secp256k1 is a Koblitz elliptic curve used with ECDSA for digital signatures. It gained major traction after Bitcoin selected it instead of NIST curves. section 7.3.3
Its curve equation is y² = x³ + ax + b, with a = 0 and b = 7. Coordinates use arithmetic modulo the prime p = 2²⁵⁶ − 2³² − 2⁹ − 2⁸ − 2⁷ − 2⁶ − 2⁴ − 1, forming a group of prime order. section 7.3.3
Key parameters include:
- The generator G has fixed coordinates x = 55066263022277343669578718895168534326250603453777594175500187360389116729240 and y = 32670510020758816978083085130507043184471273380659243275938904335757337482424. section 7.3.3
- Koblitz constraints allow implementations to optimize some curve operations. section 7.3.3
