Bitcoin uses a specific elliptic curve

Bitcoin uses a specific elliptic curve and set of mathematical constants, as defined in a
standard called secp256k1, established by the National Institute of Standards and Technology
(NIST). The secp256k1 curve is defined by the following function, which produces
an elliptic curve:

y 2 = (x 3 + 7)over(? p)

or

y 2 mod p = (x 3 + 7) mod p

The mod p (modulo prime number p) indicates that this curve is over a finite field of
prime order p, also written as ? p, where p = 2256 - 232 - 29 - 28 - 27 - 26 - 24 - 1, a very large
prime number.