Data commit

Task/Substitution-cipher/Perl/substitution-cipher.pl

@@ -0,0 +1,43 @@
+sub encode {
+    my $source = shift;
+    my $key = shift;
+    my $out = q();
+
+    @ka = split //, $key;
+    foreach $ch (split //, $source) {
+        $idx = ord($ch) - 32;
+        $out .= $ka[$idx];
+    }
+
+    return $out;
+}
+
+sub decode {
+    my $source = shift;
+    my $key = shift;
+    my $out = q();
+
+    foreach $ch (split //, $source) {
+        $idx = index $key, $ch;
+        $val = chr($idx + 32);
+        $out .= $val;
+    }
+
+    return $out;
+}
+
+my $key = q(]kYV}(!7P$n5_0i R:?jOWtF/=-pe'AD&@r6%ZXs"v*N[#wSl9zq2^+g;LoB`aGh{3.HIu4fbK)mU8|dMET><,Qc\C1yxJ);
+my $text = "Here we have to do is there will be a input/source "
+         . "file in which we are going to Encrypt the file by replacing every "
+         . "upper/lower case alphabets of the source file with another "
+         . "predetermined upper/lower case alphabets or symbols and save "
+         . "it into another output/encrypted file and then again convert "
+         . "that output/encrypted file into original/decrypted file. This "
+         . "type of Encryption/Decryption scheme is often called a "
+         . "Substitution Cipher.";
+
+my $ct = encode($text, $key);
+print "Encoded: $ct\n";
+
+my $pt = decode($ct, $key);
+print "Decoded: $pt\n";