DH_meth_new.pod 7.1 KB

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  1. =pod
  2. =head1 NAME
  3. DH_meth_new, DH_meth_free, DH_meth_dup, DH_meth_get0_name, DH_meth_set1_name,
  4. DH_meth_get_flags, DH_meth_set_flags, DH_meth_get0_app_data,
  5. DH_meth_set0_app_data, DH_meth_get_generate_key, DH_meth_set_generate_key,
  6. DH_meth_get_compute_key, DH_meth_set_compute_key, DH_meth_get_bn_mod_exp,
  7. DH_meth_set_bn_mod_exp, DH_meth_get_init, DH_meth_set_init, DH_meth_get_finish,
  8. DH_meth_set_finish, DH_meth_get_generate_params,
  9. DH_meth_set_generate_params - Routines to build up DH methods
  10. =head1 SYNOPSIS
  11. #include <openssl/dh.h>
  12. DH_METHOD *DH_meth_new(const char *name, int flags);
  13. void DH_meth_free(DH_METHOD *dhm);
  14. DH_METHOD *DH_meth_dup(const DH_METHOD *dhm);
  15. const char *DH_meth_get0_name(const DH_METHOD *dhm);
  16. int DH_meth_set1_name(DH_METHOD *dhm, const char *name);
  17. int DH_meth_get_flags(const DH_METHOD *dhm);
  18. int DH_meth_set_flags(DH_METHOD *dhm, int flags);
  19. void *DH_meth_get0_app_data(const DH_METHOD *dhm);
  20. int DH_meth_set0_app_data(DH_METHOD *dhm, void *app_data);
  21. int (*DH_meth_get_generate_key(const DH_METHOD *dhm))(DH *);
  22. int DH_meth_set_generate_key(DH_METHOD *dhm, int (*generate_key)(DH *));
  23. int (*DH_meth_get_compute_key(const DH_METHOD *dhm))
  24. (unsigned char *key, const BIGNUM *pub_key, DH *dh);
  25. int DH_meth_set_compute_key(DH_METHOD *dhm,
  26. int (*compute_key)(unsigned char *key, const BIGNUM *pub_key, DH *dh));
  27. int (*DH_meth_get_bn_mod_exp(const DH_METHOD *dhm))
  28. (const DH *dh, BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
  29. const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
  30. int DH_meth_set_bn_mod_exp(DH_METHOD *dhm,
  31. int (*bn_mod_exp)(const DH *dh, BIGNUM *r, const BIGNUM *a,
  32. const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
  33. BN_MONT_CTX *m_ctx));
  34. int (*DH_meth_get_init(const DH_METHOD *dhm))(DH *);
  35. int DH_meth_set_init(DH_METHOD *dhm, int (*init)(DH *));
  36. int (*DH_meth_get_finish(const DH_METHOD *dhm))(DH *);
  37. int DH_meth_set_finish(DH_METHOD *dhm, int (*finish)(DH *));
  38. int (*DH_meth_get_generate_params(const DH_METHOD *dhm))
  39. (DH *, int, int, BN_GENCB *);
  40. int DH_meth_set_generate_params(DH_METHOD *dhm,
  41. int (*generate_params)(DH *, int, int, BN_GENCB *));
  42. =head1 DESCRIPTION
  43. The B<DH_METHOD> type is a structure used for the provision of custom DH
  44. implementations. It provides a set of functions used by OpenSSL for the
  45. implementation of the various DH capabilities.
  46. DH_meth_new() creates a new B<DH_METHOD> structure. It should be given a
  47. unique B<name> and a set of B<flags>. The B<name> should be a NULL terminated
  48. string, which will be duplicated and stored in the B<DH_METHOD> object. It is
  49. the callers responsibility to free the original string. The flags will be used
  50. during the construction of a new B<DH> object based on this B<DH_METHOD>. Any
  51. new B<DH> object will have those flags set by default.
  52. DH_meth_dup() creates a duplicate copy of the B<DH_METHOD> object passed as a
  53. parameter. This might be useful for creating a new B<DH_METHOD> based on an
  54. existing one, but with some differences.
  55. DH_meth_free() destroys a B<DH_METHOD> structure and frees up any memory
  56. associated with it.
