Quote from: _Counselor on Today at 05:23:08 PM

Quote from: digaran on Today at 04:56:07 PM

Just to share something I found out, so if you for example divide a point by 35, and then add 1 G to your point and divide the +1 of your point by 35, what do you think will happen?
Well the results of both divisions will have a distance equal of n/35, so if you after dividing p/35, start adding n/35 to your result, for each addition you'd get the result of +1p/35, add n/35 twice, you'd get +2p/35.

Do not fix on EC points, elliptic curve is just "graphical" interpretation of a numbers, all maths behind it works at finite field and obey all laws of "real" numbers math.
If you divide any "real" number by 35, then divide number+1 by 35, then difference between results will be 1/35. This is also works in finite fields and for EC points.

Quote from: digaran on Today at 04:56:07 PM

of course if after adding 9 to p, your k ends with 5, then dividing by 5 adding 9/5 won't give you the right key, that's how you can determine what the last digit of your k is.

This is not true, for example - 26/5 = 5,2; 35/5 = 7; 9/5 = 1,8. 26/5+9/5 = 5,2+1,8 = 7 = 35/5
you can also check this with EC points like:

Code:

p95 = curve.fromPrivate(9).div(5)
p265 = curve.fromPrivate(26).div(5)
p355 = curve.fromPrivate(35).div(5)
print(p265, p355)
print(p265.add(p95))

output:

Code:

03F18D7188F16C93BB251A68DE95A057E02356BA0602854041BA4E170676E54169 025CBDF0646E5DB4EAA398F365F2EA7A0E3D419B7E0330E39CE92BDDEDCAC4F9BC
025CBDF0646E5DB4EAA398F365F2EA7A0E3D419B7E0330E39CE92BDDEDCAC4F9BC

Ok, but did I say otherwise? If we add 9 to 26 we get 35, dividing 35/5 = 7 + 9/5 = 8.8, and 8.8 is the wrong answer.

As I said if our k ends with 5, adding 9/5 to result returns wrong key.
And of course that when we are working with secp256k1, we are dealing with a prime and mod n.

Ps, I am really uneducated totally, I just share my experience, please nobody take my posts as if I am arrogant, I am 0.00000001 while everyone here is beyond 100.🙂