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RSA_check_key(3) OpenSSL RSA_check_key(3)
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 =
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 information.
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
This function does not work on RSA public keys that have only the modulus and public expo-
nent 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 under-
lying 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 consid-
ered. Right now RSA_check_key() simply uses the RSA structure elements directly, bypassing
the RSA_METHOD table altogether (and completely violating encapsulation and object-orien-
tation in the process). The best fix will probably be to introduce a "check_key()" han-
dler 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.
0.9.7d 2003-11-20 RSA_check_key(3)
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