<s>
The	O
Message	B-Algorithm
Authenticator	I-Algorithm
Algorithm	I-Algorithm
(	O
MAA	O
)	O
was	O
one	O
of	O
the	O
first	O
cryptographic	O
functions	O
for	O
computing	O
a	O
message	B-Algorithm
authentication	I-Algorithm
code	I-Algorithm
(	O
MAC	O
)	O
.	O
</s>
<s>
The	O
MAA	O
was	O
one	O
of	O
the	O
first	O
Message	B-Algorithm
Authentication	I-Algorithm
Code	I-Algorithm
algorithms	O
to	O
gain	O
widespread	O
acceptance	O
.	O
</s>
<s>
The	O
original	O
specification	O
of	O
the	O
MAA	O
was	O
given	O
in	O
a	O
combination	O
of	O
natural	O
language	O
and	O
tables	O
,	O
complemented	O
by	O
two	O
implementations	O
in	O
C	B-Language
and	O
BASIC	O
programming	O
languages	O
.	O
</s>
<s>
The	O
MAA	O
was	O
adopted	O
by	O
ISO	B-General_Concept
in	O
1987	O
and	O
became	O
part	O
of	O
international	O
standards	O
ISO	B-General_Concept
8730	O
and	O
ISO	B-General_Concept
8731-2	O
intended	O
to	O
secure	O
the	O
authenticity	O
and	O
integrity	O
of	O
banking	O
transactions	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
MAA	O
was	O
withdrawn	O
from	O
ISO	B-General_Concept
standards	O
in	O
2002	O
but	O
continued	O
to	O
be	O
used	O
as	O
a	O
prominent	O
case	O
study	O
for	O
assessing	O
various	O
formal	B-Architecture
methods	I-Architecture
.	O
</s>
<s>
The	O
MAA	O
has	O
been	O
used	O
as	O
a	O
prominent	O
case	O
study	O
for	O
assessing	O
various	O
formal	B-Architecture
methods	I-Architecture
.	O
</s>
<s>
In	O
the	O
early	O
1990s	O
,	O
the	O
NPL	O
developed	O
three	O
formal	O
specifications	O
of	O
the	O
MAA	O
:	O
one	O
in	O
Z	B-Language
,	O
one	O
in	O
LOTOS	B-Application
,	O
and	O
one	O
in	O
VDM	B-Application
.	O
</s>
<s>
The	O
VDM	B-Application
specification	O
became	O
part	O
of	O
the	O
1992	O
revision	O
of	O
the	O
International	O
Standard	O
8731-2	O
,	O
and	O
three	O
implementations	O
were	O
manually	O
derived	O
from	O
that	O
latter	O
specification	O
:	O
C	B-Language
,	O
Miranda	B-Language
,	O
and	O
Modula-2	B-Language
.	O
</s>
<s>
In	O
2018	O
,	O
two	O
new	O
formal	O
specifications	O
of	O
the	O
MAA	O
,	O
in	O
LOTOS	B-Application
and	O
LNT	O
,	O
have	O
been	O
published	O
.	O
</s>
