Manual Pages for UNIX Operating System command usage for man DH_generate_parameters

OpenSSL                          DH_generate_parameters(3openssl)



NNNNAAAAMMMMEEEE
     DH_generate_parameters, DH_check - generate and check
     Diffie-Hellman parameters

SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
      #include 

      DH *DH_generate_parameters(int prime_len, int generator,
          void (*callback)(int, int, void *), void *cb_arg);

      int DH_check(DH *dh, int *codes);


DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
     DH_generate_parameters() generates Diffie-Hellman parameters
     that can be shared among a group of users, and returns them
     in a newly allocated DDDDHHHH structure. The pseudo-random number
     generator must be seeded prior to calling
     DH_generate_parameters().

     pppprrrriiiimmmmeeee_lllleeeennnn is the length in bits of the safe prime to be
     generated.  ggggeeeennnneeeerrrraaaattttoooorrrr is a small number > 1, typically 2 or
     5.

     A callback function may be used to provide feedback about
     the progress of the key generation. If ccccaaaallllllllbbbbaaaacccckkkk is not NNNNUUUULLLLLLLL,
     it will be called as described in BN_generate_prime(3) while
     a random prime number is generated, and when a prime has
     been found, ccccaaaallllllllbbbbaaaacccckkkk((((3333,,,, 0000,,,, ccccbbbb_aaaarrrrgggg)))) is called.

     DH_check() validates Diffie-Hellman parameters. It checks
     that pppp is a safe prime, and that gggg is a suitable generator.
     In the case of an error, the bit flags
     DH_CHECK_P_NOT_SAFE_PRIME or DH_NOT_SUITABLE_GENERATOR are
     set in ****ccccooooddddeeeessss.  DH_UNABLE_TO_CHECK_GENERATOR is set if the
     generator cannot be checked, i.e. it does not equal 2 or 5.

RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEESSSS
     DH_generate_parameters() returns a pointer to the DH
     structure, or NULL if the parameter generation fails. The
     error codes can be obtained by ERR_get_error(3).

     DH_check() returns 1 if the check could be performed, 0
     otherwise.

NNNNOOOOTTTTEEEESSSS
     DH_generate_parameters() may run for several hours before
     finding a suitable prime.

     The parameters generated by DH_generate_parameters() are not
     to be used in signature schemes.




25/Sep/2002            Last change: 0.9.8o                      1






OpenSSL                          DH_generate_parameters(3openssl)



BBBBUUUUGGGGSSSS
     If ggggeeeennnneeeerrrraaaattttoooorrrr is not 2 or 5, ddddhhhh---->>>>gggg=ggggeeeennnneeeerrrraaaattttoooorrrr is not a usable
     generator.

SSSSEEEEEEEE AAAALLLLSSSSOOOO
     dh(3), ERR_get_error(3), rand(3), DH_free(3)

HHHHIIIISSSSTTTTOOOORRRRYYYY
     DH_check() is available in all versions of SSLeay and
     OpenSSL.  The ccccbbbb_aaaarrrrgggg argument to DH_generate_parameters()
     was added in SSLeay 0.9.0.

     In versions before OpenSSL 0.9.5,
     DH_CHECK_P_NOT_STRONG_PRIME is used instead of
     DH_CHECK_P_NOT_SAFE_PRIME.








































25/Sep/2002            Last change: 0.9.8o                      2