1RSA_check_key(3)                    OpenSSL                   RSA_check_key(3)
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NAME

6       RSA_check_key - validate private RSA keys
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SYNOPSIS

9        #include <openssl/rsa.h>
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11        int RSA_check_key(RSA *rsa);
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DESCRIPTION

14       This function validates RSA keys. It checks that p and q are in fact
15       prime, and that n = p*q.
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17       It also checks that d*e = 1 mod (p-1*q-1), and that dmp1, dmq1 and iqmp
18       are set correctly or are NULL.
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20       As such, this function can not be used with any arbitrary RSA key
21       object, even if it is otherwise fit for regular RSA operation. See
22       NOTES for more information.
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RETURN VALUE

25       RSA_check_key() returns 1 if rsa is a valid RSA key, and 0 otherwise.
26       -1 is returned if an error occurs while checking the key.
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28       If the key is invalid or an error occurred, the reason code can be
29       obtained using ERR_get_error(3).
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NOTES

32       This function does not work on RSA public keys that have only the
33       modulus and public exponent elements populated. It performs integrity
34       checks on all the RSA key material, so the RSA key structure must
35       contain all the private key data too.
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37       Unlike most other RSA functions, this function does not work
38       transparently with any underlying ENGINE implementation because it uses
39       the key data in the RSA structure directly. An ENGINE implementation
40       can override the way key data is stored and handled, and can even
41       provide support for HSM keys - in which case the RSA structure may
42       contain no key data at all! If the ENGINE in question is only being
43       used for acceleration or analysis purposes, then in all likelihood the
44       RSA key data is complete and untouched, but this can't be assumed in
45       the general case.
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BUGS

48       A method of verifying the RSA key using opaque RSA API functions might
49       need to be considered. Right now RSA_check_key() simply uses the RSA
50       structure elements directly, bypassing the RSA_METHOD table altogether
51       (and completely violating encapsulation and object-orientation in the
52       process).  The best fix will probably be to introduce a "check_key()"
53       handler to the RSA_METHOD function table so that alternative
54       implementations can also provide their own verifiers.
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SEE ALSO

57       rsa(3), ERR_get_error(3)
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HISTORY

60       RSA_check_key() appeared in OpenSSL 0.9.4.
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641.0.2k                            2017-01-26                  RSA_check_key(3)
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