Bitcoin uses a specific elliptical curve, and the domain parameters used in the curve are defined in the secp256k1 standard. This curve is represented by the following cubic equation in a finite field of prime order p:
y2 mod (p) = x3 + 7 mod (p)
Figure 2.10: secp256k1's elliptic curve over real numbers
As the name suggests, secp256k1 can have a key size of up to 256 bits. The details of the domain parameters used by secp256k1 are represented in hexadecimal strings and are as follows:
- Large prime numbers are used in the finite field.
- p = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F ...
