Section: OpenSSL (3)
RSA_check_key_ex, RSA_check_key - validate private RSA keys
int RSA_check_key_ex(RSA *rsa, BN_GENCB *cb);
int RSA_check_key(RSA *rsa);
function validates RSA
It checks that p
in fact prime, and that n = p*q
It does not work on RSA public keys that have only the modulus
and public exponent elements populated.
It also checks that d*e = 1 mod (p-1*q-1),
and that dmp1, dmq1 and iqmp are set correctly or are NULL.
It performs integrity checks on all
the RSA key material, so the RSA key structure must contain all the private
key data too.
Therefore, it cannot be used with any arbitrary RSA key object,
even if it is otherwise fit for regular RSA operation.
The cb parameter is a callback that will be invoked in the same
manner as BN_is_prime_ex(3).
RSA_check_key() is equivalent to RSA_check_key_ex() with a NULL cb.
return 1 if rsa
is a valid RSA
key, and 0 otherwise.
They return -1 if an error occurs while checking the key.
If the key is invalid or an error occurred, the reason code can be
obtained using ERR_get_error(3).
Unlike most other RSA
functions, this function does not
transparently with any underlying ENGINE
implementation because it uses the
key data in the RSA
structure directly. An ENGINE
override the way key data is stored and handled, and can even provide
support for HSM
keys - in which case the RSA
structure may contain no
key data at all! If the ENGINE
in question is only being used for
acceleration or analysis purposes, then in all likelihood the RSA
is complete and untouched, but this can't be assumed in the general case.
A method of verifying the RSA
key using opaque RSA API
functions might need
to be considered. Right now RSA_check_key()
simply uses the RSA
elements directly, bypassing the RSA_METHOD
table altogether (and
completely violating encapsulation and object-orientation in the process).
The best fix will probably be to introduce a ``check_key()
'' handler to the
function table so that alternative implementations can also
provide their own verifiers.
appeared after OpenSSL 1.0.2.
Copyright 2000-2018 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