#!/usr/bin/perl #--------------------------------------------------------------------- +------------------------ # @Script CLI args@ # 1) action: "e" or "d", as one char string # 2) password: "myDesPass", as a string # 3) input file: "filePath1", as a string, should contain the message + to encrypt # 4) output file: "filePath2", as a string, where the encrypted messag +e will be saved #--------------------------------------------------------------------- +------------------------ #--------------------------------------------------------------------- +------------------------ # Ctyptography and Network Security 4th edition by Willian Stallings # # DES online calculator: # https://www.emvlab.org/descalc # # Perl tutorial: # https://www.tutorialspoint.com/perl/ # http://www.perlmonks.org/ # # unpack/pack: # https://www.tutorialspoint.com/perl/perl_unpack.htm # # perl references: # https://perlmaven.com/array-references-in-perl # # Programmatic Conversions: # http://perltips.wikidot.com/convert-hex-dec-oct-bin # https://stackoverflow.com/questions/288900/how-can-i-convert-a-strin +g-to-a-number-in-perl # # Online Conversions: # http://www.rapidtables.com/convert/number/hex-to-ascii.htm # http://www.asciitohex.com/ # #--------------------------------------------------------------------- +------------------------ #--------------------------------------------------------------------- +------------------------ # DES Internal Conversion Tables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my @IP = ( 58,50,42,34,26,18,10,2, 60,52,44,36,28,20,12,4, 62,54,46,38,30,22,14,6, 64,56,48,40,32,24,16,8, 57,49,41,33,25,17, 9,1, 59,51,43,35,27,19,11,3, 61,53,45,37,29,21,13,5, 63,55,47,39,31,23,15,7 ); my @IP_INVERSE = ( 40,8,48,16,56,24,64,32, 39,7,47,15,55,23,63,31, 38,6,46,14,54,22,62,30, 37,5,45,13,53,21,61,29, 36,,4,44,12,52,20,60,28, 35,3,43,11,51,19,59,27, 34,2,42,10,50,18,58,26, 33,1,41,9,49,17,57,25 ); my @E = ( 32,1,2,3,4,5, 4,5,6,7,8,9, 8,9,10,11,12,13, 12,13,14,15,16,17, 16,17,18,19,20,21, 20,21,22,23,24,25, 24,25,26,27,28,29, 28,29,30,31,32,1 ); my @P = ( 16,7,20,21,29,12,28,17, 1,15,23,26,5,18,31,10, 2,8,24,14,32,27,3,9, 19,13,30,6,22,11,4,25 ); my @PC_1 = ( 57,49,41,33,25,17,9, ,1,58,50,42,34,26,18, 10,2,59,51,43,35,27, 19,11,3,60,52,44,36, 63,55,47,39,31,23,15, 7,62,54,46,38,30,22, 14,6,61,53,45,37,29, 21,13,5,28,20,12,4 ); my @PC_2 = ( 14,17,11,24,1,5,3,28, 15,6,21,10,23,19,12,4, 26,8,16,7,27,20,13,2, 41,52,31,37,47,55,30,40, 51,45,33,48,44,49,39,56, 34,53,46,42,50,36,29,32 ); my @ScheduleOfLeftShifts = (1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, +2, 1); #--------------------------------------------------------------------- +------------------------ #--------------------------------------------------------------------- +------------------------ # Globals and CLI args #--------------------------------------------------------------------- +------------------------ my $action = checkAction($ARGV[0]); my $subKeysRef = createRoundKeys($ARGV[1]); my $InputFileName = $ARGV[2]; my $OutputFileName = $ARGV[3]; # this is an array where each element is a ref to a bits-array of the +index/round sub-key # @$: dereference a refrence to an array my @SubKeys = @$subKeysRef; # holds data to read/write from/to file my @FileArray = (); #--------------------------------------------------------------------- +------------------------ #--------------------------------------------------------------------- +------------------------ # #--------------------------------------------------------------------- +------------------------ sub checkAction { my $action = $_[0]; if( ($action eq "e") or ($action eq "d") ) { return $action; } else { die "#ERROR: action parameter is wrong (\"e\"=encryption, \"d\ +"=decryption)#\n"; } } #--------------------------------------------------------------------- +------------------------ #--------------------------------------------------------------------- +------------------------ # #--------------------------------------------------------------------- +------------------------ sub createRoundKeys { my $key = $_[0]; if(length $key != 8) { die "#ERROR: DES key is not 64 bit#\n";} my $i, $j; # to hold references to sub-keys for each round according to array + index. # the function returns a reference of this array to be farther use +d. my @subKeys = (); # unpack returns the key string as a corresponding bit string # 64 bit where B indicates highest first my @tempArr = unpack("B64", $key); # split bit string to corresponding bits array my @keyBitsArr = split("", $tempArr[0]); #convert to numeric bits for ($j=0; $j<=$#keyBitsArr; $j++) { $keyBitsArr[$j]+=0; } #------------------------------------------------------------ # permuted choice one(@PC_1) # each index in the keyBitsArr56_PC1 gets some bit from the 64-bit + original key according to some mapping, PC-1 my @keyBitsArr56_PC1 = (); for ($i=0; $i<=$#PC_1; $i++) { $keyBitsArr56_PC1[$i] = $keyBitsArr[$PC_1[$i]-1]; } # split permuted choice 1 outcome @keyBitsArr56_PC1 to two 28 bit +arrays, left and right my @leftBitsArr = (); my @rightBitsArr = (); for($i=0; $i<28; $i++) { $leftBitsArr[$i] = $keyBitsArr56_PC1[$i]; } for(; $i<56; $i++) { $rightBitsArr[$i-28] = $keyBitsArr56_PC1[$i]; } #------------------------------------------------------------ #------------------------------------------------------------ # create sub-keys for each round @tempArr = (); for($i=0; $i<16; $i++) { # shift each part individually for($j=0; $j<$ScheduleOfLeftShifts[$i]; $j++) { # shift left part according to round push(@leftBitsArr, shift(@leftBitsArr)); # shift right part according to round push(@rightBitsArr, shift(@rightBitsArr)); } # PC_2, get 48 bit round sub key # unite to one 56 bits arr for($j=0; $j<28; $j++) { $tempArr[$j] = $leftBitsArr[$j]; $tempArr[$j+28] = $rightBitsArr[$j]; } # permuted choice two for ($j=0; $j<=$#PC_2; $j++) { # save round key ${$subKeys[$i]}[$j] = $tempArr[$PC_2[$j]-1]; } } #------------------------------------------------------------ return \@subKeys; } #--------------------------------------------------------------------- +------------------------ #--------------------------------------------------------------------- +------------------------ # #--------------------------------------------------------------------- +------------------------ sub des { my $i, $j, $k, $tempVar, @tempArr; # iterate over input file in chunks of 64 bit, DES ECB-mode of ope +ration for($i=0; $i<=$#FileArray; $i++) { # convert block read from file to its binary rep $tempVar = unpack("B64", $FileArray[$i]); #---------------------------------------- # DEBUG/PoC print("$FileArray[$i]\n"); $hex = sprintf('%X', oct("0b$tempVar")); print("$hex\n"); #---------------------------------------- # an array of bits as numeric values, the block rep as numeric + binary numbers my @bitsArray = split("", $tempVar); #convert to numeric bits for ($j=0; $j<=$#bitsArray; $j++) { $bitsArray[$j]+=0; } # initial permutation (IP) for each block/64 bit chunk before +the 16 rounds my @bitsArray_ip = (); for ($j=0; $j<=$#IP; $j++) { $bitsArray_ip[$j] = $bitsArray[$IP[$j]-1]; } # split to: left and right my @leftBitsArr = (); my @rightBitsArr = (); for ($j=0; $j<32; $j++) { $leftBitsArr[$j] = $bitsArray_ip[$j]; $rightBitsArr[$j] = $bitsArray_ip[$j+32]; } # 16 DES rounds per 64 bit chunk treated as two 32 bit chunks for($j=0; $j<16; $j++) { my @nextLeftBitsArr = @rightBitsArr; # curr right bits chunk expansion/permutation (E) my @bitsArray_E = (); for($k=0; $k<=$#E; $k++) { $bitsArray_E[$k] = $rightBitsArr[$E[$k]-1]; } @rightBitsArr = @bitsArray_E;# copy back # XOR with round sub-key: check function bool param for en +cryption/decryption action my $ref; if($action eq "e") { $ref = $SubKeys[$j];# j - index of curr round } elsif($action eq "d") { $ref = $SubKeys[15-$j];# j - index of curr round reve +rsed } my @roundSubKey = @$ref;# de-ref to bits-array for($k=0; $k<48; $k++) { $rightBitsArr[$k]^=$roundSubKey[$k]; } # S-box my $sBoxResStr = ""; for($k=0; $k<8; $k++) { @tempArr = unpack("N", pack("B32", ("0"x30).join("",($ +rightBitsArr[$k*6], $rightBitsArr[$k*6+5])))); my $sBoxRow = $tempArr[0]; @tempArr = unpack("N", pack("B32", ("0"x28).join("",($ +rightBitsArr[$k*6+1], $rightBitsArr[$k*6+2], $rightBitsArr[$k*6+3], $ +rightBitsArr[$k*6+4])))); my $sBoxCol = $tempArr[0]; my $sBoxOutput = $SBOXES[$k][$sBoxRow][$sBoxCol]; @tempArr = unpack("B32", pack("N", $sBoxOutput)); $sBoxResStr.