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# Primo

Workload type |
ECPP |

First release |
2001-08-03 |

Latest version |
4.3.2 2020-02-06 |

**Primo** is a computer program which tests numbers for primality using the Elliptic Curve Primality Proving (ECPP) algorithm, the fastest known general-purpose primality testing algorithm. Primo is developed by Marcel Martin using Free Pascal and Lazarus IDE.

The program does not require a number to be of any specific form. If a number is found to be prime, a primality certificate is produced, which can be quickly verified.

The record largest prime certified using Primo (as of Feb 2020) is Partition(1289844341), it has 40,000 digits. The certification of this number was done by Paul Underwood with Primo 4.3.0. The certification process took 21.5 months using a 4 x 12 core AMD 6174. The Factoring Database allows users to upload Primo certificates.

## See also

- ECPP-DJ - an open-source implementation of ECPP test, which can also verify certificates generated by Primo.