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lib/Crypt/DSA/Util.pm  view on Meta::CPAN

    my $one = $n - $n1;  # not just 1, but a bigint
    my $witness = $one * 100;

    # find the power of two for the top bit of $n1
    my $p2 = $one;
    my $p2index = -1;
    ++$p2index, $p2 *= 2
	while $p2 <= $n1;
    $p2 /= 2;

    # number of iterations:  5 for 260-bit numbers, go up to 25 for smaller
    my $last_witness = 5;
    $last_witness += (260 - $p2index) / 13 if $p2index < 260;

    for my $witness_count (1..$last_witness) {
	$witness *= 1024;
	$witness += int(rand(1024));  # XXXX use good rand
	$witness = $witness % $n if $witness > $n;
	$witness = $one * 100, redo if $witness == 0;

	my $prod = $one;