Cryptography and SSL/TLS Toolkit



RSA_set0_key, RSA_set0_factors, RSA_set0_crt_params, RSA_get0_key, RSA_get0_factors, RSA_get0_crt_params, RSA_clear_flags, RSA_test_flags, RSA_set_flags, RSA_get0_engine - Routines for getting and setting data in an RSA object


 #include <openssl/rsa.h>

 int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d);
 int RSA_set0_factors(RSA *r, BIGNUM *p, BIGNUM *q);
 int RSA_set0_crt_params(RSA *r, BIGNUM *dmp1, BIGNUM *dmq1, BIGNUM *iqmp);
 void RSA_get0_key(const RSA *r,
                   const BIGNUM **n, const BIGNUM **e, const BIGNUM **d);
 void RSA_get0_factors(const RSA *r, const BIGNUM **p, const BIGNUM **q);
 void RSA_get0_crt_params(const RSA *r,
                          const BIGNUM **dmp1, const BIGNUM **dmq1,
                          const BIGNUM **iqmp);
 void RSA_clear_flags(RSA *r, int flags);
 int RSA_test_flags(const RSA *r, int flags);
 void RSA_set_flags(RSA *r, int flags);
 ENGINE *RSA_get0_engine(RSA *r);


An RSA object contains the components for the public and private key, n, e, d, p, q, dmp1, dmq1 and iqmp. n is the modulus common to both public and private key, e is the public exponent and d is the private exponent. p, q, dmp1, dmq1 and iqmp are the factors for the second representation of a private key (see PKCS#1 section 3 Key Types), where p and q are the first and second factor of n and dmp1, dmq1 and iqmp are the exponents and coefficient for CRT calculations.

The n, e and d parameters can be obtained by calling RSA_get0_key(). If they have not been set yet, then *n, *e and *d will be set to NULL. Otherwise, they are set to pointers to their respective values. These point directly to the internal representations of the values and therefore should not be freed by the caller.

The n, e and d parameter values can be set by calling RSA_set0_key() and passing the new values for n, e and d as parameters to the function. The values n and e must be non-NULL the first time this function is called on a given RSA object. The value d may be NULL. On subsequent calls any of these values may be NULL which means the corresponding RSA field is left untouched. Calling this function transfers the memory management of the values to the RSA object, and therefore the values that have been passed in should not be freed by the caller after this function has been called.

In a similar fashion, the p and q parameters can be obtained and set with RSA_get0_factors() and RSA_set0_factors(), and the dmp1, dmq1 and iqmp parameters can be obtained and set with RSA_get0_crt_params() and RSA_set0_crt_params().

For RSA_get0_key(), RSA_get0_factors(), and RSA_get0_crt_params(), NULL value BIGNUM ** output parameters are permitted. The functions ignore NULL parameters but return values for other, non-NULL, parameters.

RSA_set_flags() sets the flags in the flags parameter on the RSA object. Multiple flags can be passed in one go (bitwise ORed together). Any flags that are already set are left set. RSA_test_flags() tests to see whether the flags passed in the flags parameter are currently set in the RSA object. Multiple flags can be tested in one go. All flags that are currently set are returned, or zero if none of the flags are set. RSA_clear_flags() clears the specified flags within the RSA object.

RSA_get0_engine() returns a handle to the ENGINE that has been set for this RSA object, or NULL if no such ENGINE has been set.


Values retrieved with RSA_get0_key() are owned by the RSA object used in the call and may therefore not be passed to RSA_set0_key(). If needed, duplicate the received value using BN_dup() and pass the duplicate. The same applies to RSA_get0_factors() and RSA_set0_factors() as well as RSA_get0_crt_params() and RSA_set0_crt_params().


RSA_set0_key(), RSA_set0_factors and RSA_set0_crt_params() return 1 on success or 0 on failure.

RSA_test_flags() returns the current state of the flags in the RSA object.

RSA_get0_engine() returns the ENGINE set for the RSA object or NULL if no ENGINE has been set.


rsa(3), RSA_new(3), RSA_size(3)


The functions described here were added in OpenSSL 1.1.0.

Copyright 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