[SOLVED] FFFD ascii character

[5kyy8lu3]

Hi.  I wrote a simple encryption script, for fun, and I can't get it to work.  I make an array with 1-255, then shuffle it with shuffle() then make a new array with keys 1 through 255 and give the values of the shuffled array to the new one, so each ascii code has a new code it "converts" to, so it's a pseudo "encryption table" kinda deal.  I then go one character at a time with substr and convert each character using that array.

 

When I decrypt it, I get this weird square FFFD character that's randomly taking the place of some character.  Since the encryption is random, each time i refresh the page it outputs FFFD character in place of a different string.

 

So my question is, is this causes by a string that isn't "compatible" with being converted to something and then back?  I could skip "bad" characters but I don't even know what's causing this so it's hard to find a solution.

 

Here's what I get as a result when I encrypt, then decrypt "What is g�oing� on with this script???"

 

What is �oin� on with this script???

What �s g��ng �n w�th th�s scr��t???

Wh�� is �oin� on wi�h �his s��ip�???

What�i��going�on�with�thi���cript���

What �s �o�n� on w�th th�s scr�pt???

W�at i� going on �it� t�i� �cri�t���

 

The missing characters are those FFFD characters but they don't seem to copy/paste.  Any ideas?

 

Here's the code:

 

<?php
echo '<pre>';
function encrypt($Incoming)
{
	$Codes = array("32", "33", "34", "35", "36", "37", "38", "39", "40", 
				"41", "42", "43", "44", "45", "46", "47", "48", "49", 
				"50", "51", "52", "53", "54", "55", "56", "57", "58", 
				"59", "60", "61", "62", "63", "64", "65", "66", "67", 
				"68", "69", "70", "71", "72", "73", "74", "75", "76", 
				"77", "78", "79", "80", "81", "82", "83", "84", "85", 
				"86", "87", "88", "89", "90", "91", "92", "93", "94", 
				"95", "96", "97", "98", "99", "100", "101", "102", "103", 
				"104", "105", "106", "107", "108", "109", "110", "111", 
				"112", "113", "114", "115", "116", "117", "118", "119", 
				"120", "121", "122", "123", "124", "125", "126");
	shuffle($Codes);
	$count = 0;
	for ( $i = 32; $i < 127; $i++ )
		{
			$CryptTable[$i] = $Codes[$count];
			$count++;
		}
	for ( $i = 0; $i < strlen($Incoming); $i++)
		{
			$NewString = $NewString . chr($CryptTable[ord(substr($Incoming, $i, 1))]);
		}
	for ( $i = 32; $i < 127; $i++ )
		{
			if ( $CryptTable[$i] < 100 )
				{
					$CryptTable[$i] = 'x' . $CryptTable[$i];
				}
			$Key = $Key . str_replace('0', 'x', $CryptTable[$i]);
		}
	$Keyed = substr($Key, 0, 144) . $NewString . substr($Key, -141);
	return($Keyed);
}
function decrypt($Incoming)
{
	$Key = substr($Incoming, 0, 144) . substr($Incoming, -141);
	$string = substr($Incoming, 144, ( strlen($Incoming) - 285 ));
	$count = 0;
	for ( $i = 32; $i < 127; $i++ )
		{
			$DeCryptTable[str_replace('x', '', substr($Key, $count, 3))] = $i;
			$count = $count + 3;
		}
	for ( $i = 0; $i < strlen($string); $i++ )
		{
			$NewString = $NewString . chr($DeCryptTable[ord(substr($string, $i, 1))]);
		}
	return($NewString);
}
echo decrypt(encrypt("What is going on with this script???"));
?>

 

Thanks =)

 

 

[5kyy8lu3]

So, I limited the range of characters I convert from chr(33) to chr(126) to make sure I don't have any special characters screwing this up.  It still does the same thing.

