Then can I select as interval whole 256 bit space (0000000....fffffffff....) and to leave it running forever?
Then I start to doubt if bsgs algo is somehow useful?
BSGS is supposed to be used when you know a private key is between a minimum and maximum value, of course it is not efficient if you don't have a bounding range because 256-bit space is too large to search.
OOOOOPS!
I just realized I have not finished yet!
Yes, Montgomery math is ok, also reading 149 public keys is confirmed they lie on the r1 curve, it is simple test that y*y=x*x*x+a*x+b for each public key
But for k1 a=0 and b is 7, so I think I have to "unoptimize" points add, double functions to count also with a*x and b as I did for entry public keys test
Does this mean you basically forgot to add terms for "a" (which is 0 for k1)?
But I do not understand what is the z-coordinate of a point. Does anybody know? JLP surely knows but can I contact him somehow?
EDIT: It seems z is the sign of y coordinates?
Also, probably a, b will not have any impact on point addition but only on point doubling where a is coming into calculations
It seems b does not have any effect on points arithmetic? It doesnot come into any calculations?...
JLP must has disappeared so it's unlikely you can reach him.
Warning - rocket math ahead
"Guide to Elliptic Curve Cryptography" (DOI 10.1.1.394.3037) says that Z is the third of a set of three Jacobian (the book calls them projective) coordinates (so X,Y, and Z) coordinates which can be "transformed" from normal - affine, in book terminology - (x,y) coords. i.e. from the elliptic curve in 3D to 2D.
So basically:
y2 = x3 + ax + b -- this we already know.
Apprently, it can also be represented as Y
2Z = X
3+aX Z
2 +bZ
3 (according to example 3.19, page 87).
So the Z is probably anything that reduces the above to "y2 = x3 + ax + b" - so it's always 1, in other words. Not sure why you think you need the Z coord though, it's not necessary for r1.
If you ever manage to get a copy of the book (whether by google search or just through sci-hub) you'll also be able to see this info for yourself.