EVP_ASYM_CIPHER_free.pod 4.8 KB

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  1. =pod
  2. =head1 NAME
  3. EVP_ASYM_CIPHER_fetch, EVP_ASYM_CIPHER_free, EVP_ASYM_CIPHER_up_ref,
  4. EVP_ASYM_CIPHER_is_a, EVP_ASYM_CIPHER_get0_provider,
  5. EVP_ASYM_CIPHER_do_all_provided, EVP_ASYM_CIPHER_names_do_all,
  6. EVP_ASYM_CIPHER_get0_name, EVP_ASYM_CIPHER_get0_description,
  7. EVP_ASYM_CIPHER_gettable_ctx_params, EVP_ASYM_CIPHER_settable_ctx_params
  8. - Functions to manage EVP_ASYM_CIPHER algorithm objects
  9. =head1 SYNOPSIS
  10. #include <openssl/evp.h>
  11. EVP_ASYM_CIPHER *EVP_ASYM_CIPHER_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
  12. const char *properties);
  13. void EVP_ASYM_CIPHER_free(EVP_ASYM_CIPHER *cipher);
  14. int EVP_ASYM_CIPHER_up_ref(EVP_ASYM_CIPHER *cipher);
  15. const char *EVP_ASYM_CIPHER_get0_name(const EVP_ASYM_CIPHER *cipher);
  16. int EVP_ASYM_CIPHER_is_a(const EVP_ASYM_CIPHER *cipher, const char *name);
  17. OSSL_PROVIDER *EVP_ASYM_CIPHER_get0_provider(const EVP_ASYM_CIPHER *cipher);
  18. void EVP_ASYM_CIPHER_do_all_provided(OSSL_LIB_CTX *libctx,
  19. void (*fn)(EVP_ASYM_CIPHER *cipher,
  20. void *arg),
  21. void *arg);
  22. int EVP_ASYM_CIPHER_names_do_all(const EVP_ASYM_CIPHER *cipher,
  23. void (*fn)(const char *name, void *data),
  24. void *data);
  25. const char *EVP_ASYM_CIPHER_get0_description(const EVP_ASYM_CIPHER *cipher);
  26. const OSSL_PARAM *EVP_ASYM_CIPHER_gettable_ctx_params(const EVP_ASYM_CIPHER *cip);
  27. const OSSL_PARAM *EVP_ASYM_CIPHER_settable_ctx_params(const EVP_ASYM_CIPHER *cip);
  28. =head1 DESCRIPTION
  29. EVP_ASYM_CIPHER_fetch() fetches the implementation for the given
  30. B<algorithm> from any provider offering it, within the criteria given
  31. by the B<properties> and in the scope of the given library context B<ctx> (see
  32. L<OSSL_LIB_CTX(3)>). The algorithm will be one offering functions for performing
  33. asymmetric cipher related tasks such as asymmetric encryption and decryption.
  34. See L<crypto(7)/ALGORITHM FETCHING> for further information.
  35. The returned value must eventually be freed with EVP_ASYM_CIPHER_free().
  36. EVP_ASYM_CIPHER_free() decrements the reference count for the B<EVP_ASYM_CIPHER>
  37. structure. Typically this structure will have been obtained from an earlier call
  38. to EVP_ASYM_CIPHER_fetch(). If the reference count drops to 0 then the
  39. structure is freed.
  40. EVP_ASYM_CIPHER_up_ref() increments the reference count for an
  41. B<EVP_ASYM_CIPHER> structure.
  42. EVP_ASYM_CIPHER_is_a() returns 1 if I<cipher> is an implementation of an
  43. algorithm that's identifiable with I<name>, otherwise 0.
  44. EVP_ASYM_CIPHER_get0_provider() returns the provider that I<cipher> was
  45. fetched from.
  46. EVP_ASYM_CIPHER_do_all_provided() traverses all EVP_ASYM_CIPHERs implemented by
  47. all activated providers in the given library context I<libctx>, and for each of
  48. the implementations, calls the given function I<fn> with the implementation
  49. method and the given I<arg> as argument.
  50. EVP_ASYM_CIPHER_get0_name() returns the algorithm name from the provided
  51. implementation for the given I<cipher>. Note that the I<cipher> may have
  52. multiple synonyms associated with it. In this case the first name from the
  53. algorithm definition is returned. Ownership of the returned string is retained
  54. by the I<cipher> object and should not be freed by the caller.
  55. EVP_ASYM_CIPHER_names_do_all() traverses all names for I<cipher>, and calls
  56. I<fn> with each name and I<data>.
  57. EVP_ASYM_CIPHER_get0_description() returns a description of the I<cipher>,
  58. meant for display and human consumption. The description is at the
  59. discretion of the I<cipher> implementation.
  60. EVP_ASYM_CIPHER_gettable_ctx_params() and EVP_ASYM_CIPHER_settable_ctx_params()
  61. return a constant B<OSSL_PARAM> array that describes the names and types of key
  62. parameters that can be retrieved or set by a key encryption algorithm using
  63. L<EVP_PKEY_CTX_get_params(3)> and L<EVP_PKEY_CTX_set_params(3)>.
  64. =head1 RETURN VALUES
  65. EVP_ASYM_CIPHER_fetch() returns a pointer to an B<EVP_ASYM_CIPHER> for success
  66. or B<NULL> for failure.
  67. EVP_ASYM_CIPHER_up_ref() returns 1 for success or 0 otherwise.
  68. EVP_ASYM_CIPHER_names_do_all() returns 1 if the callback was called for all
  69. names. A return value of 0 means that the callback was not called for any names.
  70. EVP_ASYM_CIPHER_gettable_ctx_params() and EVP_ASYM_CIPHER_settable_ctx_params()
  71. return a constant B<OSSL_PARAM> array or NULL on error.
  72. =head1 SEE ALSO
  73. L<crypto(7)/ALGORITHM FETCHING>, L<OSSL_PROVIDER(3)>
  74. =head1 HISTORY
  75. The functions described here were added in OpenSSL 3.0.
  76. =head1 COPYRIGHT
  77. Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
  78. Licensed under the Apache License 2.0 (the "License"). You may not use
  79. this file except in compliance with the License. You can obtain a copy
  80. in the file LICENSE in the source distribution or at
  81. L<https://www.openssl.org/source/license.html>.
  82. =cut