Hi everyone

Sorry for posting all my code but I wanted you to be able to load it up fairly quickly and see what's happening.

Is is a very basic "roll your own basic encryption by s/// chars". I created a hash with my randomoness. When you load the application it asks you to encrypt or decrypt, if you encrypt and encrypt a file you actually have it'll perform an encryption. That part works.

However, when you then go back and choose to decrypt the file you just created it doesn't decrypt. It creates a new file and the only ouput I'm getting is a "^" for every character in the file. No other letters, numbers or characters. The output is just carrets.

What am I doing wrong? I assumed I could just reverse my map with s/$map{$key}/$key)/ but that doesn't seem to be the case.

Can someone see what I'm doing wrong? This is for a class and I know there are better ways to do it but this is what they're looking for.

#!/usr/bin/perl

use warnings;
use strict;

#map contains our character mapping to expedite character replacement/
+encryption
my %map = (
"a" => "i",
"A" => "j",
"b" => "s",
"B" => "4",
"c" => "S",
"C" => 'Y',
"d" => "u",
"D" => "t",
"e" => "a",
"E" => "O",
"f" => "&",
"F" => " ",
"g" => "A",
"G" => "v",
"h" => "g",
"H" => "J",
"i" => "%",
"I" => "B",
"j" => "\$",
"J" => "T",
"k" => "K",
"K" => "k",
"l" => "@",
"L" => "#",
"m" => "!",
"M" => "b",
"n" => "0",
"N" => "M",
"o" => "q",
"O" => "l",
"p" => "r",
"P" => "R",
"q" => "U",
"Q" => "Q",
"r" => "n",
"R" => "C",
"s" => "9",
"S" => "G",
"t" => "8",
"T" => "L",
"u" => "i",
"U" => "7",
"v" => "h",
"V" => ",",
"w" => "H",
"W" => "P",
"x" => "6",
"X" => "m",
"y" => "c",
"Y" => "x",
"z" => "5",
"Z" => "w",
"1" => "F",
"2" => "y",
"3" => "z",
"4" => "Z",
"5" => "p",
"6" => "f",
"7" => "W",
"8" => "v",
"9" => "3",
"0" => "E",
"!" => "d",
"@" => "2",
"#" => "1",
"\$" => "e",
"%" => "D",
"^" => ".",
"&" => "n",
"," => "x",
"," => "o",
" " => "~"
);

print "\n\nWould you like to Encrypt or Decrypt a file [e/d]? ";
my $action = <STDIN>;
chomp($action);

# If action matches the letter e, perform an encryption
if ($action =~ m/e/i)
{
   print "\n";
   print "Enter input file name: ";
   my $infile = <STDIN>;
   chomp($infile);


   print "Enter output file name: ";
   my $outfile = <STDIN>;
   chomp($outfile);

   # open source file for reading and store it locally (and check for 
+errors)
   open(INFILE, $infile) or die "Error opening input file $infile: $!"
+;
   my @source = <INFILE>;
   close(INFILE) or die "Error closing input file $infile: $!";


   # since we stored the data from the source file as an array (like w
+e had to)
   #  we need to now join everything together as a large scalar to per
+form s///
   my $source = join("", @source);

   foreach my $key (keys %map)
   {  
       $source =~ s/$key/$map{$key}/g;
   } 

   open(OUTFILE, ">$outfile") or die "Error creating new file $outfile
+: $!";
   print OUTFILE $source;
   close(OUTFILE) or die "Error closing new file $outfile: $!";

   sleep(5); # for added affect!
   print "\n\nEncryption completed.\n\n";
   exit;
}
elsif($action =~ m/d/i)
{
   print "Enter file name to decrypt: ";
   my $infile = <STDIN>;
   chomp($infile);

   print "Enter output file name: ";
   my $outfile = <STDIN>;
   chomp($outfile);

   open(INFILE, $infile) or die "Error opening input file $infile: $!"
+;
   my @source = <INFILE>;
   close(INFILE) or die "Error closing input file $infile: $!";

   # since we stored the data from the source file as an array (like w
+e had to)
   #  we need to now join everything together as a large scalar to per
+form s///
   my $source = join("", @source);

   foreach my $key (keys %map)
   {  
       $source =~ s/$map{$key}/$key/g;
   } 

   open(OUTFILE, ">$outfile") or die "Error creating new file $outfile
+: $!";
   print OUTFILE $source;
   close(OUTFILE) or die "Error closing new file $outfile: $!";

   print "Decryption completed.";
   exit;

}
else
{
   print "Sorry, I did not understand your command.";
   print "\nPlease run this program again, and";
   print "\nType in \"e\" to encrypt a file or \"d\" to decrypt a file
+\n\n";
}

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In reply to Using a hash to globally s/// a string by Anonymous Monk

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