Abstract: A digital message M is transformed by means
of an operation to modulo-N exponentiate
M by a number e all these numbers being large-length
integers, having n bits, which uses a sequence
of two successive operations, the first in
the form of:
B.sub.i =a.sub.i.X+T.2.sup.m where B.sub.i
and X are calculation variables, where a.sub.i
is an extract of m bits of a second calculation
variable A whose value results from a previous
operation, which extract is taken in the
decreasing order of weight of A, of rank
i, and where T is a summing variable used
for the calculation of the variable A, and
the second operation consists of reducing
the length of the variable B.sub.i. (中略)
