1=pod 2 3=head1 NAME 4 5DH_meth_new, DH_meth_free, DH_meth_dup, DH_meth_get0_name, DH_meth_set1_name, 6DH_meth_get_flags, DH_meth_set_flags, DH_meth_get0_app_data, 7DH_meth_set0_app_data, DH_meth_get_generate_key, DH_meth_set_generate_key, 8DH_meth_get_compute_key, DH_meth_set_compute_key, DH_meth_get_bn_mod_exp, 9DH_meth_set_bn_mod_exp, DH_meth_get_init, DH_meth_set_init, DH_meth_get_finish, 10DH_meth_set_finish, DH_meth_get_generate_params, 11DH_meth_set_generate_params - Routines to build up DH methods 12 13=head1 SYNOPSIS 14 15 #include <openssl/dh.h> 16 17The following functions have been deprecated since OpenSSL 3.0, and can be 18hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 19see L<openssl_user_macros(7)>: 20 21 DH_METHOD *DH_meth_new(const char *name, int flags); 22 23 void DH_meth_free(DH_METHOD *dhm); 24 25 DH_METHOD *DH_meth_dup(const DH_METHOD *dhm); 26 27 const char *DH_meth_get0_name(const DH_METHOD *dhm); 28 int DH_meth_set1_name(DH_METHOD *dhm, const char *name); 29 30 int DH_meth_get_flags(const DH_METHOD *dhm); 31 int DH_meth_set_flags(DH_METHOD *dhm, int flags); 32 33 void *DH_meth_get0_app_data(const DH_METHOD *dhm); 34 int DH_meth_set0_app_data(DH_METHOD *dhm, void *app_data); 35 36 int (*DH_meth_get_generate_key(const DH_METHOD *dhm))(DH *); 37 int DH_meth_set_generate_key(DH_METHOD *dhm, int (*generate_key)(DH *)); 38 39 int (*DH_meth_get_compute_key(const DH_METHOD *dhm)) 40 (unsigned char *key, const BIGNUM *pub_key, DH *dh); 41 int DH_meth_set_compute_key(DH_METHOD *dhm, 42 int (*compute_key)(unsigned char *key, const BIGNUM *pub_key, DH *dh)); 43 44 int (*DH_meth_get_bn_mod_exp(const DH_METHOD *dhm)) 45 (const DH *dh, BIGNUM *r, const BIGNUM *a, const BIGNUM *p, 46 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); 47 int DH_meth_set_bn_mod_exp(DH_METHOD *dhm, 48 int (*bn_mod_exp)(const DH *dh, BIGNUM *r, const BIGNUM *a, 49 const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, 50 BN_MONT_CTX *m_ctx)); 51 52 int (*DH_meth_get_init(const DH_METHOD *dhm))(DH *); 53 int DH_meth_set_init(DH_METHOD *dhm, int (*init)(DH *)); 54 55 int (*DH_meth_get_finish(const DH_METHOD *dhm))(DH *); 56 int DH_meth_set_finish(DH_METHOD *dhm, int (*finish)(DH *)); 57 58 int (*DH_meth_get_generate_params(const DH_METHOD *dhm)) 59 (DH *, int, int, BN_GENCB *); 60 int DH_meth_set_generate_params(DH_METHOD *dhm, 61 int (*generate_params)(DH *, int, int, BN_GENCB *)); 62 63=head1 DESCRIPTION 64 65All of the functions described on this page are deprecated. 66Applications should instead use the provider APIs. 67 68The B<DH_METHOD> type is a structure used for the provision of custom DH 69implementations. It provides a set of functions used by OpenSSL for the 70implementation of the various DH capabilities. 71 72DH_meth_new() creates a new B<DH_METHOD> structure. It should be given a 73unique B<name> and a set of B<flags>. The B<name> should be a NULL terminated 74string, which will be duplicated and stored in the B<DH_METHOD> object. It is 75the callers responsibility to free the original string. The flags will be used 76during the construction of a new B<DH> object based on this B<DH_METHOD>. Any 77new B<DH> object will have those flags set by default. 78 79DH_meth_dup() creates a duplicate copy of the B<DH_METHOD> object passed as a 80parameter. This might be useful for creating a new B<DH_METHOD> based on an 81existing one, but with some differences. 82 83DH_meth_free() destroys a B<DH_METHOD> structure and frees up any memory 84associated with it. 85 86DH_meth_get0_name() will return a pointer to the name of this DH_METHOD. This 87is a pointer to the internal name string and so should not be freed by the 88caller. DH_meth_set1_name() sets the name of the DH_METHOD to B<name>. The 89string is duplicated and the copy is stored in the DH_METHOD structure, so the 90caller remains responsible for freeing the memory associated with the name. 91 92DH_meth_get_flags() returns the current value of the flags associated with this 93DH_METHOD. DH_meth_set_flags() provides the ability to set these flags. 