1994-04-21 - Re: cryptophone ideas

Header Data

From: pcw@access.digex.net (Peter Wayner)
To: Phil Karn <karn@qualcomm.com>
Message Hash: b09b04899b567061acd16ce49d4f9d7f25c49daa76e9dd958459a4040e6b4095
Message ID: <199404212330.AA09243@access1.digex.net>
Reply To: N/A
UTC Datetime: 1994-04-21 23:31:10 UTC
Raw Date: Thu, 21 Apr 94 16:31:10 PDT

Raw message

From: pcw@access.digex.net (Peter Wayner)
Date: Thu, 21 Apr 94 16:31:10 PDT
To: Phil Karn <karn@qualcomm.com>
Subject: Re: cryptophone ideas
Message-ID: <199404212330.AA09243@access1.digex.net>
MIME-Version: 1.0
Content-Type: text/plain

>>They are capable of doing 2 data moves, a 16x16 multiply, a 40 bit
>>accumulate and a prefech of the next instruction all in 100ns.
>This is where a DSP really shines, since it's the fundamental
>operation in digital filtering; indeed it wouldn't be a DSP if it
>couldn't do a multiply/accumulate in a single clock cycle.
>But I wouldn't be too surprised if general purpose CPUs eventually get
>the same capability. And once they are, the distinction between a
>"DSP" and a "general purpose" CPU will pretty much vanish. DSPs are
>notoriously harder to program than general purpose CPUs, and being
>lower volume items they won't be able to compete in price or clock
>speed with general purpose CPUs made in the millions.


How hard is it to reprogram the DSP that comes with a cellular
phone right now? I've never opened one up. Can you just unsolder
a rom, read it, insert your own code for DH key exchange, add
some encryption, burn a new ROM and have a secure phone?