Primo is a primality proving software based on the ECPP (Elliptic Curve Primality Proving) algorithm. Given positive odd integers, it tests whether these integers are prime, and if they are it produces primality certificates. With Primo, one can check crypto-primes and prove whether they are actually prime... or not.

Executable for Linux 64-bit (Ubuntu 18.04/x86-64 architecture)
Compiled with Free Pascal 3.0.4 and Lazarus 1.8.2
Primo screenshot

A short description of the ECPP algorithm can be found at Elliptic Curve Primality Proving by Eric Weisstein (from MathWorld — A Wolfram Web Resource).


• What does "LX64" stand for?
Linux 64-bit.

 • Does it exist a Primo version for an other operating system than Linux?
No, there is not and there will not be. (Why would I pay for an OS? Linux is free.)

• Is the LX64 version for multicore processors?
Yes, it is. It can work with up to 64 processors.

• Does the LX64 version run with Linux distributions other than Ubuntu 18.04?
It should do (but I do not know).

• Does it exist a command line version?
No, there is not and I do not plan to write a one.


ECPP records set with Primo since 2001.


v4.3.3 (December 12, 2020)
• Candidates up to 50,000 decimal digits (instead of 40,000).

 Previous changes


The software Primo may be used free of charge but it might be a good idea to read the End-User License Agreement before downloading and using it.

It is impossible to resume with the 4.3.3 version a certification started with a version prior to 4.3.0.

 primo-433-lx64.7z   (31.3 MB, binary files)