.TH ZMODPOW 3 libzahl
.SH NAME
zmodpow - Calculate a modular power of a big integer
.SH SYNOPSIS
.nf
#include <zahl.h>

void zmodpow(z_t \fIpower\fP, z_t \fIbase\fP, z_t \fIexponent\fP, z_t \fImodulator\fP);
.fi
.SH DESCRIPTION
.B zmodpow
calculates the
.IR exponent :th
power of a
.IR base ,
modulus a
.IR modulator ,
and stores the result in
.IR power .
That is,
.I power
gets
.RI ( base
↑
.IR exponent )
Mod
.IR modulator .
.P
It is safe to call
.B zmodpow
with non-unique parameters.
.P
See
.BR zmod (3)
for details on modulation.
.SH RATIONALE
It is possible to calculate the modular power
with a faster algorithm than calculating the
power and than the modulus of that power.
.SH SEE ALSO
.BR zmodpowu (3),
.BR zmodsqr (3),
.BR zmodmul (3),
.BR zsqr (3),
.BR zstr (3),
.BR zadd (3),
.BR zsub (3),
.BR zmul (3),
.BR zdiv (3),
.BR zmod (3),
.BR zneg (3),
.BR zabs (3)