=substr($tempArr[0], -4); } @rightBitsArr = split("", $sBoxResStr);# now 32 bits, $sBo +xResStr was loop concat. #convert to numeric bits for ($k=0; $k<=$#rightBitsArr; $k++) { $rightBitsArr[$k]+=0; } # permutation(P) my @bitsArray_p = (); for ($k=0; $k<=$#P; $k++) { $bitsArray_p[$k] = $rightBitsArr[$P[$k]-1]; } @rightBitsArr = @bitsArray_p;# now 32 bits # XOR result on curr right bits chunk with curr left bits +chunk, put res to next right chunk for($k=0; $k<32; $k++) { $rightBitsArr[$k] ^= $leftBitsArr[$k]; } # assign next values @leftBitsArr = @nextLeftBitsArr; } # swap two sides @temp = @leftBitsArr; @leftBitsArr = @rightBitsArr; @rightBitsArr = @temp; # merge and inverse initial permutation --> output 64 bit chun +k cipher-text for($k=0; $k<32; $k++) { $bitsArray[$k] = $leftBitsArr[$k]; $bitsArray[$k+32] = $rightBitsArr[$k]; } my @bitsArray_ip_inverse = (); for ($k=0; $k<=$#IP_INVERSE; $k++) { $bitsArray_ip_inverse[$k] = $bitsArray[$IP_INVERSE[$k]-1]; } #save manipulated chunk to same index in @FileArray $tempVar = join("", @bitsArray_ip_inverse); $FileArray[$i] = pack("B64", $tempVar); } } #--------------------------------------------------------------------- +------------------------ #--------------------------------------------------------------------- +------------------------ # I/O functions #--------------------------------------------------------------------- +------------------------ sub readInputToArray { open(FILEHANDLER, "<".$InputFileName) or die "#ERROR: can't open i +nput file#\n"; my $i = 0; while(1) { # read a block of data, block size is 8 bytes/64 bits $bytes = read (FILEHANDLER, $chunk, 8); if($bytes == 0) { last; } else { $FileArray[$i] = $chunk; $i++; } } close(FILEHANDLER) or die "#ERROR: couldn't close input file prope +rly#\n"; if($action eq "e"){ # padding at the end to fit 8 byte/64 bit chunks for DES block +s my $lastBlockSize = length $FileArray[$#FileArray]; my $diff = 0; if( $lastBlockSize < 8) { $diff = 8 - $lastBlockSize; # create the padding string my $padding = "0" x $diff; # concat last block to pedding string $FileArray[$#FileArray].=$padding; } open(FILEHANDLER, ">.DES_PROPERTIES.txt") or die "#ERROR: can' +t open .DES_PROPERTIES.txt file#\n"; print FILEHANDLER "des_padding_diff\n$diff\n"; close(FILEHANDLER) or die "#ERROR: couldn't close .DES_PROPERT +IES.txt file properly#\n"; } } sub writeOutputToFile { if($action eq "d"){ open(FILEHANDLER, "<.DES_PROPERTIES.txt") or die "#ERROR: can' +t open DES_PROPERTIES.txt file#\n"; @lines = <FILEHANDLER>; $diff = $lines[1]; close(FILEHANDLER) or die "#ERROR: couldn't close DES_PROPERTI +ES.txt file properly#\n"; } open(FILEHANDLER, ">".$OutputFileName) or die "#ERROR: can't open +output file#\n"; for(my $i=0; $i<=$#FileArray; $i++) { if($i == $#FileArray) { $FileArray[$i] = substr($FileArray[$i], 0, length($FileArr +ay[$i])-$diff); } print FILEHANDLER $FileArray[$i]; } close(FILEHANDLER) or die "#ERROR: couldn't close output file prop +erly#\n"; } #--------------------------------------------------------------------- +----------- #--------------------------------------------------------------------- +----------- # Execute #--------------------------------------------------------------------- +----------- readInputToArray(); des(); writeOutputToFile(); #--------------------------------------------------------------------- +-----------
In reply to DES in Perl by TomY
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