Adam Back wrote:
Re comments that I should re-read the paper, here is what Wiener's paper says about estimated costs of a specialized DES key breaker:
$100,000 for a machine to break DES in an average of 35 hrs $1 mil for a machine to break DES in an average of 3.5 hrs $10 mil for a machine to break DES in an average of 21 mins
It was as Peter says published in 1993.
Wiener also budgets for $500,000 in design costs (wages, parts, fab etc).
Another interesting part of the design is that it is based on a pipelined chip, clocked at 50Mhz which can try 50 Million keys/sec.
35 hours sounds a reasonable amount of time to break a Swift banking transfer key protecting trillions of dollars of funds.
One thing that I haven't heard anybody mention yet is that if time is important, you can break keys in an arbitrarily short period of time, if there's a continuous sequence of transactions. Assume it takes 35 hrs to crack a key (with 50% probability), This means that you have a 1.4% chance to crack it in one hour. If you give up after an hour and pick a new transaction to crack, you have a 50% chance of cracking at least one transaction after 48 hours, and they will all have been cracked in less than an hour. -- What is appropriate for the master is not appropriate| Tom Weinstein for the novice. You must understand Tao before | tomw@netscape.com transcending structure. -- The Tao of Programming |