

 
Manual Reference Pages  RSA_GENERATE_KEY (3)
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NAME
RSA_generate_key  generate RSA key pair
CONTENTS
SYNOPSIS
#include <openssl/rsa.h>
RSA *RSA_generate_key(int num, unsigned long e,
void (*callback)(int,int,void *), void *cb_arg);
DESCRIPTION
RSA_generate_key() 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:

o

While a random prime number is generated, it is called as
described in BN_generate_prime(3).

o

When the nth randomly generated prime is rejected as not
suitable for the key, callback(2, n, cb_arg) is called.

o

When a random p has been found with p1 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).
RETURN VALUE
If key generation fails, RSA_generate_key() returns NULL; the
error codes can be obtained by ERR_get_error(3).
BUGS
callback(2, x, cb_arg) is used with two different meanings.
RSA_generate_key() goes into an infinite loop for illegal input values.
SEE ALSO
ERR_get_error(3), rand(3), rsa(3),
RSA_free(3)
HISTORY
The cb_arg argument was added in SSLeay 0.9.0.
1.0.1s  RSA_GENERATE_KEY (3)  20160301 
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