NAME    [Toc]    [Back]

       RSA_generate_key - Generate RSA key pair

SYNOPSIS    [Toc]    [Back]

       #include <openssl/rsa.h>

       RSA *RSA_generate_key(
               int num,
               unsigned long e,
               void ((*callback)(int,int,void *)),
               void *cb_arg );

DESCRIPTION    [Toc]    [Back]

       The  RSA_generate_key()  function generates a key pair and
       returns it in a newly allocated RSA structure. The pseudorandom
  number  generator  must be seeded prior to calling
       RSA_generate_key().

       The modulus size will be num bits, and the public exponent
       will  be e. Key sizes with num < 1024 should be considered
       insecure. The exponent is an odd number, typically  3,  17
       or 65537.

       A  callback function may be used to provide feedback about
       the progress of the key generation.  If  callback  is  not
       NULL,  it  will be called as follows: While a random prime
       number is generated, it is called as described in  BN_generate_prime(3).  When the n-th randomly generated prime is
       rejected as not  suitable  for  the  key,  callback(2,  n,
       cb_arg)  is  called.   When a random p has been found with
       p-1 relatively prime to e, it is called as callback(3,  0,
       cb_arg).

       The  process is then repeated for prime q with callback(3,
       1, cb_arg).

RESTRICTIONS    [Toc]    [Back]

       callback(2, x, cb_arg) is used with  two  different  meanings.


       The RSA_generate_key() function goes into an infinite loop
       for illegal input values.

RETURN VALUE    [Toc]    [Back]

       If key generation fails, RSA_generate_key() returns  NULL;
       the   error   codes   can   be   obtained   by  using  the
       ERR_get_error() function.

HISTORY    [Toc]    [Back]

       The cb_arg argument was added in SSLeay 0.9.0.

SEE ALSO    [Toc]    [Back]

       Functions: err(3),

       rand_ssl(3),

       rsa(3),

       RSA_free(3)



                                              RSA_generate_key(3)