RC4
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In cryptography, RC4 is a stream cipher. While it is remarkable for its simplicity and speed in software, multiple vulnerabilities have been discovered in RC4, rendering it insecure. It is especially vulnerable when the beginning of the output... Wikipedia
First published: Leaked in 1994; (designed in 1987)
Key sizes: 40–2048 bits
Rounds: 1
Speed: 7 cycles per byte on original Pentium; Modified Alleged RC4 on Intel Core 2: 13.9 cycles per byte
State size: 2064 bits (1684 effective)