RC4 Encrypt & Decrypt
RC4 is a stream cipher still found in older games and legacy formats. Like XOR it is symmetric, so one operation both encrypts and decrypts.
The RC4 key from the game files
Intended for your own single-player save files. Editing saves in multiplayer or online games breaks their terms of service and can get your account banned. Always keep a backup of the original file before you change anything.
RC4 is symmetric, so the same key both encrypts and decrypts. It is cryptographically broken and banned from modern protocols, but still turns up in older games.
Frequently Asked Questions
Is RC4 secure?
No. Serious biases in its keystream have been known since 2001, and it was banned from TLS in 2015. It survives only in legacy software — treat anything protected by RC4 as readable by anyone who wants to read it.
How is RC4 different from XOR?
Both XOR the data against a keystream, but RC4 generates a long pseudo-random stream from the key rather than repeating the key itself. That removes the repeating pattern that makes plain XOR so easy to break, though RC4 has its own weaknesses.
Can the key be recovered like an XOR key?
Not with the tools here. RC4 does not repeat its keystream in the way plain XOR does, so crib dragging and frequency analysis do not apply. You need the actual key.
Does key length matter?
RC4 accepts keys from 1 to 256 bytes and mixes the whole key into its state. Longer keys are stronger in principle, but the cipher's structural weaknesses remain regardless of length.