Legend for OpenSSL’s dhparam output

I was curious to find out the meaning of all the dots, pluses and stars that openssl dhparam outputs while computing Diffie-Hellman parameters.

To make a long story short, here’s the legend:

• . : A potential prime number was generated.
• + : Number is being tested for primality.
• * : A prime number was found.

 

Reference:

http://openssl.org/docs/crypto/BN_generate_prime.html#DESCRIPTION

http://www.google.com/codesearch/p?hl=en#RPhFhNy2eoY/openssl-0.9.8b/apps/dhparam.c&q=DH_generate_parameters%20package:%22http://www.openssl.org/source/openssl-0.9.8b.tar.gz%22&l=541