1=pod 2 3=head1 NAME 4 5DSA_meth_new, DSA_meth_free, DSA_meth_dup, DSA_meth_get0_name, 6DSA_meth_set1_name, DSA_meth_get_flags, DSA_meth_set_flags, 7DSA_meth_get0_app_data, DSA_meth_set0_app_data, DSA_meth_get_sign, 8DSA_meth_set_sign, DSA_meth_get_sign_setup, DSA_meth_set_sign_setup, 9DSA_meth_get_verify, DSA_meth_set_verify, DSA_meth_get_mod_exp, 10DSA_meth_set_mod_exp, DSA_meth_get_bn_mod_exp, DSA_meth_set_bn_mod_exp, 11DSA_meth_get_init, DSA_meth_set_init, DSA_meth_get_finish, DSA_meth_set_finish, 12DSA_meth_get_paramgen, DSA_meth_set_paramgen, DSA_meth_get_keygen, 13DSA_meth_set_keygen - Routines to build up DSA methods 14 15=head1 SYNOPSIS 16 17 #include <openssl/dsa.h> 18 19 DSA_METHOD *DSA_meth_new(const char *name, int flags); 20 21 void DSA_meth_free(DSA_METHOD *dsam); 22 23 DSA_METHOD *DSA_meth_dup(const DSA_METHOD *meth); 24 25 const char *DSA_meth_get0_name(const DSA_METHOD *dsam); 26 int DSA_meth_set1_name(DSA_METHOD *dsam, const char *name); 27 28 int DSA_meth_get_flags(const DSA_METHOD *dsam); 29 int DSA_meth_set_flags(DSA_METHOD *dsam, int flags); 30 31 void *DSA_meth_get0_app_data(const DSA_METHOD *dsam); 32 int DSA_meth_set0_app_data(DSA_METHOD *dsam, void *app_data); 33 34 DSA_SIG *(*DSA_meth_get_sign(const DSA_METHOD *dsam))(const unsigned char *, 35 int, DSA *); 36 int DSA_meth_set_sign(DSA_METHOD *dsam, DSA_SIG *(*sign)(const unsigned char *, 37 int, DSA *)); 38 39 int (*DSA_meth_get_sign_setup(const DSA_METHOD *dsam))(DSA *, BN_CTX *,$ 40 BIGNUM **, BIGNUM **); 41 int DSA_meth_set_sign_setup(DSA_METHOD *dsam, int (*sign_setup)(DSA *, BN_CTX *, 42 BIGNUM **, BIGNUM **)); 43 44 int (*DSA_meth_get_verify(const DSA_METHOD *dsam))(const unsigned char *, 45 int, DSA_SIG *, DSA *); 46 int DSA_meth_set_verify(DSA_METHOD *dsam, int (*verify)(const unsigned char *, 47 int, DSA_SIG *, DSA *)); 48 49 int (*DSA_meth_get_mod_exp(const DSA_METHOD *dsam))(DSA *dsa, BIGNUM *rr, BIGNUM *a1, 50 BIGNUM *p1, BIGNUM *a2, BIGNUM *p2, 51 BIGNUM *m, BN_CTX *ctx, 52 BN_MONT_CTX *in_mont); 53 int DSA_meth_set_mod_exp(DSA_METHOD *dsam, int (*mod_exp)(DSA *dsa, BIGNUM *rr, 54 BIGNUM *a1, BIGNUM *p1, 55 BIGNUM *a2, BIGNUM *p2, 56 BIGNUM *m, BN_CTX *ctx, 57 BN_MONT_CTX *mont)); 58 59 int (*DSA_meth_get_bn_mod_exp(const DSA_METHOD *dsam))(DSA *dsa, BIGNUM *r, BIGNUM *a, 60 const BIGNUM *p, const BIGNUM *m, 61 BN_CTX *ctx, BN_MONT_CTX *mont); 62 int DSA_meth_set_bn_mod_exp(DSA_METHOD *dsam, int (*bn_mod_exp)(DSA *dsa, 63 BIGNUM *r, 64 BIGNUM *a, 65 const BIGNUM *p, 66 const BIGNUM *m, 67 BN_CTX *ctx, 68 BN_MONT_CTX *mont)); 69 70 int (*DSA_meth_get_init(const DSA_METHOD *dsam))(DSA *); 71 int DSA_meth_set_init(DSA_METHOD *dsam, int (*init)(DSA *)); 72 73 int (*DSA_meth_get_finish(const DSA_METHOD *dsam))(DSA *); 74 int DSA_meth_set_finish(DSA_METHOD *dsam, int (*finish)(DSA *)); 75 76 int (*DSA_meth_get_paramgen(const DSA_METHOD *dsam))(DSA *, int, 77 const unsigned char *, 78 int, int *, unsigned long *, 79 BN_GENCB *); 80 int DSA_meth_set_paramgen(DSA_METHOD *dsam, 81 int (*paramgen)(DSA *, int, const unsigned char *, 82 int, int *, unsigned long *, BN_GENCB *)); 83 84 int (*DSA_meth_get_keygen(const DSA_METHOD *dsam))(DSA *); 85 int DSA_meth_set_keygen(DSA_METHOD *dsam, int (*keygen)(DSA *)); 86 87=head1 DESCRIPTION 88 89The B<DSA_METHOD> type is a structure used for the provision of custom DSA 90implementations. It provides a set of functions used by OpenSSL for the 91implementation of the various DSA capabilities. See the L<dsa> page for more 92information. 93 94DSA_meth_new() creates a new B<DSA_METHOD> structure. It should be given a 95unique B<name> and a set of B<flags>. The B<name> should be a NULL terminated 96string, which will be duplicated and stored in the B<DSA_METHOD> object. It is 97the callers responsibility to free the original string. The flags will be used 98during the construction of a new B<DSA> object based on this B<DSA_METHOD>. Any 99new B<DSA> object will have those flags set by default. 100 101DSA_meth_dup() creates a duplicate copy of the B<DSA_METHOD> object passed as a 102parameter. This might be useful for creating a new B<DSA_METHOD> based on an 103existing one, but with some differences. 104 105DSA_meth_free() destroys a B<DSA_METHOD> structure and frees up any memory 106associated with it. 107 108DSA_meth_get0_name() will return a pointer to the name of this DSA_METHOD. This 109is a pointer to the internal name string and so should not be freed by the 110caller. DSA_meth_set1_name() sets the name of the DSA_METHOD to B<name>. The 111string is duplicated and the copy is stored in the DSA_METHOD structure, so the 112caller remains responsible for freeing the memory associated with the name. 113 114DSA_meth_get_flags() returns the current value of the flags associated with this 115DSA_METHOD. DSA_meth_set_flags() provides the ability to set these flags. 