Like a lot of people, I often get angry when I read US patents. At best, I'll get confused or bored. Tonight, probably for the first time ever, I found comic relief in the otherwise sterile pages of a patent. Check out US Patent 5,345,508, "Method and Apparatus for Variable-Overhead Cached Encryption", by Lynn, Zweig and Mincher, assigned to Apple Computer, issued September 6, 1994. These guys have patented the notion of reusing one-time pads. That's right, reusing one-time pads! To "cut the computational overhead", they say, they generate a PN sequence once and then reuse it by XOR with successive packets until a "use limit" is reached. Quoting: "When the maximum count value specifies that the PN sequence is to be used only once, the security afforded by the present invention will be high, but a new PN sequence must be generated for each message sequence transmitted and so the computational overhead will also be high. If the maximum count value specifies a maximum count value [sic] greater than one, the PN sequence stored in the cache will be reused to encrypt the maximum count number of message sequences. The resulting ciphertext messages will be more vulnerable to statistical cryptoanalytic attack as the maximum count value increases..." No shit! Talk about missing out on some absolutely fundamental concepts... There may actually be a silver lining to this utterly silly patent. Although I've only looked it over briefly, it seems to unintentionally cover the TIA's so-called voice "privacy" technique for TDMA digital cellular -- i.e., generating a pseudorandom sequence at the beginning of a call and then reusing it for every frame. Maybe Apple could be persuaded to agressively sue everybody so cellular will switch to *real* encryption... :-)