>>994452
If it's not a one time pad (that means the key is at least the same length as the message and completely random), xor encryptions are shit. Otherwise they're literally unbreakable.
For example, let's assume we know your message is plain english ascii text. Then all most significant bits in the message are zero. If the key is shorter than the message, this results in a repeating pattern in the ciphertext's most significant bits, which tells your key's length and also is the key's most significant bits, no calculations needed. Also in plain ascii english, the second most significant bits of the message is likely but not guaranteed to be one. The corresponding bits in the ciphertext might not be a repeating pattern, but as the key's length is already known, we can spot anomalies easily. These anomalies are most likely spaces, punctuation, and digits. So we can tell words apart. The third most significant bits are likely to be one, unless you write your messages in all caps. The fourth most significant one can be deduced using statistics as letters aren't occuring equally frequently. Half your key is broken at this point. The rest can be bruteforced by checking if decryption results in meaningful words.
If your message is not plain ascii text but some binary file, we can hope that your file contains a sequence of equal bytes (for example, a null padding somewhere), which may result in a repeating pattern if it is longer than the key.
I'm sure there are more ways to crack xor encryption but I'm just an uneducated nobody on the internet.