##Authored by Troy Osborne (Pseudomander) 4:45am 25/02/2012 AEST +10 ##

##Free to redistribute, use, copy, upload & adapt this work, all I ask is if it in anyway represents the original version please give credit where due##



use warnings;



$key="";

$offsetpattern="";

$offsetpattern2="";

while (length($key) < 4)

{

	print "Please Enter Your Desired Key (5 or more characters) \n --> :";

	chomp($key=<>);

}

@karray= split(//,$key);

for ($i=0;$i<length($key);$i++)

{

	$temp =0;

	for ($i2=0;$i2<length($key);$i2++) 

		{	

			$temp += (ord($karray[$i])+ord($karray[$i2]));

			$offsetpattern .= chr((ord($karray[$i])+ord($karray[$i2]))%256);

		}

	$offsetpattern2.=chr(int($temp /length($key))%256);

}

@offset = split(//,$offsetpattern);

@offset2 = split(//,$offsetpattern2);





print "Encrypt or Decrypt (E/D)\n --> :";

$inp=<>;

if (($inp=~/E/) or ($inp=~/e/))

#Encryption

{

	print "Enter Plaintext\n --> :";

	chomp($plaintext = <>); 

	$len = length($plaintext)-1;

	@array = split(//, $plaintext);

	for ($i=0;$i<$len;$i++)

	{

		$char = chr((ord($array[$i]) - ord($offset[$i % length($key)*length($key)])+ ord($offset2[$i % length($key)]))%256);

		print chr(ord($char)-($i%6));

	}

}

elsif (($inp=~/D/) or ($inp=~/d/))

#Decryption

{

	print "Enter Cyphertext\n --> :";

	chomp($cyphertext = <>);

	$len = length($cyphertext)-1;

	@array = split(//, $cyphertext);

	for ($i=0;$i<$len;$i++)

	{

		$char = chr((ord($array[$i]) + ord($offset[$i % length($key)*length($key)]) - ord($offset2[$i % length($key)]))%256);

		print chr(ord($char)+($i%6));

	}

}

<>;