|
=={{header|Perl}}==
<lang Perlperl>use strict;
use strict;
use warnings;
use Getopt::Longfeature 'say';
my $max_key_lengths = 5; # number of keylengths to try
my $MAXKEYLENGTHS=5;
#specify how many keylengths to try
#will pick the most probable (up to $MAXKEYLENGTHS) keys
#and decrypt the message
sub myguess {
my $ciphertext="
my ($text) = (@_);
MOMUD EKAPV TQEFM OEVHP AJMII CDCTI FGYAG JSPXY ALUYM NSMYH
my ($seqtext, $i, @guesses_ranked, @spacing, @factors, @sortedfactors, $pos, %freq, %Keys);
VUXJE LEPXJ FXGCM JHKDZ RYICU HYPUS PGIGM OIYHF WHTCQ KMLRD
ITLXZ LJFVQ GHOLW CUHLO MDSOE KTALU VYLNZ RFGBX PHVGA LWQIS
FGRPH JOOFW GUBYI LAPLA LCAFA AMKLG CETDW VOELJ IKGJB XPHVG
ALWQC SNWBU BYHCU HKOCE XJEYK BQKVY KIIEH GRLGH XEOLW AWFOJ
ILOVV RHPKD WIHKN ATUHN VRYAQ DIVHX FHRZV QWMWV LGSHN NLVZS
JLAKI FHXUF XJLXM TBLQV RXXHR FZXGV LRAJI EXPRV OSMNP KEPDT
LPRWM JAZPK LQUZA ALGZX GVLKL GJTUI ITDSU REZXJ ERXZS HMPST
MTEOE PAPJH SMFNB YVQUZ AALGA YDNMP AQOWT UHDBV TSMUE UIMVH
QGVRW AEFSP EMPVE PKXZY WLKJA GWALT VYYOB YIXOK IHPDS EVLEV
RVSGB JOGYW FHKBL GLXYA MVKIS KIEHY IMAPX UOISK PVAGN MZHPW
TTZPV XFCCD TUHJH WLAPF YULTB UXJLN SIJVV YOVDJ SOLXG TGRVO
SFRII CTMKO JFCQF KTINQ BWVHG TENLH HOGCS PSFPV GJOKM SIFPR
ZPAAS ATPTZ FTPPD PORRF TAXZP KALQA WMIUD BWNCT LEFKO ZQDLX
BUXJL ASIMR PNMBF ZCYLV WAPVF QRHZV ZGZEF KBYIO OFXYE VOWGB
BXVCB XBAWG LQKCM ICRRX MACUO IKHQU AJEGL OIJHH XPVZW JEWBA
FWAML ZZRXJ EKAHV FASMU LVVUT TGK";
# from Wikipedia
my $decode =-1;
my %EnglishLetterFreq = (
my $text=uc($ciphertext);
'E'=>12.70, 'L'=>4.03, 'Y'=>1.97, 'P'=>1.93, 'T'=>9.06, 'A'=>8.17, 'O'=>7.51, 'I'=>6.97, 'N'=>6.75,
$text=~s/[^A-Z]//g;
'S'=>6.33, 'H'=>6.09, 'R'=>5.99, 'D'=>4.25, 'C'=>2.78, 'U'=>2.76, 'M'=>2.41, 'W'=>2.36, 'F'=>2.23,
'G'=>2.02, 'B'=>1.29, 'V'=>0.98, 'K'=>0.77, 'J'=>0.15, 'X'=>0.15, 'Q'=>0.10, 'Z'=>0.07
);
# Kasiski examination
sub myguess{
$seqtext = $text;
#this is the hard part
while ($seqtext =~ /(...).*\1/) {
my %englishLetterFreq = (
$i = index($seqtext, $1);
#based on Wikipedia
$pos += $i++;
'E'=>12.70, 'L'=>4.03, 'Y'=>1.97, 'P'=>1.93, 'T'=>9.06, 'A'=>8.17, 'O'=>7.51, 'I'=>6.97, 'N'=>6.75, 'S'=>6.33, 'H'=>6.09, 'R'=>5.99, 'D'=>4.25, 'C'=>2.78, 'U'=>2.76, 'M'=>2.41, 'W'=>2.36, 'F'=>2.23, 'G'=>2.02, 'B'=>1.29, 'V'=>0.98, 'K'=>0.77, 'J'=>0.15, 'X'=>0.15, 'Q'=>0.10, 'Z'=>0.07);
$seqtext = substr($seqtext, $i);
$pos++;
$i = index($seqtext, $1);
push @spacing, $i+1;
}
for my ($text) =j (@_spacing); {
push @factors, grep { $j % $_ == 0 } 2..$j;
