Primo is a primality proving program 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 14.04/x86-64 architecture)
Compiled with Free Pascal 2.6.4 and Lazarus 1.2.2
Primo for Linux 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.
  • Is the LX64 version for multicore processors?
    Yes, it is. It can work with up to 48 processors.
  • Does the LX64 version run with Linux distributions other than Ubuntu 14.04?
    It should do (but I do not know).
  • Does it exist a command line version?
    No, not yet.

Some running times
The following certification running times were obtained with Primo using an Intel i7-2600 3.4GHz processor.

NSieve parametersTasksRunning time
10999 + 72000 dd23 bits851.44s
101999 + 73212000 dd23 bits814mn 8s
102999 + 18873000 dd24 bits81h 7mn
103999 + 47714000 dd25 bits8     4h 5mn [1]
104999 + 226695000 dd26 bits88h 45mn
105999 + 293796000 dd27 bits819h 25mn

[1] This number is the third ECPP record set with Primo. Its certification, thirteen years ago, took 2856h!

v4.1.1 (January 4, 2015)
  • Maximal size of candidates increased up to 116224 bits (35000 decimal digits).
  • Number of possible concurrent tasks increased up to 48.
  • Added new discriminants.
  • Modified the factorization of polynomials. It now requires a little less memory.
  • Added double-eta quotient invariants in order to compute class polynomials with smaller coefficients. (It is almost sure now that the patent WO/2005/004383 will not be granted, at least the claims 1, 2, 3, and 6.)
 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.

Though this is possible, it is not advised to resume with this new version a certification started with a previous version.

  primo-411-lx64.7z    19.3 MB   Executables  (binary files)

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