https://www.bloomberg.com/news/articles/2019-04-23/first-golden-cross-for-bitcoin-in-3-years-as-bulls-return-chart

First Golden Cross for Bitcoin in 3 Years as Bulls Return

Here’s yet another sign the crypto winter is thawing. Bitcoin, the largest digital currency, has formed its first bullish golden cross since October 2015, according to Bitstamp pricing that includes weekend moves. The milestone follows a 35 percent rally for Bitcoin past $5,600, on track for its best monthly gain since the height of the crypto frenzy in December 2017. The sudden resurgence has also been apparent in other parts of the market, including record contract trading volumes in the futures market at CME Group Inc. earlier this month.

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.