my ($seqtext,$pos,$i);
}
my @guesses;
$freq{$_}++ for @factors;
my @spacing;
@sortedfactors = grep { $_ >= 4 } sort { $freq{$b} <=> $freq{$a} } keys %freq; # discard very short keys
my @factors;
my @sortedfactors;
$seqtext=$text;
for my $keylen ( @sortedfactors[0..$max_key_lengths-1] ) {
$pos = 0;
my $keyguess = '';
while ($seqtext =~ /(...).*\1/) {
$i = index for ($seqtext,my $1); i = 0; $i < $keylen; $i++) {
$pos += $i; my($mykey, %chi_values, $bestguess);
$i++; for (my $j = 0; $j < length($text); $j += $keylen) {
$seqtextmykey .= substr($seqtexttext, ($j+$i); % length($text), 1);
$pos++; }
$i = index($seqtext, $1);
push @spacing, $i+1;
}
foreach my $j (@spacing) {
push @factors, (grep { $j % $_ == 0 }(2 .. $j));
}
my %freq;
$freq{$_}++ for @factors;
# score using chi-square values
foreach (sort { $freq{$b} <=> $freq{$a} } keys %freq) {
for my $subkey ('A'..'Z') {
push @sortedfactors, "$_";
my $decrypted = mycrypt($mykey, $subkey);
}
my $length = length($decrypted);
for my $char ('A'..'Z') {
splice @sortedfactors, $MAXKEYLENGTHS;
my $count = 0;
my $expected = $EnglishLetterFreq{$char} * $length / 100;
++$count while $decrypted =~ /$char/g;
$chi_values{$subkey} += ($count - $expected)**2 / $expected unless !$count;
}
}
$Keys{$keylen}{score} = $chi_values{'A'};
foreach my $keylen (@sortedfactors) {
for my $sk (sort keys %chi_values) {
my $keyguess;
for (my if ($ichi_values{$sk} <=0; $i<Keys{$keylen; $i++}{score}) {
$bestguess = $sk;
my $mykey;
$Keys{$keylen}{score} = $chi_values{$sk};
my %chivalues;
}
my $bestchi;
}
my $bestguess;
$keyguess .= $bestguess;
for (my $j=0; $j<length($text); $j+=$keylen) {
}
$mykey.=substr($text,($j+$i)%length($text),1);
$Keys{$keylen}{key} = $keyguess;
}
}
map { $Keys{$_}{key} } sort { $Keys{$a}{score} <=> $Keys{$b}{score}} keys %Keys;
foreach my $subkey ("A".."Z") {
my $chi=0;
my $decrypted=mycrypt($mykey,$subkey,$decode);
my $length = length($decrypted);
foreach my $char ("A".."Z") {
my $count=0;
my $expected = $length*$englishLetterFreq{$char}/100;
++$count while $decrypted =~ /\Q$char/g;
$chivalues{$subkey}+=($count - $expected)**2/$expected unless (!$count);
}
}
foreach my $sk (keys %chivalues) {
if (!$bestchi || $chivalues{$sk} < $bestchi) {
$bestchi = $chivalues{$sk};
$bestguess = $sk;
}
}
$keyguess.=$bestguess;
}
push @guesses, $keyguess;
}
return @guesses;
}
sub mycrypt {
my ($text, $key,$decode) = (@_);
my ($newtext, %values_numbers);
my $keylen=length($key);
my $newtext;
my %values_numbers;
