RSA_check_key
Section: OpenSSL (3SSL)
Updated: 20160503
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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
p and
q are
in fact prime, and that
n = p*q.
It also checks that d*e = 1 mod (p1*q1),
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.
RETURN VALUE
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).
NOTES
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.
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 objectorientation 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.
SEE ALSO
rsa(3),
ERR_get_error(3)
HISTORY
RSA_check_key() appeared in OpenSSL 0.9.4.
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 NOTES

 BUGS

 SEE ALSO

 HISTORY
