PHP XOR strings

Question

I saw this code from an answer on PPCG:

echo BeeABBeeoBodBaBdOdPQBBgDQgDdp^"\n\n\t8b\n\n\t\nb&\nb b  \n%%nb%%%\n%\nQ";

I know PHP casts undefined constants into strings, so the equivalent code is:

echo 'BeeABBeeoBodBaBdOdPQBBgDQgDdp' ^ "\n\n\t8b\n\n\t\nb&\nb b  \n%%nb%%%\n%\nQ";

The output of those are:

Holy Hole In A Donut, Batman!

Can someone explain to me how the XOR of those two strings produce that line of output?

Answer 1

According to this official example, using XOR on strings will operate on ASCII values of each respectly character, so in your example:

• B ^ \n = 66 ^ 10 = 72 = H;
• e ^ \n = 101 ^ 10 = 111 = o;
• e ^ \t = 101 ^ 9 = 108 = l;
• ...

3v4l result