adapt BSGS alg for eliptic curve secp256r1

[Xpeppo]

Hi, I'm trying to adapt BSGS alg for eliptic curve secp256r1

I already set up the proper a,b,p,n, and G points

I saw on your discussion in another forum that the "reduction" in Montgomery maths needs to be rewritten, you talked it was necessary to perform 9 reduction steps instead of 2 in Montgomery reduction - what that it means?

I understand the Reduction function is in Point.cpp file

void Point::Reduce() { Int i(&z); i.ModInv(); x.ModMul(&x,&i); y.ModMul(&y,&i); z.SetInt32(1); }

Performing 9 reduction instead of 2, means to call 9 times this function? Or rather to change the x.ModMul(&x,&i); y.ModMul(&y,&i); part, by adding 9 times those operations (So repeat 9 times the x and y.ModMul ?

I would appreciate your help to have this working for secp256r1 curve regards

[sky59]

I was not here some time....

What you write it means you are a beginner. So I attach for you linux version bsgs. You need to change permittions, run it on Ubuntu 20.04
You can test it with attached file txt

I know you and also me need private key for green pass. If you have one or manage to get one I give you also source code.
It is much more changes than just Montgomery reduction. There are some constants in the program also which needs to be changed

I adapted it only for CPU, forget GPU - this is still for K1 curve.

Wed, 05 Jan 2022 18:00:22 +0000 (UTC) - "sky59/Kangaroo-254-bit" **@.*>

Hi, I'm trying to adapt BSGS alg for eliptic curve secp256r1

I already set up the proper a,b,p,n, and G points

I saw on your discussion in another forum that the "reduction" in Montgomery maths needs to be rewritten, you talked it was necessary to perform 9 reduction steps instead of 2 in Montgomery reduction - what that it means?

I understand the Reduction function is in Point.cpp file

void Point::Reduce() {
Int i(&z);
i.ModInv();
x.ModMul(&x,&i);
y.ModMul(&y,&i);
z.SetInt32(1);
}

Performing 9 reduction instead of 2, means to call 9 times this function? Or rather to change the
x.ModMul(&x,&i);
y.ModMul(&y,&i);
part, by adding 9 times those operations (So repeat 9 times the x and y.ModMul ?

I would appreciate your help to have this working for secp256r1 curve
regards

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