Foundations of Blockchain

Point doubling

Point doubling is a similar operation to point addition, with the exception that point Q is moved to the same location as point P (P = Q):

Figure 2.8: Point doubling of P

The following steps are performed on the elliptic curve as shown in Figure 2.8 to compute point doubling:

1. Draw a tangent (since there is only one point) to the curve at point P
2. This line will intersect the curve at point R¹
3. A reflection of point R¹ about the x axis gives point R, and this is point doubling or a multiple of R (2R)

Point doubling is the concept used in ECC to construct the public key from the private key. The following section explains in depth ...