Man page of RSA_check_key
Section: OpenSSL (3SSL)
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RSA_check_key - validate private RSA keys
int RSA_check_key(RSA *rsa);
This function validates RSA keys. It checks that p and q are
in fact prime, and that n = p*q.
It also checks that d*e = 1 mod (p-1*q-1),
and that dmp1, dmq1 and iqmp are set correctly or are NULL.
As such, this function can not be used with any arbitrary RSA key object,
even if it is otherwise fit for regular RSA operation. See NOTES for more
RSA_check_key() returns 1 if rsa is a valid RSA key, and 0 otherwise.
-1 is returned 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).
This function does not work on RSA public keys that have only the modulus
and public exponent elements populated. It performs integrity checks on all
the RSA key material, so the RSA key structure must contain all the private
key data too.
Unlike most other RSA functions, this function does not work
transparently with any underlying ENGINE implementation because it uses the
key data in the RSA structure directly. An ENGINE implementation can
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 key data
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 structure
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
RSA_METHOD function table so that alternative implementations can also
provide their own verifiers.
RSA_check_key() appeared in OpenSSL 0.9.4.
- RETURN VALUE
- SEE ALSO
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Time: 04:14:18 GMT, September 24, 2010