explain xor to me please

[Anon]

Can somebody explain the 'xor' logic to me please ?

[funch27]

$a xor $b Result is True if either $a or $b is True, but not both.

$a = 1;
$b = 0;

$a xor $b ---> returns true;

$a = 0;
$b = 1;

$a xor $b ----> returns true;

$a = 1;
$b = 1;

$a xor $b ----> returns false;

$a = 0;
$b= 0;

$a xor $b ----> returns false;

[neuromancer]

If you have two numbers as follows XOR will take what is true in the first or second but not both resulting in the third number

110101010101011101

001011010100110101

111110000001101000

[Anon]

Here are a few little functions to encrypt/decrypt a string with a key.

$input is the string to encrypt/decrypt and key is just a sting to use as a key, any ol string will do.

function encrypt_xor($input,$key){
$key_len = strlen($key) - 1;
$input_len = strlen($input) - 1;

while($input_cnt <= $input_len){
if($key_cnt >= $key_len){
$cur_key = $key[$key_cnt];
$key_cnt = 0;
}
else{
$cur_key = $key[$key_cnt];
$key_cnt++;
}

$output .= chr(ord($input[$input_cnt])^{ord($cur_key));}
$input_cnt++;
}
return $output;
}

function decrypt_xor($input,$key){
$key_len = strlen($key) - 1;
$input_len = strlen($input) - 1;

while($input_cnt <= $input_len){
if($key_cnt >= $key_len){
$cur_key = $key[$key_cnt];
$key_cnt = 0;
}
else{
$cur_key = $key[$key_cnt];
$key_cnt++;
}

$output .= chr(ord($input[$input_cnt])^{ord($cur_key));}
$input_cnt++;
}
return $output;
}