ref: 75186be2c2aa5566f3c490e087c24e12c872216e
dir: /sys/src/libsec/port/secp256k1.mp/
# E: y² = x³ + ax + b secp256k1(p,a,b,x,y,n,h) { p = 2^256 - 2^32 - 2^9 - 2^8 - 2^7 - 2^6 - 2^4 - 1; a = 0; b = 7; x = 0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798; y = 0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8; n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141; h = 1; }