RSA_generate_key - generate RSA key pair
RSA *RSA_generate_key(int num, unsigned long e,
void (*callback)(int,int,void *), void *cb_arg);
generates a key pair and returns it in a newly
structure. The pseudo-random number generator must be
seeded prior to calling RSA_generate_key()
The modulus size will be num
bits, and the public exponent will be
. 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
- 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)
If key generation fails, RSA_generate_key()
error codes can be obtained by ERR_get_error(3)
callback(2, x, cb_arg)
is used with two different meanings.
goes into an infinite loop for illegal input values.
argument was added in SSLeay 0.9.0.