International Association
for Cryptologic Research

We find statistical weaknesses in 20 RC-4 like algorithms including the original RC4, RC4A, PC-RC4 and others.

This is achieved using a simple statistical test.

We found only one algorithm which was able to pass the test - VMPC-R.

This algorithm, being approximately three times more complex then RC4,

is probably the simplest RC4-like cipher capable of producing pseudo-random output.