@values_numbers {"A".."Z"} = (0..25);
my %values_letters = reverse %values_numbers;
for ( my $ikeylen =0; $i<length($textkey); $i++) {
@values_numbers{'A'..'Z'} = 0..25;
$newtext.=$values_letters{($values_numbers{substr($text,$i,1)}+$decode*$values_numbers{substr($key,($i%$keylen),1)})%26};
my %values_letters = reverse %values_numbers;
}
return $newtext;
for (my $i = 0; $i < length($text); $i++) {
my $val = -1 * $values_numbers{substr( $key, $i%$keylen, 1)} # negative shift for decode
+ $values_numbers{substr($text, $i, 1)};
$newtext .= $values_letters{ $val % 26 };
}
return $newtext;
}
my @guesses$ciphertext = myguess($text)<<~'EOD';
MOMUD EKAPV TQEFM OEVHP AJMII CDCTI FGYAG JSPXY ALUYM NSMYH
VUXJE LEPXJ FXGCM JHKDZ RYICU HYPUS PGIGM OIYHF WHTCQ KMLRD
ITLXZ LJFVQ GHOLW CUHLO MDSOE KTALU VYLNZ RFGBX PHVGA LWQIS
FGRPH JOOFW GUBYI LAPLA LCAFA AMKLG CETDW VOELJ IKGJB XPHVG
ALWQC SNWBU BYHCU HKOCE XJEYK BQKVY KIIEH GRLGH XEOLW AWFOJ
ILOVV RHPKD WIHKN ATUHN VRYAQ DIVHX FHRZV QWMWV LGSHN NLVZS
JLAKI FHXUF XJLXM TBLQV RXXHR FZXGV LRAJI EXPRV OSMNP KEPDT
LPRWM JAZPK LQUZA ALGZX GVLKL GJTUI ITDSU REZXJ ERXZS HMPST
MTEOE PAPJH SMFNB YVQUZ AALGA YDNMP AQOWT UHDBV TSMUE UIMVH
QGVRW AEFSP EMPVE PKXZY WLKJA GWALT VYYOB YIXOK IHPDS EVLEV
RVSGB JOGYW FHKBL GLXYA MVKIS KIEHY IMAPX UOISK PVAGN MZHPW
TTZPV XFCCD TUHJH WLAPF YULTB UXJLN SIJVV YOVDJ SOLXG TGRVO
SFRII CTMKO JFCQF KTINQ BWVHG TENLH HOGCS PSFPV GJOKM SIFPR
ZPAAS ATPTZ FTPPD PORRF TAXZP KALQA WMIUD BWNCT LEFKO ZQDLX
BUXJL ASIMR PNMBF ZCYLV WAPVF QRHZV ZGZEF KBYIO OFXYE VOWGB
BXVCB XBAWG LQKCM ICRRX MACUO IKHQU AJEGL OIJHH XPVZW JEWBA
FWAML ZZRXJ EKAHV FASMU LVVUT TGK
EOD
my $text = uc($ciphertext) =~ s/[^A-Z]//gr;
foreach my $f (@guesses) {
print "Key: $f\n";
for my $key ( myguess($text) ) {
print "Plaintext: ";
say "Key $key\n" .
print mycrypt ($text,$f,$decode);
"Key length " . length($key) . "\n" .
print "\n\n";
"Plaintext " . substr(mycrypt($text, $key), 0, 80) . "...\n";
}
}</lang>
print "\n";
exit;
</lang>
{{out}}
<pre>Key THECHESHIRECAT
<pre>
Key: EClength 14
Plaintext THISWASTHEPOEMTHATALICEREADJABBERWOCKYTWASBRILLIGANDTHESLITHYTOVESDIDGYREANDGIMB...
