5 EVP_PKEY_is_a, EVP_PKEY_can_sign, EVP_PKEY_typenames_do_all,
6 EVP_PKEY_get0_first_alg_name
7 - key type and capabilities functions
11 #include <openssl/evp.h>
13 int EVP_PKEY_is_a(const EVP_PKEY *pkey, const char *name);
14 int EVP_PKEY_can_sign(const EVP_PKEY *pkey);
15 int EVP_PKEY_typenames_do_all(const EVP_PKEY *pkey,
16 void (*fn)(const char *name, void *data),
18 const char *EVP_PKEY_get0_first_alg_name(const EVP_PKEY *key);
22 EVP_PKEY_is_a() checks if the key type of I<pkey> is I<name>.
24 EVP_PKEY_can_sign() checks if the functionality for the key type of
25 I<pkey> supports signing. No other check is done, such as whether
26 I<pkey> contains a private key.
28 EVP_PKEY_typenames_do_all() traverses all names for I<pkey>'s key type, and
29 calls I<fn> with each name and I<data>. For example, an RSA B<EVP_PKEY> may
30 be named both C<RSA> and C<rsaEncryption>.
31 The order of the names is undefined.
33 EVP_PKEY_get0_first_alg_name() returns the first algorithm name that is found
34 for the given I<pkey>. Note that the I<pkey> may have multiple synonyms
35 associated with it. In this case it is undefined which one will be returned.
36 Ownership of the returned string is retained by the I<pkey> object and should
37 not be freed by the caller.
41 EVP_PKEY_is_a() returns 1 if I<pkey> has the key type I<name>,
44 EVP_PKEY_can_sign() returns 1 if the I<pkey> key type functionality
45 supports signing, otherwise 0.
47 EVP_PKEY_get0_first_alg_name() returns the name that is found or NULL on error.
49 EVP_PKEY_typenames_do_all() returns 1 if the callback was called for all names.
50 A return value of 0 means that the callback was not called for any names.
54 =head2 EVP_PKEY_is_a()
56 The loaded providers and what key types they support will ultimately
57 determine what I<name> is possible to use with EVP_PKEY_is_a(). We do know
58 that the default provider supports RSA, DH, DSA and EC keys, so we can use
59 this as an crude example:
61 #include <openssl/evp.h>
64 /* |pkey| is an EVP_PKEY* */
65 if (EVP_PKEY_is_a(pkey, "RSA")) {
66 BIGNUM *modulus = NULL;
67 if (EVP_PKEY_get_bn_param(pkey, "n", &modulus))
68 /* do whatever with the modulus */
72 =head2 EVP_PKEY_can_sign()
74 #include <openssl/evp.h>
77 /* |pkey| is an EVP_PKEY* */
78 if (!EVP_PKEY_can_sign(pkey)) {
79 fprintf(stderr, "Not a signing key!");
82 /* Sign something... */
86 The functions described here were added in OpenSSL 3.0.
90 Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
92 Licensed under the Apache License 2.0 (the "License"). You may not use
93 this file except in compliance with the License. You can obtain a copy
94 in the file LICENSE in the source distribution or at
95 L<https://www.openssl.org/source/license.html>.