package Digest::Perl::MD4;

use strict;
use Exporter;
use warnings;
use vars qw($VERSION @ISA @EXPORTER @EXPORT_OK);

@EXPORT_OK = qw(md4 md4_hex md4_base64);

@ISA = 'Exporter';
$VERSION = '1.3';

# Module logic and interface adapted from Digest::Perl::MD5 v1.5 from CPAN.
# See author information below.

# The MD4 logic Perl code has these origins:
#     MD5[0] in 8 lines of perl5
#
#     The MD5 algorithm (Message Digest 5) is a cryptographic message digest
#     algorithm.  It is the message digest algorithm used by PGP 2.x.
#
#     MD5 was designed by Ron Rivest[1], who is also the `R' in `RSA'.  MD5 is
#     described in rfc1321[2].  C source code is included with the RFC.
#
#     John Allen[3] wrote this implementation of MD5 optimised for size, in 8
#     lines of perl5:
{
    no warnings;
<<'EOF';				# quote this stuff
#!/bin/perl -iH9T4C`>_-JXF8NMS^$#)4=@<,$18%"0X4!`L0%P8*#Q4``04``04#!P`` ~JLA
@A=unpack N4C24,unpack u,$^I;@K=map{int abs 2**32*sin$_}1..64;sub L{($x=pop)
<<($n=pop)|2**$n-1&$x>>32-$n}sub M{($x=pop)-($m=1+~0)*int$x/$m}do{$l+=$r=read
STDIN,$_,64;$r++,$_.="\x80"if$r<64&&!$p++;@W=unpack V16,$_."\0"x7;$W[14]=$l*8
if$r<57;($a,$b,$c,$d)=@A;for(0..63){$a=M$b+L$A[4+4*($_>>4)+$_%4],M&{(sub{$b&$c
|$d&~$b},sub{$b&$d|$c&~$d},sub{$b^$c^$d},sub{$c^($b|~$d)})[$z=$_/16]}+$W[($A[
20+$z]+$A[24+$z]*($_%16))%16]+$K[$_]+$a;($a,$b,$c,$d)=($d,$a,$b,$c)}$v=a;for(
@A[0..3]){$_=M$_+${$v++}}}while$r>56;print unpack H32,pack V4,@A # RSA's MD5
EOF
}

#     Comments, html bugs to Adam Back[5] at adam@cypherspace.org.

# My MD4 modifications are based on reading rfc1320.txt[6].  While some
# remnants of the the highly concise nature of the orginal remain, I've made
# numerous typographical adjustments. -ota

# [0] http://www.cypherspace.org/~adam/rsa/md5.html
# [1] http://theory.lcs.mit.edu/~rivest/homepage.html
# [2] http://www.ietf.org/rfc/rfc1321.txt
# [3] mailto:allen@grumman.com
# [4] http://www.cypherspace.org/~adam/rsa/sha.html
# [5] http://www.cypherspace.org/~adam/
# [6] http://www.ietf.org/rfc/rfc1320.txt

# object part of this module
sub new {
	my $class = shift;
	bless {}, ref($class) || $class;
}

sub reset {
	my $self = shift;
	delete $self->{data};
	$self
}

sub add(@) {
	my $self = shift;
	$self->{data} .= join'', @_;
	$self
}

sub addfile {
  	my ($self,$fh) = @_;
	if (!ref($fh) && ref(\$fh) ne "GLOB") {
	    require Symbol;
	    $fh = Symbol::qualify($fh, scalar caller);
	}
	$self->{data} .= do{local$/;<$fh>};
	$self
}

sub digest {
	md4(shift->{data})
}

sub hexdigest {
	md4_hex(shift->{data})
}

sub b64digest {
	md4_base64(shift->{data})
}

# This is the actual MD4 algorithm

sub L # left-rotate
{
    my ($n, $x) = @_;
    $x<<$n|2**$n-1&$x>>32-$n;
}

sub M # mod 2**32
{
    my ($x) = @_;
    my $m = 1+~0;
    $x-$m*int$x/$m;
}

sub R # reverse two bit number
{
    my $n = pop;
    ($n&1)*2 + ($n&2)/2;
}

sub md4(@)
{
    my @input = grep defined && length>0, split /(.{64})/, join '', @_;
    push @input, '' if !@input || length($input[$#input]) >= 56;
    my @A = (0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476); # initial regs
    my @L = qw(3 7 11 19 3 5 9 13 3 9 11 15); # left rotate counts
    my @O = (1, 4, 4,			# x stride for input index
	     4, 1, 1,			# y stride for input index
	     0, 0, 1);			# bitwise reverse both indexes
    my @I = map {my $z=int $_/16;my $x=$_%4; my $y=int $_%16/4;
		 $O[6+$z]&&(($x,$y)=(R($x),R($y)));
		 $O[$z]*$x+$O[3+$z]*$y} 0..47;
    my @T = (0, 0x5A827999, 0x6ED9EBA1);