94 95The functions DH_meth_get0_app_data() and DH_meth_set0_app_data() provide the 96ability to associate implementation specific data with the DH_METHOD. It is 97the application's responsibility to free this data before the DH_METHOD is 98freed via a call to DH_meth_free(). 99 100DH_meth_get_generate_key() and DH_meth_set_generate_key() get and set the 101function used for generating a new DH key pair respectively. This function will 102be called in response to the application calling DH_generate_key(). The 103parameter for the function has the same meaning as for DH_generate_key(). 104 105DH_meth_get_compute_key() and DH_meth_set_compute_key() get and set the 106function used for computing a new DH shared secret respectively. This function 107will be called in response to the application calling DH_compute_key(). The 108parameters for the function have the same meaning as for DH_compute_key(). 109 110DH_meth_get_bn_mod_exp() and DH_meth_set_bn_mod_exp() get and set the function 111used for computing the following value: 112 113 r = a ^ p mod m 114 115This function will be called by the default OpenSSL function for 116DH_generate_key(). The result is stored in the B<r> parameter. This function 117may be NULL unless using the default generate key function, in which case it 118must be present. 119 120DH_meth_get_init() and DH_meth_set_init() get and set the function used 121for creating a new DH instance respectively. This function will be 122called in response to the application calling DH_new() (if the current default 123DH_METHOD is this one) or DH_new_method(). The DH_new() and DH_new_method() 124functions will allocate the memory for the new DH object, and a pointer to this 125newly allocated structure will be passed as a parameter to the function. This 126function may be NULL. 127 128DH_meth_get_finish() and DH_meth_set_finish() get and set the function used 129for destroying an instance of a DH object respectively. This function will be 130called in response to the application calling DH_free(). A pointer to the DH 131to be destroyed is passed as a parameter. The destroy function should be used 132for DH implementation specific clean up. The memory for the DH itself should 133not be freed by this function. This function may be NULL. 134 135DH_meth_get_generate_params() and DH_meth_set_generate_params() get and set the 136function used for generating DH parameters respectively. This function will be 137called in response to the application calling DH_generate_parameters_ex() (or 138DH_generate_parameters()). The parameters for the function have the same 139meaning as for DH_generate_parameters_ex(). This function may be NULL. 140 141=head1 RETURN VALUES 142 143DH_meth_new() and DH_meth_dup() return the newly allocated DH_METHOD object 144or NULL on failure. 145 146DH_meth_get0_name() and DH_meth_get_flags() return the name and flags 147associated with the DH_METHOD respectively. 148 149All other DH_meth_get_*() functions return the appropriate function pointer 150that has been set in the DH_METHOD, or NULL if no such pointer has yet been 151set. 152 153DH_meth_set1_name() and all DH_meth_set_*() functions return 1 on success or 1540 on failure. 155 156=head1 SEE ALSO 157 158L<DH_new(3)>, L<DH_new(3)>, L<DH_generate_parameters(3)>, L<DH_generate_key(3)>, 159L<DH_set_method(3)>, L<DH_size(3)>, L<DH_get0_pqg(3)> 160 161=head1 HISTORY 162 163All of these functions were deprecated in OpenSSL 3.0. 164 165The functions described here were added in OpenSSL 1.1.0. 166 167=head1 COPYRIGHT 168 169Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved. 170 171Licensed under the Apache License 2.0 (the "License"). You may not use 172this file except in compliance with the License. You can obtain a copy 173in the file LICENSE in the source distribution or at 174L<https://www.openssl.org/source/license.html>. 175 176=cut 177