A recursive primality certificate for a prime . The certificate consists of a list of
1. A point on an elliptic curve
for some numbers and
.
2. A prime with
, such that for some other number
and
with
,
is the identity on the curve, but
is not the identity. This guarantees primality
of
by a theorem of Goldwasser and Kilian (1986).
3. Each has its recursive certificate following it. So if the smallest
is known to be prime, all
the numbers are certified prime up the chain.
A Pratt certificate is quicker to generate for small numbers. The Wolfram Language
task ProvablePrimeQ[n]
in the Wolfram Language package PrimalityProving`
therefore generates an Atkin-Goldwasser-Kilian-Morain certificate only for numbers
above a certain limit ( by default), and a Pratt
certificate for smaller numbers.