🚀 go-pugleaf

Webbge@che17.ncsu.EDU (Greg Earl Webb) writes:


>I've seen some interesting posts here recently, but I have yet to
>see the topic of padding data with garbage.  It seems to me that
>if you had an algorithm that would not only encrypt the data, but would
>also insert random data into the original data (without following
>a regular pattern) that it would be almost impossible for someone
>to tell what was real information and what was just junk.  Although
>the size of the document would increase, the difficulty in decrypting
>the message would also increase considerably.

>The only problem I can see with this method is how do you insert data
>in a non-regular pattern and still have the ability to remove it later.
>Please comment on this type of procedure.  I'm sure people have thought
>on these lines before and would be interested in seeing what they have
>to say......

>			Greg Webb

A guy names William Simon (email address: alain@elevia.UUCP) posted
some stuff long ago about "braiding" messages. Essentially you took
two streams of data (a and b) and a pseudo-random source. Everytime a
1 came from the source you took a block of data from a and everytime a
0 came from the pseudo-random source you took a block of data from b.
Reconstructing a and b is possible if you have the same pseudo-random
bit stream. 

There were long debates about how easy it is to reconstruct this, but
Simon showed that it was equivalent to the one-time pad. (I believe he
assumed that a and b had "random" patterns. Obviously if a is all
zeros and b is all ones, then reconstruction is simple.) 

In the other direction, a fellow named Dave August once wrote a paper
for Cryptologia (circa 1987) about the technique of deleting random
letters from a plaintext message. The redundancy of English left the
message still readable.

-Peter
-- 
Peter Wayner   Department of Computer Science Cornell Univ. Ithaca, NY 14850
EMail:wayner@cs.cornell.edu    Office: 607-255-9202 or 255-1008
Home: 116 Oak Ave, Ithaca, NY 14850  Phone: 607-277-6678