=pod =head1 NAME DSA_set_default_method, DSA_get_default_method, DSA_set_method, DSA_new_method, DSA_OpenSSL - select DSA method =head1 SYNOPSIS #include void DSA_set_default_method(DSA_METHOD *meth); DSA_METHOD *DSA_get_default_method(void); DSA_METHOD *DSA_set_method(DSA *dsa, DSA_METHOD *meth); DSA *DSA_new_method(DSA_METHOD *meth); DSA_METHOD *DSA_OpenSSL(void); =head1 DESCRIPTION A B specifies the functions that OpenSSL uses for DSA operations. By modifying the method, alternative implementations such as hardware accelerators may be used. Initially, the default is to use the OpenSSL internal implementation. DSA_OpenSSL() returns a pointer to that method. DSA_set_default_method() makes B the default method for all B structures created later. DSA_get_default_method() returns a pointer to the current default method. DSA_set_method() selects B for all operations using the structure B. DSA_new_method() allocates and initializes a B structure so that B will be used for the DSA operations. If B is B, the default method is used. =head1 THE DSA_METHOD STRUCTURE struct { /* name of the implementation */ const char *name; /* sign */ DSA_SIG *(*dsa_do_sign)(const unsigned char *dgst, int dlen, DSA *dsa); /* pre-compute k^-1 and r */ int (*dsa_sign_setup)(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp); /* verify */ int (*dsa_do_verify)(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, DSA *dsa); /* compute rr = a1^p1 * a2^p2 mod m (May be NULL for some implementations) */ int (*dsa_mod_exp)(DSA *dsa, BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2, BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont); /* compute r = a ^ p mod m (May be NULL for some implementations) */ int (*bn_mod_exp)(DSA *dsa, BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); /* called at DSA_new */ int (*init)(DSA *DSA); /* called at DSA_free */ int (*finish)(DSA *DSA); int flags; char *app_data; /* ?? */ } DSA_METHOD; =head1 RETURN VALUES DSA_OpenSSL() and DSA_get_default_method() return pointers to the respective Bs. DSA_set_default_method() returns no value. DSA_set_method() returns a pointer to the B previously associated with B. DSA_new_method() returns B and sets an error code that can be obtained by L if the allocation fails. Otherwise it returns a pointer to the newly allocated structure. =head1 SEE ALSO L, L =head1 HISTORY DSA_set_default_method(), DSA_get_default_method(), DSA_set_method(), DSA_new_method() and DSA_OpenSSL() were added in OpenSSL 0.9.4. =cut