<s>
KCDSA	B-Algorithm
(	O
Korean	O
Certificate-based	O
Digital	O
Signature	O
Algorithm	O
)	O
is	O
a	O
digital	O
signature	O
algorithm	O
created	O
by	O
a	O
team	O
led	O
by	O
the	O
Korea	O
Internet	O
&	O
Security	O
Agency	O
(	O
KISA	O
)	O
.	O
</s>
<s>
It	O
is	O
an	O
ElGamal	B-Algorithm
variant	O
,	O
similar	O
to	O
the	O
Digital	O
Signature	O
Algorithm	O
and	O
GOST	O
R	O
34.10-94	O
.	O
</s>
<s>
The	O
standard	O
algorithm	O
is	O
implemented	O
over	O
,	O
but	O
an	O
elliptic	O
curve	O
variant	O
(	O
EC-KCDSA	B-Algorithm
)	O
is	O
also	O
specified	O
.	O
</s>
<s>
KCDSA	B-Algorithm
requires	O
a	O
collision-resistant	O
cryptographic	B-Algorithm
hash	I-Algorithm
function	I-Algorithm
that	O
can	O
produce	O
a	O
variable-sized	O
output	O
(	O
from	O
128	O
to	O
256	O
bits	O
,	O
in	O
32-bit	O
increments	O
)	O
.	O
</s>
<s>
HAS-160	B-Algorithm
,	O
another	O
Korean	O
standard	O
,	O
is	O
the	O
suggested	O
choice	O
.	O
</s>
<s>
:	O
a	O
hash-value	O
of	O
Cert	O
Data	O
,	O
i.e.	O
,	O
.	O
</s>
<s>
In	O
the	O
revised	O
spec	O
,	O
z	O
is	O
defined	O
as	O
being	O
the	O
bottom	O
B	O
bits	O
of	O
the	O
public	O
key	O
y	O
,	O
where	O
B	O
is	O
the	O
block	O
size	O
of	O
the	O
hash	B-Algorithm
function	I-Algorithm
in	O
bits	O
(	O
typically	O
512	O
or	O
1024	O
)	O
.	O
</s>
<s>
:	O
a	O
collision	O
resistant	O
hash	B-Algorithm
function	I-Algorithm
with	O
|q|	O
-bit	O
digests	O
.	O
</s>
<s>
The	O
specification	O
is	O
vague	O
about	O
how	O
the	O
integer	O
be	O
reinterpreted	O
as	O
a	O
byte	O
string	O
input	O
to	O
hash	B-Algorithm
function	I-Algorithm
.	O
</s>
<s>
EC-KCDSA	B-Algorithm
is	O
essentially	O
the	O
same	O
algorithm	O
using	O
Elliptic-curve	O
cryptography	O
instead	O
of	O
discrete	O
log	O
cryptography	O
.	O
</s>
<s>
The	O
user	O
parameters	O
and	O
algorithms	O
are	O
essentially	O
the	O
same	O
as	O
for	O
discrete	O
log	O
KCDSA	B-Algorithm
except	O
that	O
modular	O
exponentiation	O
is	O
replaced	O
by	O
point	O
multiplication	O
.	O
</s>
