Manual Pages for UNIX Operating System command usage for man RAND_set_rand_method

OpenSSL                            RAND_set_rand_method(3openssl)



NNNNAAAAMMMMEEEE
     RAND_set_rand_method, RAND_get_rand_method, RAND_SSLeay -
     select RAND method

SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
      #include 

      void RAND_set_rand_method(const RAND_METHOD *meth);

      const RAND_METHOD *RAND_get_rand_method(void);

      RAND_METHOD *RAND_SSLeay(void);


DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
     A RRRRAAAANNNNDDDD_MMMMEEEETTTTHHHHOOOODDDD specifies the functions that OpenSSL uses for
     random number generation. By modifying the method,
     alternative implementations such as hardware RNGs may be
     used. IMPORTANT: See the NOTES section for important
     information about how these RAND API functions are affected
     by the use of EEEENNNNGGGGIIIINNNNEEEE API calls.

     Initially, the default RAND_METHOD is the OpenSSL internal
     implementation, as returned by RAND_SSLeay().

     RAND_set_default_method() makes mmmmeeeetttthhhh the method for PRNG
     use. NNNNBBBB: This is true only whilst no ENGINE has been set as
     a default for RAND, so this function is no longer
     recommended.

     RAND_get_default_method() returns a pointer to the current
     RAND_METHOD.  However, the meaningfulness of this result is
     dependent on whether the ENGINE API is being used, so this
     function is no longer recommended.

TTTTHHHHEEEE RRRRAAAANNNNDDDD_MMMMEEEETTTTHHHHOOOODDDD SSSSTTTTRRRRUUUUCCCCTTTTUUUURRRREEEE
      typedef struct rand_meth_st
      {
             void (*seed)(const void *buf, int num);
             int (*bytes)(unsigned char *buf, int num);
             void (*cleanup)(void);
             void (*add)(const void *buf, int num, int entropy);
             int (*pseudorand)(unsigned char *buf, int num);
             int (*status)(void);
      } RAND_METHOD;

     The components point to the implementation of RAND_seed(),
     RAND_bytes(), RAND_cleanup(), RAND_add(), RAND_pseudo_rand()
     and RAND_status().  Each component may be NULL if the
     function is not implemented.





19/Nov/2007            Last change: 0.9.8o                      1






OpenSSL                            RAND_set_rand_method(3openssl)



RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEESSSS
     RAND_set_rand_method() returns no value.
     RAND_get_rand_method() and RAND_SSLeay() return pointers to
     the respective methods.

NNNNOOOOTTTTEEEESSSS
     As of version 0.9.7, RAND_METHOD implementations are grouped
     together with other algorithmic APIs (eg. RSA_METHOD,
     EVP_CIPHER, etc) in EEEENNNNGGGGIIIINNNNEEEE modules. If a default ENGINE is
     specified for RAND functionality using an ENGINE API
     function, that will override any RAND defaults set using the
     RAND API (ie.  RAND_set_rand_method()). For this reason, the
     ENGINE API is the recommended way to control default
     implementations for use in RAND and other cryptographic
     algorithms.

SSSSEEEEEEEE AAAALLLLSSSSOOOO
     rand(3), engine(3)

HHHHIIIISSSSTTTTOOOORRRRYYYY
     RAND_set_rand_method(), RAND_get_rand_method() and
     RAND_SSLeay() are available in all versions of OpenSSL.

     In the engine version of version 0.9.6,
     RAND_set_rand_method() was altered to take an ENGINE pointer
     as its argument. As of version 0.9.7, that has been reverted
     as the ENGINE API transparently overrides RAND defaults if
     used, otherwise RAND API functions work as before.
     RAND_set_rand_engine() was also introduced in version 0.9.7.


























19/Nov/2007            Last change: 0.9.8o                      2