<s>
The	O
MD4	B-Algorithm
Message-Digest	B-Algorithm
Algorithm	I-Algorithm
is	O
a	O
cryptographic	B-Algorithm
hash	I-Algorithm
function	I-Algorithm
developed	O
by	O
Ronald	O
Rivest	O
in	O
1990	O
.	O
</s>
<s>
The	O
algorithm	O
has	O
influenced	O
later	O
designs	O
,	O
such	O
as	O
the	O
MD5	B-Algorithm
,	O
SHA-1	B-Algorithm
and	O
RIPEMD	B-Algorithm
algorithms	O
.	O
</s>
<s>
The	O
initialism	O
"	O
MD	O
"	O
stands	O
for	O
"	O
Message	B-Algorithm
Digest	I-Algorithm
"	O
.	O
</s>
<s>
The	O
security	O
of	O
MD4	B-Algorithm
has	O
been	O
severely	O
compromised	O
.	O
</s>
<s>
The	O
first	O
full	O
collision	B-Algorithm
attack	I-Algorithm
against	O
MD4	B-Algorithm
was	O
published	O
in	O
1995	O
,	O
and	O
several	O
newer	O
attacks	O
have	O
been	O
published	O
since	O
then	O
.	O
</s>
<s>
As	O
of	O
2007	O
,	O
an	O
attack	O
can	O
generate	O
collisions	O
in	O
less	O
than	O
2	O
MD4	B-Algorithm
hash	I-Algorithm
operations	O
.	O
</s>
<s>
A	O
variant	O
of	O
MD4	B-Algorithm
is	O
used	O
in	O
the	O
ed2k	B-Protocol
URI	I-Protocol
scheme	I-Protocol
to	O
provide	O
a	O
unique	O
identifier	O
for	O
a	O
file	O
in	O
the	O
popular	O
eDonkey2000	O
/	O
eMule	O
P2P	O
networks	O
.	O
</s>
<s>
MD4	B-Algorithm
was	O
also	O
used	O
by	O
the	O
rsync	B-Application
protocol	O
(	O
prior	O
to	O
version	O
3.0.0	O
)	O
.	O
</s>
<s>
MD4	B-Algorithm
is	O
used	O
to	O
compute	O
NTLM	O
password-derived	O
key	O
digests	O
on	O
Microsoft	O
Windows	O
NT	O
,	O
XP	O
,	O
Vista	O
,	O
7	O
,	O
8	O
,	O
and	O
10	O
.	O
</s>
<s>
Weaknesses	O
in	O
MD4	B-Algorithm
were	O
demonstrated	O
by	O
Den	O
Boer	O
and	O
Bosselaers	O
in	O
a	O
paper	O
published	O
in	O
1991	O
.	O
</s>
<s>
The	O
first	O
full-round	O
MD4	B-Algorithm
collision	B-Algorithm
attack	I-Algorithm
was	O
found	O
by	O
Hans	O
Dobbertin	O
in	O
1995	O
,	O
which	O
took	O
only	O
seconds	O
to	O
carry	O
out	O
at	O
that	O
time	O
.	O
</s>
<s>
found	O
a	O
very	O
efficient	O
collision	B-Algorithm
attack	I-Algorithm
,	O
alongside	O
attacks	O
on	O
later	O
hash	B-Algorithm
function	I-Algorithm
designs	O
in	O
the	O
MD4/MD5/SHA-1/RIPEMD	O
family	O
.	O
</s>
<s>
In	O
2008	O
,	O
the	O
preimage	O
resistance	O
of	O
MD4	B-Algorithm
was	O
also	O
broken	O
by	O
Gaëtan	O
Leurent	O
,	O
with	O
a	O
2102	O
attack	O
.	O
</s>
<s>
In	O
2011	O
,	O
RFC	O
6150	O
stated	O
that	O
RFC	O
1320	O
(	O
MD4	B-Algorithm
)	O
is	O
historic	O
(	O
obsolete	O
)	O
.	O
</s>
<s>
The	O
128-bit	O
(	O
16-byte	O
)	O
MD4	B-Algorithm
hashes	I-Algorithm
(	O
also	O
termed	O
message	B-Algorithm
digests	I-Algorithm
)	O
are	O
typically	O
represented	O
as	O
32-digit	O
hexadecimal	O
numbers	O
.	O
</s>
<s>
The	O
following	O
demonstrates	O
a	O
43-byte	O
ASCII	B-Protocol
input	O
and	O
the	O
corresponding	O
MD4	B-Algorithm
hash	I-Algorithm
:	O
</s>
<s>
Even	O
a	O
small	O
change	O
in	O
the	O
message	O
will	O
(	O
with	O
overwhelming	O
probability	O
)	O
result	O
in	O
a	O
completely	O
different	O
hash	B-Algorithm
,	O
e.g.	O
</s>
<s>
The	O
hash	B-Algorithm
of	O
the	O
zero-length	O
string	O
is	O
:	O
</s>