116 117The functions DSA_meth_get0_app_data() and DSA_meth_set0_app_data() provide the 118ability to associate implementation specific data with the DSA_METHOD. It is 119the application's responsibility to free this data before the DSA_METHOD is 120freed via a call to DSA_meth_free(). 121 122DSA_meth_get_sign() and DSA_meth_set_sign() get and set the function used for 123creating a DSA signature respectively. This function will be 124called in response to the application calling DSA_do_sign() (or DSA_sign()). The 125parameters for the function have the same meaning as for DSA_do_sign(). 126 127DSA_meth_get_sign_setup() and DSA_meth_set_sign_setup() get and set the function 128used for precalculating the DSA signature values B<k^-1> and B<r>. This function 129will be called in response to the application calling DSA_sign_setup(). The 130parameters for the function have the same meaning as for DSA_sign_setup(). 131 132DSA_meth_get_verify() and DSA_meth_set_verify() get and set the function used 133for verifying a DSA signature respectively. This function will be called in 134response to the application calling DSA_do_verify() (or DSA_verify()). The 135parameters for the function have the same meaning as for DSA_do_verify(). 136 137DSA_meth_get_mod_exp() and DSA_meth_set_mod_exp() get and set the function used 138for computing the following value: 139 140 rr = a1^p1 * a2^p2 mod m 141 142This function will be called by the default OpenSSL method during verification 143of a DSA signature. The result is stored in the B<rr> parameter. This function 144may be NULL. 145 146DSA_meth_get_bn_mod_exp() and DSA_meth_set_bn_mod_exp() get and set the function 147used for computing the following value: 148 149 r = a ^ p mod m 150 151This function will be called by the default OpenSSL function for 152DSA_sign_setup(). The result is stored in the B<r> parameter. This function 153may be NULL. 154 155DSA_meth_get_init() and DSA_meth_set_init() get and set the function used 156for creating a new DSA instance respectively. This function will be 157called in response to the application calling DSA_new() (if the current default 158DSA_METHOD is this one) or DSA_new_method(). The DSA_new() and DSA_new_method() 159functions will allocate the memory for the new DSA object, and a pointer to this 160newly allocated structure will be passed as a parameter to the function. This 161function may be NULL. 162 163DSA_meth_get_finish() and DSA_meth_set_finish() get and set the function used 164for destroying an instance of a DSA object respectively. This function will be 165called in response to the application calling DSA_free(). A pointer to the DSA 166to be destroyed is passed as a parameter. The destroy function should be used 167for DSA implementation specific clean up. The memory for the DSA itself should 168not be freed by this function. This function may be NULL. 169 170DSA_meth_get_paramgen() and DSA_meth_set_paramgen() get and set the function 171used for generating DSA parameters respectively. This function will be called in 172response to the application calling DSA_generate_parameters_ex() (or 173DSA_generate_parameters()). The parameters for the function have the same 174meaning as for DSA_generate_parameters_ex(). 175 176DSA_meth_get_keygen() and DSA_meth_set_keygen() get and set the function 177used for generating a new DSA key pair respectively. This function will be 178called in response to the application calling DSA_generate_key(). The parameter 179for the function has the same meaning as for DSA_generate_key(). 180 181=head1 RETURN VALUES 182 183DSA_meth_new() and DSA_meth_dup() return the newly allocated DSA_METHOD object 184or NULL on failure. 185 186DSA_meth_get0_name() and DSA_meth_get_flags() return the name and flags 187associated with the DSA_METHOD respectively. 188 189All other DSA_meth_get_*() functions return the appropriate function pointer 190that has been set in the DSA_METHOD, or NULL if no such pointer has yet been 191set. 192 193DSA_meth_set1_name() and all DSA_meth_set_*() functions return 1 on success or 1940 on failure. 195 196=head1 SEE ALSO 197 198L<DSA_new(3)>, L<DSA_new(3)>, L<DSA_generate_parameters(3)>, L<DSA_generate_key(3)>, 199L<DSA_dup_DH(3)>, L<DSA_do_sign(3)>, L<DSA_set_method(3)>, L<DSA_SIG_new(3)>, 200L<DSA_sign(3)>, L<DSA_size(3)>, L<DSA_get0_pqg(3)> 201 202=head1 HISTORY 203 204The functions described here were added in OpenSSL 1.1.0. 205 206=head1 COPYRIGHT 207 208Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved. 209 210Licensed under the OpenSSL license (the "License"). You may not use 211this file except in compliance with the License. You can obtain a copy 212in the file LICENSE in the source distribution or at 213L<https://www.openssl.org/source/license.html>. 214 215=cut 216