File Coverage

blib/lib/Crypt/SHAVS.pm

Criterion	Covered	Total	%
statement	44	44	100.0
branch	16	18	88.8
condition			n/a
subroutine	7	7	100.0
pod	2	2	100.0
total	69	71	97.1

package Crypt::SHAVS;

use strict;
use vars qw($VERSION);

$VERSION   = 0.02;

sub new {
	my ($class, $SHA, $BIT) = @_;

	my $self = {};
	$self->{SHA} = $SHA;
	$self->{BIT} = $BIT;
	bless($self, $class);
}

sub _SHA {
	my $self = shift;

	pop unless $self->{BIT};
	&{$self->{SHA}}(@_);
}

sub _computeMsg {
	my ($self, $values) = @_;

	my $Msg2bin = pack("H*", $values->{Msg});
	my $nbits  = $values->{Len};
	my $nbytes = $nbits >> 3;
	if ($nbits % 8) { $nbytes++ }
	$Msg2bin = substr($Msg2bin, 0, $nbytes)
			if $nbytes < length($Msg2bin);

	unpack("H*", $self->_SHA($Msg2bin, $nbits));
}

sub _computeMonte {
	my ($self, $values) = @_;

	die "COUNT value out of sequence: $values->{COUNT}\n"
		if $values->{count}++ != $values->{COUNT};
	my ($MD0, $MD1, $MD2, $MDi) = (pack("H*", $values->{Seed})) x 3;
	for (1..1000) {
		my $M = $MD0 . $MD1 . $MD2;
		$MDi = $self->_SHA($M, length($M)*8);
		($MD0, $MD1, $MD2) = ($MD1, $MD2, $MDi);
	}
	$values->{Seed} = unpack("H*", $MDi);
}

my $TAGS = join('|', qw(Len Msg MD Seed COUNT));

sub check {
	my ($self, $file) = @_;

	local $_;
	local *F;
	open(F, $file) or die $!;

	my $values = { 'count' => 0 };
	while () {
		next unless /^\s*($TAGS)\s*=\s*([\da-f]+)/o;
		$values->{$1} = $2;
		next unless $1 eq 'MD';
		my $computed = defined $values->{Msg}
			? $self->_computeMsg($values)
			: $self->_computeMonte($values);
		my $ok = $computed eq $values->{MD};
		print "$computed ", $ok ? "OK" : "FAILED", "\n";
	}
	close(F);
}

1;
__END__