-- L15 Algorithm (CSPRNG) --

o Complex KSA; a necessary requirement is complex relationship between the
  key and the output sequence. KSA also properly scales the key upto the
  expectedly larger 256-byte internal state.
o Tests indicate there are no weak keys (unlike original ARC4).
o The output sequence of L15 (scaled down version using L15P with 9 terms
  of internal state) is quite strange; it outputs an initial (large) quantity
  of data and then goes into a repetitive cycle. Tests with the scaled down
  version of L15 indicate that if there are any short cycles, they are very
  rare.
o Two unknown elements of the internal state are swapped per output reported
  (most of the time - original ARC4 swapped known/unknown).
o Original ARC4 had symmetric internal states (a problem) which is
  undoubtedly fixed in L15 due to different 65536 period permutation
  algorithm.
o Passes DIEHARD test-suite.
o Theoretically, L15 should be a one-way transformation (key->output)
  since for any possible key (e.g. smallest is 1-byte key) the internal
  state is scrambled/permuted at least twice and is therefore suitable
  for use as a digital-fingerprint algorithm.