Страницы справочника OS X

Эта страница руководства является частью версии 5.0 Инструментов XCode

Читать страницы руководства

RSA_set_method(3)                                  OpenSSL                                 RSA_set_method(3)



NAME
       RSA_set_default_method, RSA_get_default_method, RSA_set_method, RSA_get_method, RSA_PKCS1_SSLeay,
       RSA_null_method, RSA_flags, RSA_new_method - select RSA method

SYNOPSIS
        #include <openssl/rsa.h>

        void RSA_set_default_method(const RSA_METHOD *meth);

        RSA_METHOD *RSA_get_default_method(void);

        int RSA_set_method(RSA *rsa, const RSA_METHOD *meth);

        RSA_METHOD *RSA_get_method(const RSA *rsa);

        RSA_METHOD *RSA_PKCS1_SSLeay(void);

        RSA_METHOD *RSA_null_method(void);

        int RSA_flags(const RSA *rsa);

        RSA *RSA_new_method(RSA_METHOD *method);

DESCRIPTION
       An RSA_METHOD specifies the functions that OpenSSL uses for RSA operations. By modifying the method,
       alternative implementations such as hardware accelerators may be used. IMPORTANT: See the NOTES
       section for important information about how these RSA API functions are affected by the use of ENGINE
       API calls.

       Initially, the default RSA_METHOD is the OpenSSL internal implementation, as returned by
       RSA_PKCS1_SSLeay().

       RSA_set_default_method() makes meth the default method for all RSA structures created later. NB: This
       is true only whilst no ENGINE has been set as a default for RSA, so this function is no longer
       recommended.

       RSA_get_default_method() returns a pointer to the current default RSA_METHOD. However, the
       meaningfulness of this result is dependent on whether the ENGINE API is being used, so this function
       is no longer recommended.

       RSA_set_method() selects meth to perform all operations using the key rsa. This will replace the
       RSA_METHOD used by the RSA key and if the previous method was supplied by an ENGINE, the handle to
       that ENGINE will be released during the change. It is possible to have RSA keys that only work with
       certain RSA_METHOD implementations (eg. from an ENGINE module that supports embedded hardware-protected hardwareprotected
       protected keys), and in such cases attempting to change the RSA_METHOD for the key can have
       unexpected results.

       RSA_get_method() returns a pointer to the RSA_METHOD being used by rsa.  This method may or may not
       be supplied by an ENGINE implementation, but if it is, the return value can only be guaranteed to be
       valid as long as the RSA key itself is valid and does not have its implementation changed by
       RSA_set_method().

       RSA_flags() returns the flags that are set for rsa's current RSA_METHOD. See the BUGS section.

       RSA_new_method() allocates and initializes an RSA structure so that engine will be used for the RSA
       operations. If engine is NULL, the default ENGINE for RSA operations is used, and if no default
       ENGINE is set, the RSA_METHOD controlled by RSA_set_default_method() is used.

       RSA_flags() returns the flags that are set for rsa's current method.

       RSA_new_method() allocates and initializes an RSA structure so that method will be used for the RSA
       operations. If method is NULL, the default method is used.

THE RSA_METHOD STRUCTURE
        typedef struct rsa_meth_st
        {
            /* name of the implementation */
               const char *name;

            /* encrypt */
               int (*rsa_pub_enc)(int flen, unsigned char *from,
                 unsigned char *to, RSA *rsa, int padding);

            /* verify arbitrary data */
               int (*rsa_pub_dec)(int flen, unsigned char *from,
                 unsigned char *to, RSA *rsa, int padding);

            /* sign arbitrary data */
               int (*rsa_priv_enc)(int flen, unsigned char *from,
                 unsigned char *to, RSA *rsa, int padding);

            /* decrypt */
               int (*rsa_priv_dec)(int flen, unsigned char *from,
                 unsigned char *to, RSA *rsa, int padding);

            /* compute r0 = r0 ^ I mod rsa->n (May be NULL for some
                                               implementations) */
               int (*rsa_mod_exp)(BIGNUM *r0, BIGNUM *I, RSA *rsa);

