Secret splitting

A few days ago I resurrected all my files from a desktop system I haven’t used for almost six years. Below is my implementation of secret splitting as described in Bruce Schneier’s book “Applied Cryptography, 2nd edition”.

The idea is basically: generate a random keystream, xor the plaintext with the random keystream, use separate couriers and send the random keystream and the ciphertext to the final destination using separate routes, and finally combine the random keystream with the ciphertext to recreate the plaintext. None of the couriers know which piece they are carrying.

To improve this idea would be to generate more than one random keystream, xor the keystreams and the plaintext, thus requiring more couriers and different routes for each datastream.

And, by the way, xor crypto isn’t really that strong. Continue reading Secret splitting

endofepoch.c

Jeg børstet støvet av noen tilårskomne filer forleden dag. Jeg fant et lite program som jeg skrev en gang i 2000. Programmet teller ned til slutten av Unix-epoken.

Den opprinnelige definisjonen av datatypen time_t, 32-bit heltall med fortegn, vil få overflyt i midten av januar 2038. Moderne 64-bit OS som FreeBSD/amd64 9.0 har for lengst gått over til 64-bit time_t. Bare ta en titt i fila /usr/src/sys/amd64/include/_types.h, omtrent ved linje 83. Problemet med overflyten i år 2038 vil fortsatt gjelde alt utstyr og (binære) filformater som bruker den gamle definisjonen, slik som FreeBSD/i386 9.0. Ta en titt i fila /usr/src/sys/i386/include/_types.h, omtrent ved linje 91. Den engelske utgaven av Wikipedia har en utfyllende artikkel om problemet.

Kildekoden for det søte, lille programmet mitt, er gjengitt under. Continue reading endofepoch.c

Are you prepared for the World IPv6 Launch on June 6, 2012?

Last year we had the World IPv6 Day on June 8, 2011. This year we’ll have the World IPv6 Launch on June 6, 2012.

According to this joint press release by Akamai Technologies, Inc., AT&T, Cisco, Comcast, D-Link, Facebook, Google Inc., Internet Society, Internode, Limelight Networks, Microsoft Bing, Time Warner Cable, and Yahoo!:

Major Internet service providers (ISPs), home networking equipment manufacturers, and web companies around the world are coming together to permanently enable IPv6 for their products and services by 6 June 2012.

The hard question is: Are you prepared? Continue reading Are you prepared for the World IPv6 Launch on June 6, 2012?