#!/afs/athena/contrib/perl/perl

#	By Matthew K. Gray
#	   mkgray@athena.mit.edu
#	   January, 1993

$|=1;
$times = 4;

&load_dict("/afs/sipb/user/mkgray/words");

sub load_dict{
$dict = @_;
print("Loading dictionary...\n");
open(DI, $dict);
while(<DI>){
	chop;
	if(/^\w+$/){
		if(length ==2){push(@flist2,$_);
#			print("Adding: $_\n");
}
		elsif(length ==3){push(@flist3,$_);
#			print("Adding: $_\n");
}
		elsif(length ==4){push(@flist4,$_);
#			print("Adding: $_\n");
}
		elsif(length ==5){push(@flist5,$_);
			}
		elsif(length ==6){push(@flist6,$_);
			}
		elsif(length ==7){push(@flist7,$_);
			}
		elsif(length ==8){push(@flist8,$_);
			}
		elsif(length ==9){push(@flit9,$_);
			}
	if(length((flist2)%10)==0){print(".");}
}
}
print("Loaded.\n");

$codefile = shift(@ARGV);
if(!$codefile){
print("Where is the ciphertext?\n");
$codefile = <STDIN>;
chop($codefile);}
open (FI, "$codefile") || die "No code file";

@cipher = ('a'..'z');

print("Getting frequencies...\n");
while (<FI>) {
		tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
		$ctext .= $_;
		foreach $x (0..25) {
		while(/$cipher[$x]/g){
		$noc{$cipher[$x]}++;
		}
		}
}
close(FI);
print("Got em.\n");

#for($x=0;$x<=25;$x++) 
{
#print("$noc{$cipher[$x]} $cipher[$x], ");
}
#print("Sorting...");
@toplets = sort byfreq keys %noc;
#print("done.\n");
#print("Top 5 characters:\n");
#print("$toplets[0], $toplets[1], $toplets[2], $toplets[3], $toplets[4]\n");
#print("\nOk.  Let's try substituting E for $toplets[0] and T for either $toplets[1] or $toplets[2] or $toplets[3]\n");

#print("First, let's see if we can find any THE's.\n");
while($ctext =~/ ..$toplets[0] /g){
	$w = $&;
	$w =~ s/ //g;
	$thea{$w}++;
	@thes = sort byvalue keys %thea;
}
print("$thes[0] == THE.\n");
@thel = split(//, $thes[0]);
$ntext1 = $ctext;
$ntext1 =~ s/$toplets[0]/E/g;
$e = $toplets[0];
$ntext1 =~ s/$thel[1]/H/g;
$h = $thel[1];
$ntext1 =~ s/$thel[0]/T/g;
$t = $thel[0];
$cracked = 3;
$ntext2 = $ctext;

#print("Ok, now we are guessing at some two letter words...\n");

while($ctext =~/ .. /g){
	$w = $&;
	$w =~ s/ //g;
	$twoa{$w}++;
	@twos = sort byvaluet keys %twoa;
}
foreach $tw (@twos){
	if($tw=~/$t./){$tw =~ s/$t//; $o = $tw; $to =1;}
	last if $to;
}
if($o){
print("$o == O.\n");
$cracked++;
$ntext1 =~ s/$o/O/g;
foreach $tw (@twos){
	if($tw=~/$o./){$tw =~ s/$o//; $f = $tw; $of =1;}
	last if $of;
}
if($f){
	print("$f == F.\n");
$ntext1 =~ s/$f/F/g;
$cracked++;}}

#print("Ok, at this point we do the hi-frequency word attack.\n");
foreach $lkewsfj (0..5){	#learn more


#  ************ Two letter words *************
#print("Starting with two letter words...\n");
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/ \w\w /g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
	if(grep(/$search/, @flist2) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist2);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		#print("Aha!  $match[0] is $word.\n");
		foreach $cnt (0..$#lets){
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist2 = grep(!/$match[0]/i,@flist2);
	}
}
}

