🚀 go-pugleaf

In the FAQ (Thanks to Larry Loen for this... it is informative...), the
following is stated about pseudo one time pads:

  There are a variety of cipher systems which generate "pseudo
  one time pad" streams of cipher key, but all have the same
  theoretical vulnerability; any algorithmic process introduces
  relationships between some old key bit(s) and the new key bit
  and so permits cryptanalysis.  "Random number generators" are
  frequently dreamed up by newcomers as a "pseudo one time pad",
  but they are notoriously vulnerable to analysis, all
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  independent of whether the pseudo-random stream satisfies
  randomness tests or not.

My question is, why?  Now before I get roasted & told to "read the
literature..." and "your an idiot...", I have read the literature.  I've
also spent a considerable amount of time working with/analysing pseudo
random number generators (PRNGs).  It seems to me that, if your source is
sufficiently random (ie. NOT some type of feedback shift register or linear
recurrence equation, but something random in a cryptographic as well as a
statistical sense), and you follow the one time rule (ie. only use any key
ONCE - never encrypt 2 files with the same key), this should be pretty
secure.  For example, would the following be "vulnerable to analysis"?

1) DES a file of ASCII 0's (of the same length as the plain text) with
some key - this gives you a pseudo-random bit stream.

2) XOR this with the plain text ---> cipher text.

This is pseudo one time pad that I don't think would be "easy" to break.
Now, how about substituting some other type of PRNG for DES?  If its
non-predictive (can't determine numbers in the stream from other numbers)
and statistically random, whouldn't it work?  Is the real problem coming up
with a "good" enough PRNG?

Thanks for the help...

Dane Butzer

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