25 Feb 2019

  Code related to the BN_GENCB callback interface updated for compatibility with openssl-1.1.1
  Added more error checks on the return values from various BN routines.

7 June 2017

  Made callback() function static.

31 May 2017

  Added interface to BN_mod_inverse()

30 May 2017

  Updated some of the comments in bignum.c
  Added some more tests to test.py

29 May 2017

  Now includes the optional arguments and callbacks.
  Added cleanup calls to BN_free() and BN_CTX_free().

27 May 2017

  Initial version.
  Does not include BN_generate_prime_ex() optional args: safe, add, rem, cb.
  Does not include BN_is_prime_ex() optional args: nchecks, cb.