#print("...three letter words...\n");
%ntwoa=();
@ntwos=();
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/ \w\w\w /g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;

	if(grep(/$search/, @flist3) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist3);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		#print("Aha!  $word is $match[0].\n");
		foreach $cnt (0..$#lets){
		print("$lets[$cnt] == $clets[$cnt]\n");
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist3 = grep(!/$match[0]/i,@flist3);
	}
}
}

##print("...four letter words...\n");
%ntwoa=();
@ntwos=();
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/ \w\w\w\w /g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
	if(grep(/$search/, @flist4) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist4);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		#print("Aha!  $word is $match[0].\n");
		foreach $cnt (0..$#lets){
		print("$lets[$cnt] == $clets[$cnt]\n");
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist4 = grep(!/$match[0]/i,@flist4);
	}
}
}

##print("...five letter words...\n");
%ntwoa=();
@ntwos=();
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/ \w\w\w\w\w /g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
	if(grep(/$search/, @flist5) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist5);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		#print("Aha!  $word is $match[0].\n");
		foreach $cnt (0..$#lets){
		print("$lets[$cnt] == $clets[$cnt]\n");
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist5 = grep(!/$match[0]/i,@flist5);
	}
}
}

##print("...six letter words...\n");
%ntwoa=();
@ntwos=();
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/ \w\w\w\w\w\w /g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
	if(grep(/$search/, @flist6) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist6);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		#print("Aha!  $word is $match[0].\n");
		foreach $cnt (0..$#lets){
		print("$lets[$cnt] == $clets[$cnt]\n");
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist6 = grep(!/$match[0]/i,@flist6);
	}
}
}


##print("...seven letter words...\n");
%ntwoa=();
@ntwos=();
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/\W\w\w\w\w\w\w\w\W/g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
	if(grep(/$search/, @flist7) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist7);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		#print("Aha!  $word is $match[0].\n");
		foreach $cnt (0..$#lets){
		print("$lets[$cnt] == $clets[$cnt]\n");
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist7 = grep(!/$match[0]/i,@flist7);
	}
}
}

##print("...eight letter words...\n");
%ntwoa=();
@ntwos=();
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/\W\w\w\w\w\w\w\w\w\W/g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
	if(grep(/$search/, @flist8) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist8);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		#print("Aha!  $word is $match[0].\n");
		foreach $cnt (0..$#lets){
		print("$lets[$cnt] == $clets[$cnt]\n");
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist8 = grep(!/$match[0]/i,@flist8);
	}
}
}

##print("...nine letter words...\n");
%ntwoa=();
@ntwos=();
foreach $nothing (0..$times){	#do five times to make progress
while($ntext1 =~/\W\w\w\w\w\w\w\w\w\w\W/g){
	$w = $&;
	$w =~ s/ //g;
	$ntwoa{$w}++;
	@ntwos = sort byvaluetn keys %ntwoa;
}
foreach $tn (0.. $#ntwos/3){
	$word = $ntwos[$tn];
	$search = $word;
	$search =~ s/[a-z]/\./g;
	$search =~ tr/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/;
	if(grep(/$search/, @flist9) == 1){
		@lets = split(//, $word);
		@match = grep(/$search/, @flist9);
		$match[0] =~ tr/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
		@clets = split(//, $match[0]);
		foreach $cnt (0..$#lets){
		print("$lets[$cnt] == $clets[$cnt]\n");
		$ntext1 =~ s/$lets[$cnt]/$clets[$cnt]/g;}
		@flist9 = grep(!/$match[0]/i,@flist9);
	}
}
}



}
print("Final:\n$ntext1\n");
$ntext1 =~ y/a-z/_/;
print("With blanks:\n$ntext1\n");

sub byvaluet{
	$twoa{$b} <=> $twoa{$a};
}

sub byvaluetn{
	$ntwoa{$b} <=> $ntwoa{$a};
}
sub byvalue {
	$thea{$b} <=> $thea{$a};
}

sub byfreq {

	$noc{$b} <=> $noc{$a};
}