doc/man3/OSSL_DECODER_CTX_new_by_EVP_PKEY.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 OSSL_DECODER_CTX_new_by_EVP_PKEY,
   6 OSSL_DECODER_CTX_set_passphrase,
   7 OSSL_DECODER_CTX_set_pem_password_cb,
   8 OSSL_DECODER_CTX_set_passphrase_ui,
   9 OSSL_DECODER_CTX_set_passphrase_cb
  10 - Decoder routines to decode EVP_PKEYs
  11
  12 =head1 SYNOPSIS
  13
  14  #include <openssl/decoder.h>
  15
  16  OSSL_DECODER_CTX *
  17  OSSL_DECODER_CTX_new_by_EVP_PKEY(const EVP_PKEY *pkey, const char *input_type,
  18                                   OPENSSL_CTX *libctx, const char *propquery);
  19
  20  int OSSL_DECODER_CTX_set_passphrase(OSSL_DECODER_CTX *ctx,
  21                                      const unsigned char *kstr,
  22                                      size_t klen);
  23  int OSSL_DECODER_CTX_set_pem_password_cb(OSSL_DECODER_CTX *ctx,
  24                                           pem_password_cb *cb,
  25                                           void *cbarg);
  26  int OSSL_DECODER_CTX_set_passphrase_ui(OSSL_DECODER_CTX *ctx,
  27                                         const UI_METHOD *ui_method,
  28                                         void *ui_data);
  29  int OSSL_DECODER_CTX_set_passphrase_cb(OSSL_DECODER_CTX *ctx,
  30                                         OSSL_PASSPHRASE_CALLBACK *cb,
  31                                         void *cbarg);
  32
  33 =head1 DESCRIPTION
  34
  35 OSSL_DECODER_CTX_new_by_EVP_PKEY() is a utility function that
  36 creates a B<OSSL_DECODER_CTX>, finds all applicable decoder
  37 implementations and sets them up, so all the caller has to do next is
  38 call functions like OSSL_DECODE_from_bio().
  39
  40 Internally OSSL_DECODER_CTX_new_by_EVP_PKEY() searches for all
  41 available L<EVP_KEYMGMT(3)> implementations, and then builds a list of all
  42 potential decoder implementations that may be able to process the
  43 encoded input into data suitable for B<EVP_PKEY>s.  All these
  44 implementations are implicitly fetched using I<libctx> and I<propquery>.
  45
  46 The search of decoder implementations can be limited with
  47 I<input_type>, which specifies a starting input type.  This is further
  48 explained in L<OSSL_DECODER_CTX_set_input_type(3)>.
  49
  50 If no suitable decoder was found, OSSL_DECODER_CTX_new_by_EVP_PKEY()
  51 still creates a B<OSSL_DECODER_CTX>, but with no associated
  52 decoder (L<OSSL_DECODER_CTX_num_decoders(3)> returns
  53 zero).  This helps the caller distinguish between an error when
  54 creating the B<OSSL_DECODER_CTX>, and the lack the decoder
  55 support and act accordingly.
  56
  57 OSSL_DECODER_CTX_set_passphrase() gives the implementation a
  58 pass phrase to use when decrypting the encoded private key.
  59 Alternatively, a pass phrase callback may be specified with the
  60 following functions.
  61
  62 OSSL_DECODER_CTX_set_pem_password_cb(),
  63 OSSL_DECODER_CTX_set_passphrase_ui() and
  64 OSSL_DECODER_CTX_set_passphrase_cb() set up a callback method that
  65 the implementation can use to prompt for a pass phrase, giving the caller
  66 the choice of prefered pass phrase callback form.  These are called
  67 indirectly, through an internal B<OSSL_PASSPHRASE_CALLBACK> function.
  68
  69 The internal B<OSSL_PASSPHRASE_CALLBACK> function caches the pass phrase,
  70 to be re-used in all decodings that are performed in the same decoding run
  71 (for example, within one L<OSSL_DECODER_from_bio(3)> call).
  72
  73 =head1 RETURN VALUES
  74
  75 OSSL_DECODER_CTX_new_by_EVP_PKEY() returns a pointer to a
  76 B<OSSL_DECODER_CTX>, or NULL if it couldn't be created.
  77
  78 OSSL_DECODER_CTX_set_passphrase(),
  79 OSSL_DECODER_CTX_set_pem_password_cb(),
  80 OSSL_DECODER_CTX_set_passphrase_ui() and
  81 OSSL_DECODER_CTX_set_passphrase_cb()
  82 all return 1 on success, or 0 on failure.
  83
  84 =head1 NOTES
  85
  86 Parts of the function names are made to match already existing OpenSSL
  87 names.
  88
  89 B<EVP_PKEY> in OSSL_DECODER_CTX_new_by_EVP_PKEY() matches the type
  90 name, thus making for the naming pattern
  91 B<OSSL_DECODER_CTX_new_by_I<TYPE>>() when new types are handled.
  92
  93 =head1 SEE ALSO
  94
  95 L<provider(7)>, L<OSSL_DECODER(3)>, L<OSSL_DECODER_CTX(3)>
  96
  97 =head1 HISTORY
  98
  99 The functions described here were added in OpenSSL 3.0.
 100
 101 =head1 COPYRIGHT
 102
 103 Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
 104
 105 Licensed under the Apache License 2.0 (the "License").  You may not use
 106 this file except in compliance with the License.  You can obtain a copy
 107 in the file LICENSE in the source distribution or at
 108 L<https://www.openssl.org/source/license.html>.
 109
 110 =cut