Cryptography
Symetric
RC4

RC4

RC4 is a fast stream cipher known to be very insecure.

Attacks

  • FMS Attack - Wikipedia CryptoHack

    Allows to recover the key from the keystream when RC4’s key is in the form (nonce || unknown). Mostly used to recover WEP from WEP SNAP headers. An implementation and description of this attack can be found on GitHub.

    If you have an encryption (or decryption, it’s the same) oracle, I recommend reading the writeups from this CryptoHack challenge.