H Melua

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Posts: 172

posted 10 years ago

Hi

I'm stock with polynoms! Assuming that I have this polynom in hex 0xA

and

I tried doing it this way, but thats not really working!

As doing normal division, The max power of the polynom (can but) will never be greater than 0x10

What changes do i need to make to get the reminder?

Thanks

HannaH

[ November 12, 2007: Message edited by: H Melua ]

I'm stock with polynoms! Assuming that I have this polynom in hex 0xA

and

**I want the remainder of dividing**it by 0xB then how would I present this in java?I tried doing it this way, but thats not really working!

As doing normal division, The max power of the polynom (can but) will never be greater than 0x10

What changes do i need to make to get the reminder?

Thanks

HannaH

[ November 12, 2007: Message edited by: H Melua ]

Peter Chase

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Posts: 1970

posted 10 years ago

Given that no-one else has replied, I suspect they all thought "WTF?", like I did.

I think you're assuming that these "polynomial algorithms" are something well-known. But it doesn't look like anything I've ever seen and I did a fair amount of numerical computing.

Please give some more background, then maybe we can help.

(Yes, I do know what a "polynomial" is, but that doesn't seem to help much in understanding your code.)

I think you're assuming that these "polynomial algorithms" are something well-known. But it doesn't look like anything I've ever seen and I did a fair amount of numerical computing.

Please give some more background, then maybe we can help.

(Yes, I do know what a "polynomial" is, but that doesn't seem to help much in understanding your code.)

Betty Rubble? Well, I would go with Betty... but I'd be thinking of Wilma.

Nicholas Jordan

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Posts: 1282

posted 10 years ago

Perhaps try modulo operator - why otherwise ?

**[original poster:]I want the remainder of dividing**

Perhaps try modulo operator - why otherwise ?

"The differential equations that describe dynamic interactions of power generators are similar to that of the gravitational interplay among celestial bodies, which is chaotic in nature."

H Melua

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Posts: 172

posted 10 years ago

Peter

Thanks for replying...

you see its not something people are likely to do in their daylife!! its all about cryptography, and in my BSc studies we didnt have to do any of it! And many people stop their academic studies at that stage... so i wasnt really thinking its well known (since even my friend Google didnt know! ), but i hoped some1 from the croud might know

Nick

Thanks to you too for replying...

But i dont know how to divide binaries (over Finite fields) to begin with

Thanks for replying...

you see its not something people are likely to do in their daylife!! its all about cryptography, and in my BSc studies we didnt have to do any of it! And many people stop their academic studies at that stage... so i wasnt really thinking its well known (since even my friend Google didnt know! ), but i hoped some1 from the croud might know

Nick

Thanks to you too for replying...

But i dont know how to divide binaries (over Finite fields) to begin with

H Melua

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Posts: 172

posted 10 years ago

In all cases, i've solved this issue using "over naive" method (i dont know if there exist a word in the dictionary thats worse than naive for me to use :roll: )

So thanks for looking

So thanks for looking

Nicholas Jordan

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Posts: 1282

posted 10 years ago

Try

Note that Bruce Schneier states there are no sufficient texts on crypto, and Springer papers are the only useable source. I just bought Modern Cryptography - Theory and Practice by Wenbo Mao, hp imprint and the author's approach takes a different tone but is substantively similar in it's cautionary admonishments. You can get most such titles at any library: I have asked and been told that this is what the interlibrary loan system is for. All they ask is that you do a reasonable search on your own first and they will obtain any book for you.

Do you want floating point bit-twisting or fixed point ?

There is no such thing as

What you need to do is make *EVERYTHING* BigInteger, and study crypto unabashedly:

I think we left-shift to mult, but there are sign-extension issues to study and there is also a limitation to the left-shift operator applied to an int that makes << 33 behave something like << 1 (see:0xffffffff leftShift 33 ? )

What is the formal title of your class (schoolastic) and your class (java) and do you intend to become a world-class cryptographer ?

"The differential equations that describe dynamic interactions of power generators are similar to that of the gravitational interplay among celestial bodies, which is chaotic in nature."

**[H Melua:] But i dont know how to divide binaries (over Finite fields) to begin with**

Try

*Using cyclotomic polynomials to construct efficient discrete logarithm cryptosystems over finite fields*at Springer Berlin / Heidelberg

Note that Bruce Schneier states there are no sufficient texts on crypto, and Springer papers are the only useable source. I just bought Modern Cryptography - Theory and Practice by Wenbo Mao, hp imprint and the author's approach takes a different tone but is substantively similar in it's cautionary admonishments. You can get most such titles at any library: I have asked and been told that this is what the interlibrary loan system is for. All they ask is that you do a reasonable search on your own first and they will obtain any book for you.

Do you want floating point bit-twisting or fixed point ?

There is no such thing as

**polynom in hex 0xA**: There are Polynomials | There are fields, variables, and several Number classes in Java, to do bit-ops, you will likely need to use primitives such as int, which I have seen bit-shifted in the sources for Java. I do not know if fp's could be manipulated.

What you need to do is make *EVERYTHING* BigInteger, and study crypto unabashedly:

*The work continues, in public, by anyone and everyone who is interested.*

**[H Melua:] //i think when we times by x, we actually shift to the right!?**

I think we left-shift to mult, but there are sign-extension issues to study and there is also a limitation to the left-shift operator applied to an int that makes << 33 behave something like << 1 (see:0xffffffff leftShift 33 ? )

What is the formal title of your class (schoolastic) and your class (java) and do you intend to become a world-class cryptographer ?

Arjen K. Lenstra1 - Citibank, N.A.,

(Cited Work) show how to use cyclotomic polynomials to construct subgroups of multiplicative groups of finite fields that allow very efficient implementation of discrete logarithm based public key cryptosystems. Depending on the type of application and implementation, the resulting schemes may be up to three times faster than the fastest known schemes of comparable security that use more conventional choices of subgroups or finite fields.

H Melua

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Posts: 172

posted 10 years ago

thanks "Very" "Very" much for that Nick...

I'll have a good read about this...

Its certainly not a straight-forward task..

Thanks alot for your time again

I'll have a good read about this...

Its certainly not a straight-forward task..

Thanks alot for your time again