January 8, 2002
Practical Aspects of Modern Cryptography
How to compute
Y
X
mod N
•
Exponentiation by Repeated Squaring
•
•
To compute
Y
X
,
•
compute
Y
,
Y
2
,
Y
4
,
Y
8
,
Y
16
, …
•
and multiply those values dictated by the binary
representation of
X
.
•
•
Example
:
Y
26
=
Y
2
•
Y
8
•
Y
16
.