    my $l = 0;
    my $p = 0;
    my ($a,$b,$c,$d);
    foreach (@input) {
	my $r=length($_);
	$l+=$r;
	$r++,$_.="\x80" if $r<64&&!$p++;
	my @W=unpack 'V16',$_."\0"x7;
	push @W, (0)x16 if @W<16;
	$W[14]=$l*8 if $r<57;		# add bit-length in low 32-bits
	($a,$b,$c,$d) = @A;
	for (0..47) {
	    my $z = int $_/16;
	    $a=L($L[4*($_>>4)+$_%4],
		 M(&{(sub{$b&$c|~$b&$d}, 	# F
		      sub{$b&$c|$b&$d|$c&$d},	# G
		      sub{$b^$c^$d}		# H
		     )[$z]}
		   +$a+$W[$I[$_]]+$T[$z]));
	    ($a,$b,$c,$d)=($d,$a,$b,$c);
	}
	my @v=($a, $b, $c, $d);
	for (0..3) {
	    $A[$_] = M($A[$_]+$v[$_]);
	}
    }
    pack 'V4', @A;
}

sub md4_hex(@) {
  unpack 'H*', &md4;
}

sub md4_base64(@) {
  encode_base64(&md4);
}


sub encode_base64 ($) {
    my $res;
    while ($_[0] =~ /(.{1,45})/gs) {
	$res .= substr pack('u', $1), 1;
	chop $res;
    }
    $res =~ tr|` -_|AA-Za-z0-9+/|;#`
    chop $res;chop $res;
    $res;
}

1;

=head1 NAME

Digest::Perl::MD4 - Perl implementation of Ron Rivests MD4 Algorithm

=head1 DISCLAIMER

This is B<not> C-code interface (like C<Digest::MD5>) but a Perl-only
implementation of MD4 (like C<Digest::Perl::MD5>).  Because of this, it is
B<slow> but avoids platform specific complications.  For efficiency you should
use C<Digest::MD4> instead of this module if it is available.

=head1 SYNOPSIS

 # Functional style
 use Digest::Perl::MD4 qw(md4 md4_hex md4_base64);

 $hash = md4 $data;
 $hash = md4_hex $data;
 $hash = md4_base64 $data;


 # OO style
 use Digest::Perl::MD4;

 $ctx = Digest::Perl::MD4->new;

 $ctx->add($data);
 $ctx->addfile(*FILE);

 $digest = $ctx->digest;
 $digest = $ctx->hexdigest;
 $digest = $ctx->b64digest;

=head1 DESCRIPTION

This modules has the same interface as C<Digest::MD5>.  It should be compatible
 with the Digest::MD4 module written by Mike McCauley <mikem@open.com.au>.

=head1 EXAMPLES

The simplest way to use this library is to import the md4_hex() function (or
one of its cousins):

    use Digest::Perl::MD4 'md4_hex';
    print 'Digest is ', md4_hex('foobarbaz'), "\n";

The above example would print out the message

    Digest is b2b2b528f632f554ae9cb2c02c904eeb

provided that the implementation is working correctly.  The same checksum can
also be calculated in OO style:

    use Digest::Perl::MD4;

    $md4 = Digest::Perl::MD4->new;
    $md4->add('foo', 'bar');
    $md4->add('baz');
    $digest = $md4->hexdigest;

    print "Digest is $digest\n";

=head1 LIMITATIONS

This implementation of the MD4 algorithm has some limitations:

=over 4

=item

It is slow, very slow, but still useful for encrypting small amounts of data
like passwords.

=item

You can only encrypt up to 2^32 bits = 512 MB on 32bit archs.

=item

C<Digest::Perl::MD4> loads all data to encrypt into memory. This is a todo.

=back

=head1 SEE ALSO

L<Digest::MD5>

RFC 1320

=head1 COPYRIGHT

This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

 Copyright 2002 Ted Anderson.
 Copyright 2000 Christian Lackas, Imperia Software Solutions.
 Copyright 1998-1999 Gisle Aas.
 Copyright 1995-1996 Neil Winton.
 Copyright 1991-1992 RSA Data Security, Inc.

The MD4 algorithm is defined in RFC 1320. The basic C code
implementing the algorithm is derived from that in the RFC and is
covered by the following copyright:

=over 4

=item

Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
rights reserved.

License to copy and use this software is granted provided that it
is identified as the "RSA Data Security, Inc. MD4 Message-Digest
Algorithm" in all material mentioning or referencing this software
or this function.

License is also granted to make and use derivative works provided
that such works are identified as "derived from the RSA Data
Security, Inc. MD4 Message-Digest Algorithm" in all material
mentioning or referencing the derived work.

RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.

These notices must be retained in any copies of any part of this
documentation and/or software.

=back

This copyright does not prohibit distribution of any version of Perl
containing this extension under the terms of the GNU or Artistic
licenses.

=head1 AUTHORS

The original MD5 interface was written by Neil Winton
<N.Winton@axion.bt.co.uk>.

C<Digest::MD5> was made by Gisle Aas <gisle@aas.no>.

C<Digest::Perl::MD5> was made by Christian Lackas <delta@clackas.de>.

MD5 in 8 lines of perl5 implemented and optimized for size by John Allen[3] and
collected by Adam Back[5] <adam@cypherspace.org>.  Conversion to MD4 algorithm
by Ted Anderson <ota@transarc.com>.

=head1 Footnotes

=over 4

=item [3]

L<allen@grumman.com>

=item [5]

L<http://www.cypherspace.org/~adam/>

=back

=cut