- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUE
- BUGS
- SEE ALSO
- COPYRIGHT

# 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:

     #if OPENSSL_API_COMPAT < 0x00908000L
     RSA *RSA_generate_key(int num, unsigned long e,
        void (*callback)(int, int, void *), void *cb_arg);
     #endif

# DESCRIPTION

RSA_generate_key_ex() generates a key pair and stores it in the RSA structure provided in rsa. The pseudo-random number generator must be seeded prior to calling RSA_generate_key_ex().

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() function described on the 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 RETURN VALUE

If key generation fails, RSA_generate_key() returns NULL.

The error codes can be obtained by 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.

# SEE ALSO

rand(3), BN_generate_prime(3)

# COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at https://www.openssl.org/source/license.html.