            /* compute r = a ^ p mod m (May be NULL for some implementations) */
               int (*bn_mod_exp)(BIGNUM *r, BIGNUM *a, const BIGNUM *p,
                 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);

            /* called at RSA_new */
               int (*init)(RSA *rsa);

            /* called at RSA_free */
               int (*finish)(RSA *rsa);

            /* RSA_FLAG_EXT_PKEY        - rsa_mod_exp is called for private key
             *                            operations, even if p,q,dmp1,dmq1,iqmp
             *                            are NULL
             * RSA_FLAG_SIGN_VER        - enable rsa_sign and rsa_verify
             * RSA_METHOD_FLAG_NO_CHECK - don't check pub/private match
             */
               int flags;

               char *app_data; /* ?? */

            /* sign. For backward compatibility, this is used only
             * if (flags & RSA_FLAG_SIGN_VER)
             */
               int (*rsa_sign)(int type, unsigned char *m, unsigned int m_len,
                  unsigned char *sigret, unsigned int *siglen, RSA *rsa);

            /* verify. For backward compatibility, this is used only
             * if (flags & RSA_FLAG_SIGN_VER)
             */
               int (*rsa_verify)(int type, unsigned char *m, unsigned int m_len,
                  unsigned char *sigbuf, unsigned int siglen, RSA *rsa);

        } RSA_METHOD;

RETURN VALUES
       RSA_PKCS1_SSLeay(), RSA_PKCS1_null_method(), RSA_get_default_method() and RSA_get_method() return
       pointers to the respective RSA_METHODs.

       RSA_set_default_method() returns no value.

       RSA_set_method() returns a pointer to the old RSA_METHOD implementation that was replaced. However,
       this return value should probably be ignored because if it was supplied by an ENGINE, the pointer
       could be invalidated at any time if the ENGINE is unloaded (in fact it could be unloaded as a result
       of the RSA_set_method() function releasing its handle to the ENGINE). For this reason, the return
       type may be replaced with a void declaration in a future release.

       RSA_new_method() returns NULL and sets an error code that can be obtained by ERR_get_error(3) if the
       allocation fails. Otherwise it returns a pointer to the newly allocated structure.

NOTES
       As of version 0.9.7, RSA_METHOD implementations are grouped together with other algorithmic APIs (eg.
       DSA_METHOD, EVP_CIPHER, etc) into ENGINE modules. If a default ENGINE is specified for RSA
       functionality using an ENGINE API function, that will override any RSA defaults set using the RSA API
       (ie.  RSA_set_default_method()). For this reason, the ENGINE API is the recommended way to control
       default implementations for use in RSA and other cryptographic algorithms.

BUGS
       The behaviour of RSA_flags() is a mis-feature that is left as-is for now to avoid creating
       compatibility problems. RSA functionality, such as the encryption functions, are controlled by the
       flags value in the RSA key itself, not by the flags value in the RSA_METHOD attached to the RSA key
       (which is what this function returns). If the flags element of an RSA key is changed, the changes
       will be honoured by RSA functionality but will not be reflected in the return value of the
       RSA_flags() function - in effect RSA_flags() behaves more like an RSA_default_flags() function (which
       does not currently exist).

SEE ALSO
       rsa(3), RSA_new(3)

HISTORY
       RSA_new_method() and RSA_set_default_method() appeared in SSLeay 0.8.  RSA_get_default_method(),
       RSA_set_method() and RSA_get_method() as well as the rsa_sign and rsa_verify components of RSA_METHOD
       were added in OpenSSL 0.9.4.

       RSA_set_default_openssl_method() and RSA_get_default_openssl_method() replaced
       RSA_set_default_method() and RSA_get_default_method() respectively, and RSA_set_method() and
       RSA_new_method() were altered to use ENGINEs rather than RSA_METHODs during development of the engine
       version of OpenSSL 0.9.6. For 0.9.7, the handling of defaults in the ENGINE API was restructured so
       that this change was reversed, and behaviour of the other functions resembled more closely the
       previous behaviour. The behaviour of defaults in the ENGINE API now transparently overrides the
       behaviour of defaults in the RSA API without requiring changing these function prototypes.



50                                               2013-03-05                                RSA_set_method(3)