John M wrote:
Well, what about spreading the information out? Something simple like doing a matrix rotation on the scrambled data in 8 byte blocks and splice it by bit to split the data up, add ECC (error correction code) to it, and spread it to several servers. This way no one server has all the information necessary to recreate the "offending" information and if one server gets "hit" (killed), the information can still be regenerated from the the information and ECC from the other servers.
This seems like another variation of the 'reverse secret-sharing' schemes, independently proposed by Jim McCoy, Matt Ghio, and others. Cooper and Birman give a good theoretical introduction at http://cs-tr.cs.cornell.edu/TR/CORNELLCS:TR95-1490 although their scheme uses only the simple XOR instead of a full matrix. Ghio's version is at http://infinity.nus.sg/cypherpunks/dir.archive-97.06.12-97.06.18/0391.html Neither paper goes heavily into linear algebra, but the scheme can easily be extended to martices in a finite field, xor being the special case of mod 2. The idea's been around for awhile; it'd be nice to see a working implementation (hint, hint).