[RC5] My contribution to RC5

Phil Gregory pgreg430 at neors.cat.cc.md.us
Sun Apr 5 20:31:10 EDT 1998


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> If I wanted to send something secret, then as the final stage before encrypting
> it, I would compress it into some format with no header information whatsoever.
> How would you handle cracking that efficiently?

That's a good idea, since compression also does a nice job of distributing
patterns across the entire file, making pattern analysis fairly fruitless.
However, you need to get the message from you to the recipient, and most
programs use headers of some sort to determine how and by what transport
the message is to get there.  In addition, I believe that compressed files
generally have headers, too.  The compression would probably slow someone
down, especially if they didn't know that it was compressed, but it
probably still wouldn't stop a determined person.

                                ---------------
int a=10000,b,c=2800,d,e,f[2801],g;main(){for(;b-c;)f[b++]=a/5;for(;d=0,g=c*2;c
- -=14,printf("%.4d",e+d/a),e=d%a)for(b=c;d+=f[b]*a,f[b]=d%--g,d/=g--,--b;d*=b);}

                                ---------------
                                 Phil Gregory
                                     DNRC
                              phil_g at geocities.com
                        -------------------------------
            (Finger pgreg430 at neors.cat.cc.md.us for my public key.)


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