  57. DH_meth_get0_name() will return a pointer to the name of this DH_METHOD. This
  58. is a pointer to the internal name string and so should not be freed by the
  59. caller. DH_meth_set1_name() sets the name of the DH_METHOD to B<name>. The
  60. string is duplicated and the copy is stored in the DH_METHOD structure, so the
  61. caller remains responsible for freeing the memory associated with the name.
  62. DH_meth_get_flags() returns the current value of the flags associated with this
  63. DH_METHOD. DH_meth_set_flags() provides the ability to set these flags.
  64. The functions DH_meth_get0_app_data() and DH_meth_set0_app_data() provide the
  65. ability to associate implementation specific data with the DH_METHOD. It is
  66. the application's responsibility to free this data before the DH_METHOD is
  67. freed via a call to DH_meth_free().
  68. DH_meth_get_generate_key() and DH_meth_set_generate_key() get and set the
  69. function used for generating a new DH key pair respectively. This function will
  70. be called in response to the application calling DH_generate_key(). The
  71. parameter for the function has the same meaning as for DH_generate_key().
  72. DH_meth_get_compute_key() and DH_meth_set_compute_key() get and set the
  73. function used for computing a new DH shared secret respectively. This function
  74. will be called in response to the application calling DH_compute_key(). The
  75. parameters for the function have the same meaning as for DH_compute_key().
  76. DH_meth_get_bn_mod_exp() and DH_meth_set_bn_mod_exp() get and set the function
  77. used for computing the following value:
  78. r = a ^ p mod m
  79. This function will be called by the default OpenSSL function for
  80. DH_generate_key(). The result is stored in the B<r> parameter. This function
  81. may be NULL unless using the default generate key function, in which case it
  82. must be present.
  83. DH_meth_get_init() and DH_meth_set_init() get and set the function used
  84. for creating a new DH instance respectively. This function will be
  85. called in response to the application calling DH_new() (if the current default
  86. DH_METHOD is this one) or DH_new_method(). The DH_new() and DH_new_method()
  87. functions will allocate the memory for the new DH object, and a pointer to this
  88. newly allocated structure will be passed as a parameter to the function. This
  89. function may be NULL.
  90. DH_meth_get_finish() and DH_meth_set_finish() get and set the function used
  91. for destroying an instance of a DH object respectively. This function will be
  92. called in response to the application calling DH_free(). A pointer to the DH
  93. to be destroyed is passed as a parameter. The destroy function should be used
  94. for DH implementation specific clean up. The memory for the DH itself should
  95. not be freed by this function. This function may be NULL.
  96. DH_meth_get_generate_params() and DH_meth_set_generate_params() get and set the
  97. function used for generating DH parameters respectively. This function will be
  98. called in response to the application calling DH_generate_parameters_ex() (or
  99. DH_generate_parameters()). The parameters for the function have the same
  100. meaning as for DH_generate_parameters_ex(). This function may be NULL.
  101. =head1 RETURN VALUES
  102. DH_meth_new() and DH_meth_dup() return the newly allocated DH_METHOD object
  103. or NULL on failure.
  104. DH_meth_get0_name() and DH_meth_get_flags() return the name and flags
  105. associated with the DH_METHOD respectively.
  106. All other DH_meth_get_*() functions return the appropriate function pointer
  107. that has been set in the DH_METHOD, or NULL if no such pointer has yet been
  108. set.
  109. DH_meth_set1_name() and all DH_meth_set_*() functions return 1 on success or
  110. 0 on failure.
  111. =head1 SEE ALSO
  112. L<DH_new(3)>, L<DH_new(3)>, L<DH_generate_parameters(3)>, L<DH_generate_key(3)>,
  113. L<DH_set_method(3)>, L<DH_size(3)>, L<DH_get0_pqg(3)>
  114. =head1 HISTORY
  115. The functions described here were added in OpenSSL 1.1.0.
  116. =head1 COPYRIGHT
  117. Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
  118. Licensed under the OpenSSL license (the "License"). You may not use
  119. this file except in compliance with the License. You can obtain a copy
  120. in the file LICENSE in the source distribution or at
  121. L<https://www.openssl.org/source/license.html>.
  122. =cut