NAME
RSA_generate_key_ex,
RSA_generate_key —
generate RSA key pair
SYNOPSIS
#include
<openssl/rsa.h>
int
RSA_generate_key_ex(RSA *rsa,
int bits, BIGNUM *e,
BN_GENCB *cb);
Deprecated:
RSA *
RSA_generate_key(int num,
unsigned long e, void (*callback)(int,
int, void *), void *cb_arg);
DESCRIPTION
RSA_generate_key_ex()
generates a key pair and stores it in rsa.
The modulus size will be of length 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 cb is not
NULL, it will be called as follows using the
BN_GENCB_call(3) function:
- 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,
BN_GENCB_call(cb, 2, n) is called. - When a random p has been found with p-1 relatively prime to
e, it is called as
BN_GENCB_call(cb, 3, 0).
The process is then repeated for prime q with
BN_GENCB_call(cb,
3, 1).
RSA_generate_key()
is deprecated. New applications should use
RSA_generate_key_ex() instead.
RSA_generate_key() works in the same way as
RSA_generate_key_ex() except it uses "old
style" call backs. See
BN_generate_prime(3) for further details.
RETURN VALUES
RSA_generate_key_ex() returns 1 on success
or 0 on error. RSA_generate_key() returns the key on
success or NULL on error.
The error codes can be obtained by ERR_get_error(3).
SEE ALSO
BN_generate_prime(3), RSA_get0_key(3), RSA_meth_set_keygen(3), RSA_new(3)
HISTORY
RSA_generate_key() appeared in SSLeay 0.4
or earlier and had its cb_arg argument added in SSLeay
0.9.0. It has been available since OpenBSD 2.4.
RSA_generate_key_ex() first appeared in
OpenSSL 0.9.8 and has been available since OpenBSD
4.5.
BUGS
BN_GENCB_call(cb,
2, x) is used with two different
meanings.
RSA_generate_key() goes into an infinite
loop for illegal input values.