RC4
Rivest Cipher 4
A deprecated stream cipher with known weaknesses.
Rivest Cipher 4 is a fast stream cipher once widely deployed in protocols such as WEP, early TLS, and WPA with TKIP. It is now deprecated because of serious biases in its keystream that enable practical attacks and plaintext recovery, and its use in TLS has been prohibited. Recognizing RC4 as insecure and knowing it should be replaced by modern ciphers like AES is a common exam objective. Its presence in WEP is a major reason that standard fell.
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Looking RC4 up is step one. Getting tested on it is step two.
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