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