[RC5] ECCp-97 Result Found

Tim Charron tcharron at ctfinance.com
Fri Mar 20 09:35:06 EST 1998


> The Certicom ECCp-97 Challenge has been completed already, after 
> only 40% of the possible distinguished points were located.

They solved the problem after finding 187000 DPs.  There are 
actually 1073741824 possible DPs.  After finding 450000, you would 
have a 50% chance of having a "collision" which means you've solved 
the problem. After only 187000 points, the chance of a collision 
occuring is only 16%.  They got quite lucky.

The Distinguished point mechanism is based on the "birthday paradox". 
 As people enter a room, you record their birthdays.  How many people 
must enter the room before a duplicate birthday is recorded?  
While we are guaranteed a match after 365 people, only 23 people are 
required to have a 50% chance of finding a match.

-- Tim
Tim Charron
tcharron at ctfinance.com
tcharron at interlog.com
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