Plaintext: IMISZCGYLTPOADIMATDNWHIGEAZAPGBEUYCHONTWWJQWILOKUFRSTHAJANTHBVCAIHDIZXNWEAQFUNQQLEEEIMEWDDSFPAMIIJNBERHVVJFDROCFKJSAQFHMIBOMAIPYHSRWHLVPBEXVLFREWJSOEQBENNDHKMBUCSXWEJWNHYHAWDWYIIHEYCPBSTKCHHEICHXVLFREWJSOYQJUXSXWDAQFGMYCTHAWGZMIRWGGECDENJCFTCKJSYSDKHEJKTRPDNGBSGDIJYPSDLRPUYMBETDVBFNXROSKSTHEOFJLHTVQFJWIEDDVQDTHHVIRXJMTNVTFNDVVCTHPWHECTNNTKQILLIANZRHNNUIHWXLIHOQXWYHEVVCTHIHEFRQGERZQQPAXTHAPTXOFINORIRAMANWNFFOKBLXWROQXWYHEWWZLINWOKUPSDBXTPQISASEKRFMERPSYADONAKLTANGVVWSJGHWESYHRRWUMXWEVKIEFLBOCRJATNTOEXHKEUUBFGZHEHVUYITGGOIECDWEKWNTSKGOILTWEJKVFLUPRVNRVBAYBPSDHDUHYLDUSHRXSTHHLOGFTRWKTZHOMHVCRCPRMODNGEAPKGMFDYOBIPGJOXURFCRALHFDMCAONODLTCHKIIQEDLPVNWYOYPNPXBRLNZNKPNDPYTXLIWJMYSKESZZSLYRHCBIKXMBHVXSTHHYOGIPLLIZBXYWHTSYLTBONFVTVEVCBIXWEMKDTWATKUCZXVRAXVXYSEHOGAIGYPNVIYYSKGGFMSWHAEHMEHDFTNRXSHAUXYBUWKHXVPTHAIWFRDWQISHTRSPRCI
Key THECHESCIRECATTHECHESHIRECAT
Key: THECSAS
Key length 28
Plaintext: THISLESHIRRYENTHATPPIQFEGKDKABBEGAOQLLVGATBRILAMGOOQVRETLITHNXOJFFFSDHYREACHGWNONOIOTHEWPFEOMYOSMTYWERTXHSCBTYGPVESACHTVFZQWESATHSDYTUSNDOBFWAREILEXBODORXOCKMNWOBUUGTAXSTHAIFIHFGJOCMAWSTWETQBGERBFWAREILEXVOLEBCIRDACHSVVAVREGRUMIDYSPBAFORTNATCWLEHPBMRITVORPPPSKPEFSNIANDLDRGHJZGDHFMANXDQETPRJOSPUGHTHSRSTGGNHFBYTHTXUAUHODRFEANDHXOCENYRIMEINTWSUUIGCXDBSINUUJIGIGJYUHHTHEHXOCEGJOJBBBERLSCYXVVREZESOFUPAAFPCWEXHIFFAMNUUUTYUHHTHEIYLUFLYYOEANDBJVBZFQCCIUCAMEDREHXBQXEUWOANSXHFPHIRAODTHRDYGVUUGFOSPALBAEDSXRPDSOICKEGWNODXJOLFFTITSIARBAFGIUHITSWIARIRYONUGALUBTHWOTDKCLANDHPWTHIBWCLBINTHTNAPCRTGODKCOMTXOAZNTWSNYBEABMSVCBAYFSABJOJWDOZPCVLPOHCAAPAMIREROSTLEDXRHWTWQITXASBRXPLWHNPNTIESLIILYHPIGCDJDGYRTENRHVOLLFINTHTAAPFNNVMJMSYWTVEHIRDYRPGOVEHENRUUGWONERATWWOIUTTKBFITSETQSJFEAZRFTTYSWISOJQYREOSHEHPHFWOVUREEITBUIMTGSNVRESHARDISUBERTCTBND
Plaintext THISWASYHEPOEMTHATALICEREADJABBERWOHKYTWASBRILLIGANDTHESLITHYTOAESDIDGYREANDGIMB...
Key TJGGAHET
Key: THECHESHIRECAT
Key length 8
Plaintext: THISWASTHEPOEMTHATALICEREADJABBERWOCKYTWASBRILLIGANDTHESLITHYTOVESDIDGYREANDGIMBLEINTHEWABEALLMIMSYWERETHEBOROGOVESANDTHEMOMERATHSOUTGRABEBEWARETHEJABBERWOCKMYSONTHEJAWSTHATBITETHECLAWSTHATCATCHBEWARETHEJUBJUBBIRDANDSHUNTHEFRUMIOUSBANDERSNATCHHETOOKHISVORPALSWORDINHANDLONGTIMETHEMANXOMEFOEHESOUGHTSORESTEDHEBYTHETUMTUMTREEANDSTOODAWHILEINTHOUGHTANDASINUFFISHTHOUGHTHESTOODTHEJABBERWOCKWITHEYESOFFLAMECAMEWHIFFLINGTHROUGHTHETULGEYWOODANDBURBLEDASITCAMEONETWOONETWOANDTHROUGHANDTHROUGHTHEVORPALBLADEWENTSNICKERSNACKHELEFTITDEADANDWITHITSHEADHEWENTGALUMPHINGBACKANDHASTTHOUSLAINTHEJABBERWOCKCOMETOMYARMSMYBEAMISHBOYOFRABJOUSDAYCALLOOHCALLAYHECHORTLEDINHISJOYTWASBRILLIGANDTHESLITHYTOVESDIDGYREANDGIMBLEINTHEWABEALLMIMSYWERETHEBOROGOVESANDTHEMOMERATHSOUTGRABEITSEEMSVERYPRETTYSHESAIDWHENSHEHADFINISHEDITBUTITSRATHERHARDTOUNDERSTAND
Plaintext TFGODXGHWMNKEYIVLMBJACIPPTXWTBBNFRADSITFHCOSMGOTFYPOXCASLGRDFQCJTABEDSNFPTOBYIQZ...
