Quote from: j2002ba2 on August 11, 2022, 05:18:23 PM

Quote from: SamYezi on August 11, 2022, 12:25:17 PM

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I got it, and your suggestions are useful. I changed the code here and on Github. However It still doesn't work for small numbers (See the test case 1)
https://github.com/MaltoonYezi/Python-DSA/blob/main/Cryptography/SECP256k1Procedural.py
Sorry, for a delayed response

You got mistaken somewhere (or, as usual, in many places).

Test case 1 asks us to multiply (47,71) by 8 modulo 223 (with a=0, b=7). However with this prime the curve has structure 42x6, it is noncyclic. Point (47,71) is from the group of (7,166); while (49,71) is from the group of (8,127). So, you could never reach either point from the other one.

You might want to change the test. If you insist on modulo 223, then b=5 is a good choice. Otherwise (b=7) use modulo 67 or 79, they are a bit like p and n in secp256k1, modulo one of them the group size is the other.

Yeah that's a good idea. However these test case 1 values I took from the book, and I checked the values once again and the problem was that the right values in the comments were incorrect. Now that I've refactored the script, it works fine. Also, Public keys outputs are being correct as well.
Thanks for your tips!