p – is the order of the finite subject
n – is the order of the group. Personal keys can vary from 1 (the generator level G) to n – 1.
All of the personal keys (Priv) lie in sure ranges of two.
2^a < Priv < 2^b
If we all know the a then after changing our personal key to the general public key (Pub), we will divide the Pub by 2, a instances to get Pub2 (utilizing elliptic curve divisions after all, PubOld * (2^(-1) mod n) = PubHalved ).
Priv2 can be the corresponding personal key to Pub2 and it’d appear to be:
1 < Priv2/(2^a) < 2
We all know for positive, that now we have 1 within the wholes place, and that it’s the solely digit now we have within the wholes place. Additionally If $Priv$ was an odd integer then there can be the identical variety of digits within the decimals place (in Priv2) as there have been divisions by 2 (on this case it’s a variety of digits).
But when Priv was a fair integer, then the variety of digits within the decimals place can be a minus the index variety of the division by 2 the place the corresponding personal key integer grew to become an odd quantity. Like if we had 250 as our Priv, then Priv2 would have 6 digits within the decimals place, as a result of 2^7 < 250 < 2^8, and it grew to become an odd quantity proper after the first division, therefore, 7 – 1 = 6
A particular case can be excellent sq. numbers, the place we might by no means get an odd quantity, besides on the finish, and that may be 1 as the ultimate division end result.
One other property, is that Priv2, if Priv is odd, would have both 75 or 25, as the two last digits at its finish.
Check out Priv = 247 for instance
2^7 < 247 < 2^8
After all of the divisions:
1 < 247/(2^7) = 1.9296875 < 2
Now suppose that we do not know the worth of the personal key. The issues that we all know are:
Integers a and b, 2^a < Priv < 2^b
There are 2 questions:
- Is there a technique to discover out the variety of digits of Priv2 (division end result) within the decimals place?
- How can we separate the final 2 digits on the finish of the decimal half, and discover out whether or not these are 25 or 75?
To think about the scenario higher, suppose that we’re making the calculations within the ℤp subject, and our curve is secp256k1
