Actually... It only needs to do this once with the correct key :) Problem is calculation would take too long or take too much code-space. Anyway it wouldn't work :/ KreAture ----- Original Message ----- From: "Wagner Lipnharski" To: Sent: Thursday, January 16, 2003 1:04 AM Subject: Re: [PIC]: Fastest possible 512 bit multiply ??? > Kyrre Aalerud wrote: > > Does anyone have any examples on fast 512 bit multiplication ? > > I'm talking about 512bit x 512bit. > > > > Is there any PIC's that have a MULT operation easing this ? > > > > KreAture > > > I think there is no much to speed up the usual > > shift > if carry bit then do a 64 bytes ADD > decrement 512 loop counter > do it again. > > The worst case of all 512+512 bits ON, will take a total of > 1024 shifts + 32768 adds, generating a 1023 bits number. > > Gross numbers on an AVR (with enough internal RAM), would take around 80k+ > instructions (also clock cycles), if running at 8MHz, would take aprox 10ms > to complete the multiplication. If thinking about descrambling some > encription code, it will do around 100 calculations per second, less than 9 > million calculations a day. Considering the permutarion of 512 bits > encription, it can take almost 40 years to complete the whole range... :) > > Wagner. > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.