|Bill Allombert on Sat, 02 Apr 2011 19:16:49 +0200|
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|Re: ECC modelling|
On Sat, Apr 02, 2011 at 04:29:06PM +0200, Bill Allombert wrote: > On Sat, Apr 02, 2011 at 04:41:43PM +0300, Eugene N wrote: > > Hello Sirs > > > > I am a student and i recently decided to use this renound tool for the > > purpose of ECC modelling. > > I browsed through the manuals & did some web searcehes ( > > http://orion.math.iastate.edu/cbergman/crypto/pari/parihelp.html) > > and i am very happy to discover this great tool. > > > > However, i stumbled upon some problems, wich made me turn for advice to > > expirienced users like you. I hope you will clear som things for me. > > > > I am looking for a way to generate n-nomials (generators of m.gr. inGF(2^m) > > ), especially tri-and pentanomials. I have read about ffinit(p,n) - but it > > produces > > long polies. > > There are no functions in PARI to generate irreducible trinomials or pentanomials. > but you can program it in GP easily: > > trino(N)=for(i=1,N-1,P=x^N+x^i+1;if(polisirreducible(P*Mod(1,2)),return(P))) > penta(N)=forvec(v=vector(3,i,[1,N-1]),P=x^N+1+sum(i=1,3,x^v[i]);if(polisirreducible(P*Mod(1,2)),return(P))) Actually I meant to write penta(N)=forvec(v=vector(3,i,[1,N-1]),P=x^N+1+sum(i=1,3,x^v[i]);if(polisirreducible(P*Mod(1,2)),return(P)),2) Both are correct but the second is faster. Cheers, Bill.