NAME
RSA_check_key —
validate private RSA keys
SYNOPSIS
#include
<openssl/rsa.h>
int
RSA_check_key(RSA *rsa);
DESCRIPTION
This function validates RSA keys. It checks that rsa->p and rsa->q are in fact prime, and that rsa->n satisfies n = p*q.
It also checks that rsa->d and
rsa->e satisfy d*e = 1 mod ((p-1)*(q-1)), and that
rsa->dmp1, rsa->dmq1, and
resa->iqmp are set correctly or are
NULL.
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. Therefore, it cannot be used with any arbitrary RSA key object, even if it is otherwise fit for regular RSA operation.
RETURN VALUES
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).
SEE ALSO
HISTORY
RSA_check_key() first appeared in OpenSSL
0.9.4 and has been available since OpenBSD 2.6.
BUGS
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.