O
.	O
</s>
<s>
On	O
16	O
February	O
2007	O
,	O
"	O
Gravatar	B-General_Concept
2.0	O
"	O
was	O
launched	O
.	O
</s>
<s>
Support	O
for	O
two	O
gravatars	B-General_Concept
per	O
account	O
was	O
added	O
,	O
between	O
which	O
the	O
user	O
can	O
easily	O
switch	O
.	O
</s>
<s>
"	O
Gravatar	B-General_Concept
Premium	O
"	O
was	O
also	O
launched	O
,	O
allowing	O
unlimited	O
email	O
addresses	O
and	O
Gravatars	B-General_Concept
per	O
account	O
.	O
</s>
<s>
On	O
11	O
June	O
2007	O
,	O
Tom	O
Preston-Werner	O
announced	O
that	O
32,000	O
new	O
users	O
had	O
signed	O
up	O
since	O
the	O
launch	O
of	O
Gravatar	B-General_Concept
2.0	O
.	O
</s>
<s>
On	O
18	O
October	O
2007	O
,	O
Automattic	O
acquired	O
Gravatar	B-General_Concept
.	O
</s>
<s>
Matt	O
Mullenweg	O
announced	O
on	O
The	O
Big	O
Web	O
Show	O
on	O
2	O
December	O
2010	O
that	O
Gravatar	B-General_Concept
was	O
serving	O
approximately	O
20	O
billion	O
images	O
per	O
day	O
.	O
</s>
<s>
Gravatars	B-General_Concept
are	O
loaded	O
from	O
the	O
Gravatar	B-General_Concept
web	B-Application
server	I-Application
,	O
using	O
a	O
URL	O
containing	O
an	O
MD5	B-Algorithm
hash	I-Algorithm
of	O
the	O
associated	O
email	O
address	O
.	O
</s>
<s>
This	O
method	O
has	O
,	O
however	O
,	O
been	O
shown	O
to	O
be	O
vulnerable	O
to	O
dictionary	O
attacks	O
and	O
rainbow	B-Algorithm
table	I-Algorithm
approaches	O
.	O
</s>
<s>
In	O
2009	O
,	O
it	O
was	O
demonstrated	O
that	O
over	O
10%	O
of	O
the	O
email	O
addresses	O
of	O
a	O
set	O
of	O
forum	O
users	O
could	O
be	O
determined	O
from	O
the	O
Gravatar	B-General_Concept
URLs	O
combined	O
with	O
the	O
forum	O
user	O
names	O
.	O
</s>
<s>
Subsequently	O
,	O
in	O
2013	O
,	O
security	O
researcher	O
Dominique	O
Bongard	O
presented	O
that	O
he	O
was	O
able	O
to	O
determine	O
45%	O
of	O
the	O
email	O
addresses	O
used	O
to	O
post	O
comments	O
on	O
a	O
well-known	O
French	O
political	O
forum	O
by	O
using	O
Gravatar	B-General_Concept
URLs	O
and	O
the	O
open	O
source	O
Hashcat	B-Application
password	I-Application
cracking	I-Application
tool	I-Application
.	O
</s>
<s>
Given	O
that	O
Hashcat	B-Application
uses	O
graphics	B-Architecture
processing	I-Architecture
units	I-Architecture
to	O
achieve	O
high-efficiencies	O
at	O
cracking	O
hashes	B-Error_Name
,	O
it	O
has	O
been	O
proposed	O
that	O
as	O
GPU	B-Architecture
technology	O
and	O
performance	O
continues	O
to	O
improve	O
,	O
that	O
Gravatar	B-General_Concept
hashes	B-Error_Name
will	O
only	O
become	O
easier	O
to	O
crack	O
over	O
time	O
as	O
a	O
result	O
.	O
</s>
<s>
This	O
is	O
in	O
addition	O
to	O
the	O
fact	O
that	O
the	O
MD5	B-Algorithm
hashing	B-Error_Name
algorithm	I-Error_Name
itself	O
is	O
severely	O
compromised	O
and	O
unfit	O
for	O
cryptographic	O
applications	O
;	O
the	O
CMU	O
Software	O
Engineering	O
Institute	O
has	O
recommended	O
against	O
its	O
use	O
in	O
any	O
capacity	O
since	O
the	O
end	O
of	O
2008	O
.	O
</s>
<s>
In	O
October	O
2020	O
,	O
a	O
technique	O
for	O
scraping	O
large	O
volumes	O
of	O
data	O
from	O
Gravatar	B-General_Concept
was	O
exposed	O
by	O
Carlo	O
di	O
Dato	O
,	O
a	O
security	O
researcher	O
,	O
after	O
being	O
ignored	O
by	O
Gravatar	B-General_Concept
when	O
he	O
raised	O
his	O
concerns	O
with	O
them	O
.	O
</s>
<s>
167	O
million	O
names	O
,	O
usernames	O
and	O
MD5	B-Algorithm
hashes	I-Algorithm
of	O
email	O
addresses	O
used	O
to	O
reference	O
users	O
 '	O
avatars	B-Application
were	O
subsequently	O
scraped	O
and	O
distributed	O
within	O
the	O
hacking	O
community	O
.	O
</s>
<s>
114	O
million	O
of	O
the	O
MD5	B-Algorithm
hashes	I-Algorithm
were	O
cracked	O
and	O
distributed	O
alongside	O
the	O
source	O
hash	B-Error_Name
,	O
thus	O
disclosing	O
the	O
original	O
email	O
address	O
and	O
accompanying	O
data	O
,	O
with	O
email	O
account	O
holders	O
able	O
to	O
check	O
whether	O
their	O
addresses	O
have	O
been	O
leaked	O
using	O
Have	O
I	O
Been	O
Pwned	O
.	O
</s>