Key: THEC THECSAS
Key length 7
Plaintext: THISKXGYWOPOLYIMLODNHCIGPVZAABBEFTCHZITWHEQWTGOKFARSECAJLITHMQCATCDIKSNWPVQFFIQQWZEETHEWOYSFAVMITENBPMHVGEFDCJCFVESABAHMTWOMLDPYSNRWSGVPMZXVWAREHESOPLBEYIDHVHBUNNXWPEWNSTHAHYWYTDHEJXPBDOKCSCEINCXVWAREHESOJLJUINXWOVQFRHYCECAWRUMICRGGPXDEYECFEXKJDTSDVCEJVORPOIGBDBDIUTPSOGRPFTMBPODVMANXCJSKDOHEZAJLSOVQQEWIPYDVBYTHSQIRIEMTYQTFYYVVNOHPHCECEINTVLILWDANKMHNYPIHHSLISJQXHTHEGQCTSDHEQMQGPMZQBKAXECAPESOFTIORTMAMLIWNQAOKMGXWCJQXHTHEHRZLTIWOVPPSOWXTALISLNEKCAMECKSYLYONLFLTLIGVGRSJRCWEDTHRCRUMIREVVDEFWWOCCEATYOOEICKEFPBFRUHESQUYTOGGZDECOREKHITSVBOIWOWEUFVFWPPRGIRVMVYBANDHOPHYWYUSSMXSECHLZBFTCRKTKCOMSQCRNKRMZYNGPVPKRHFDJJBIABJOIPRFNMALSADMNVONZYLTNCKITLEDWKVNHTOYAIPXMMLNKIKPYYPYESLIHEMYDFESKUSLJMHCMDKXXWHVINTHSTOGTKLLTUBXJRHTDTLTMJNFGOVEGXBIIREMVYTWLOKUNUXVCVXVITSESJGATBYPYQIYJNKGRAMSHCAESHEHOATNCSSHLPXYMPWKSSVPECAIHARDHLISSORSAMCI
Plaintext THISLESHIRRYENTHATPPIQFEGKDKABBEGAOQLLVGATBRILAMGOOQVRETLITHNXOJFFFSDHYREACHGWNO...
Key THEC
Key: THECHESCIRECATTHECHESHIRECAT
Key length 4
Plaintext: THISWASYHEPOEMTHATALICEREADJABBERWOHKYTWASBRILLIGANDTHESLITHYTOAESDIDGYREANDGIMBLEINTHEWABEFLLMIMSYWERETHEBOROGOVESANDTMEMOMERATHSOUTGRABEBEWARETHEOABBERWOCKMYSONTHEJAWSTHATBIYETHECLAWSTHATCATCHBEWARETHEOUBJUBBIRDANDSHUNTHEFRUMIOUSGANDERSNATCHHETOOKHISVORPALSBORDINHANDLONGTIMETHEMANXOMEKOEHESOUGHTSORESTEDHEBYTHETURTUMTREEANDSTOODAWHILEINTHOULHTANDASINUFFISHTHOUGHTHESTOTDTHEJABBERWOCKWITHEYESOFFLARECAMEWHIFFLINGTHROUGHTHETULLEYWOODANDBURBLEDASITCAMEONEYWOONETWOANDTHROUGHANDTHROUGMTHEVORPALBLADEWENTSNICKERSNFCKHELEFTITDEADANDWITHITSHEAIHEWENTGALUMPHINGBACKANDHASTYHOUSLAINTHEJABBERWOCKCOMETORYARMSMYBEAMISHBOYOFRABJOUSDFYCALLOOHCALLAYHECHORTLEDINHNSJOYTWASBRILLIGANDTHESLITHYYOVESDIDGYREANDGIMBLEINTHEWAGEALLMIMSYWERETHEBOROGOVESANITHEMOMERATHSOUTGRABEITSEEMSAERYPRETTYSHESAIDWHENSHEHADFNNISHEDITBUTITSRATHERHARDTOUSDERSTAND
Plaintext THISKXGYWOPOLYIMLODNHCIGPVZAABBEFTCHZITWHEQWTGOKFARSECAJLITHMQCATCDIKSNWPVQFFIQQ...</pre>
</pre>
=={{header|Phix}}==
|