It is very special and very bad realization - store key around value.
Encrypted search can find any xor operation. Does not matter how and were stored key.
For this games exist very simple check:
Need two pair with value in memory and value in game. Like this:
Calculate xor for each row:
9559 xor 453963 = 444444
9459 xor 453871 = 444444
We get same value then it mean used xor with this value.
Now we can simple calculate need amount for set:
1234567 xor 444444 = 1318555
We set to memory 1318555 and get in game 1234567.
If we see value 444444 near our value we can set to 0 it.
number xor 0 = number
After that you can set value in memory same as in game.
But this happens only if game dev stupid enough. In most cases key stored in different place or written in code.