 

I tried a for loop echo'ing chr(32) through chr(126) and I don't see that FFFD character anywhere, so in theory it shouldn't in my decryption output either but it still does =/

 

any ideas?

[Zane]

I'm sorry but you're gonna have to elaborate a little more on this FFFD character.  I'm sure I already know which one it is ... it's probably on the tip of my tongue..or I've forgotten or something..can you please tell us what this character is exactly...just for clarification if anything else.

[5kyy8lu3]

I'm sorry but you're gonna have to elaborate a little more on this FFFD character.  I'm sure I already know which one it is ... it's probably on the tip of my tongue..or I've forgotten or something..can you please tell us what this character is exactly...just for clarification if anything else.

 

this:

[Zane]

so it's showing all 65,025 of them except that one?  65,024 ascii characters

 

In other news...this is useful ..perhaps

http://forums.whirlpool.net.au/forum-replies-archive.cfm/1178058.html

[5kyy8lu3]

so it's showing all 65,025 of them except that one?  65,024 ascii characters

i'm only playing with 32 through 126.

 

example:

<?php
echo '<pre>';
for ( $i = 33; $i < 127; $i++ )
{
	echo $i . ' ' . chr($i) . '<br>';
}
?>

 

which works fine.  but when I decrypt my encrypted text, some characters show up as that "fffd" character, which google searching tells me means it's trying to display an invalid character, which is B.S. because I did a print_r() on my decryption table and all the ascii codes are within the 33-126, which ALL work fine using that above script.

 

i'm stumped =*(

[5kyy8lu3]

Ok I think I figured it out.

 

Not sure what I did exactly but I made things more "definite" and it works this time around.

 

here's the code incase anyone is curious of how my super primitive encryption works lol:

 

<?php
echo '<pre>';
function encrypt($Incoming)
{
	for ( $i = 33; $i < 255; $i++ )
		{
			$Codes[] = $i;
		}
	shuffle($Codes);
	$count = 0;
	for ( $i = 33; $i < 255; $i++ )
		{
			$CryptTable[$i] = $Codes[$count];
			$count++;
		}
	for ( $i = 0; $i < strlen($Incoming); $i++)
		{
			$Byte = substr($Incoming, $i, 1);
			$AsciiCode = ord($Byte);
			if ( ( $AsciiCode > 32 ) && ( $AsciiCode < 255 ) )
				{
					$NewCode = $CryptTable[$AsciiCode];
					$NewString = $NewString . chr($NewCode);
				}
			else
				{
					$NewString = $NewString . $Byte;
				}
		}
	for ( $i = 33; $i < 255; $i++ )
		{
			if ( $CryptTable[$i] < 100 )
				{
					$CryptTable[$i] = 'x' . $CryptTable[$i];
				}
			$Key = $Key . $CryptTable[$i];
		}
	$Keyed = substr($Key, 0, 333) . $NewString . substr($Key, 333);
	return($Keyed);
}
function decrypt($Incoming)
{
	$Key = substr($Incoming, 0, 333) . substr($Incoming, -333);
	$string = substr($Incoming, 333, ( strlen($Incoming) - 666 ));
	$count = 0;
	for ( $i = 33; $i < 255; $i++ )
		{
			$DeCryptTable[str_replace('x', '', substr($Key, $count, 3))] = $i;
			$count = $count + 3;
		}
	for ( $i = 0; $i < strlen($string); $i++ )
		{
			$Byte = substr($string, $i, 1);
			$AsciiCode = ord($Byte);
			if ( ( $AsciiCode > 32 ) && ( $AsciiCode < 255 ) )
				{
					$NewCode = $DeCryptTable[$AsciiCode];
					$NewString = $NewString . chr($NewCode);
				}
			else
				{
					$NewString = $NewString . $Byte;
				}
		}
	return($NewString);
}
$a = encrypt("What is going on with this script???");
echo 'Encrypted: ' . $a . '<br><br>';
echo 'Decrypted: ' . decrypt($a);
?>