1EVP_PKEY_GETTABLE_PARAMS(3ossl) OpenSSL EVP_PKEY_GETTABLE_PARAMS(3ossl)
2
6 EVP_PKEY_gettable_params, EVP_PKEY_get_params, EVP_PKEY_get_int_param,
7 EVP_PKEY_get_size_t_param, EVP_PKEY_get_bn_param,
8 EVP_PKEY_get_utf8_string_param, EVP_PKEY_get_octet_string_param -
9 retrieve key parameters from a key
10
12 #include <openssl/evp.h>
13 const OSSL_PARAM *EVP_PKEY_gettable_params(EVP_PKEY *pkey);
15 int EVP_PKEY_get_params(const EVP_PKEY *pkey, OSSL_PARAM params[]);
16 int EVP_PKEY_get_int_param(const EVP_PKEY *pkey, const char *key_name,
17 int *out);
18 int EVP_PKEY_get_size_t_param(const EVP_PKEY *pkey, const char *key_name,
19 size_t *out);
20 int EVP_PKEY_get_bn_param(const EVP_PKEY *pkey, const char *key_name,
21 BIGNUM **bn);
22 int EVP_PKEY_get_utf8_string_param(const EVP_PKEY *pkey, const char *key_name,
23 char *str, size_t max_buf_sz,
24 size_t *out_len);
25 int EVP_PKEY_get_octet_string_param(const EVP_PKEY *pkey, const char *key_name,
26 unsigned char *buf, size_t max_buf_sz,
27 size_t *out_len);
28
30 EVP_PKEY_get_params() retrieves parameters from the key pkey, according
31 to the contents of params. See OSSL_PARAM(3) for information about
32 parameters.
33 EVP_PKEY_gettable_params() returns a constant list of params indicating
35 the names and types of key parameters that can be retrieved. See
36 OSSL_PARAM(3) for information about parameters.
37 An OSSL_PARAM of type OSSL_PARAM_INTEGER or OSSL_PARAM_UNSIGNED_INTEGER
39 is of arbitrary length. Such a parameter can be obtained using any of
40 the functions EVP_PKEY_get_int_param(), EVP_PKEY_get_size_t_param() or
41 EVP_PKEY_get_bn_param(). Attempting to obtain an integer value that
42 does not fit into a native C int type will cause
43 EVP_PKEY_get_int_param() to fail. Similarly attempting to obtain an
44 integer value that is negative or does not fit into a native C size_t
45 type using EVP_PKEY_get_size_t_param() will also fail.
46 EVP_PKEY_get_int_param() retrieves a key pkey integer value *out
48 associated with a name of key_name if it fits into "int" type. For
49 parameters that do not fit into "int" use EVP_PKEY_get_bn_param().
50 EVP_PKEY_get_size_t_param() retrieves a key pkey size_t value *out
52 associated with a name of key_name if it fits into "size_t" type. For
53 parameters that do not fit into "size_t" use EVP_PKEY_get_bn_param().
54 EVP_PKEY_get_bn_param() retrieves a key pkey BIGNUM value **bn
56 associated with a name of key_name. If *bn is NULL then the BIGNUM is
57 allocated by the method.
58 EVP_PKEY_get_utf8_string_param() get a key pkey UTF8 string value into
60 a buffer str of maximum size max_buf_sz associated with a name of
61 key_name. The maximum size must be large enough to accomodate the
62 string value including a terminating NUL byte, or this function will
63 fail. If out_len is not NULL, *out_len is set to the length of the
64 string not including the terminating NUL byte. The required buffer size
65 not including the terminating NUL byte can be obtained from *out_len by
66 calling the function with str set to NULL.
67 EVP_PKEY_get_octet_string_param() get a key pkey's octet string value
69 into a buffer buf of maximum size max_buf_sz associated with a name of
70 key_name. If out_len is not NULL, *out_len is set to the length of the
71 contents. The required buffer size can be obtained from *out_len by
72 calling the function with buf set to NULL.
73
75 These functions only work for EVP_PKEYs that contain a provider side
76 key.
77
79 EVP_PKEY_gettable_params() returns NULL on error or if it is not
80 supported.
81 All other methods return 1 if a value associated with the key's
83 key_name was successfully returned, or 0 if there was an error. An
84 error may be returned by methods EVP_PKEY_get_utf8_string_param() and
85 EVP_PKEY_get_octet_string_param() if max_buf_sz is not big enough to
86 hold the value. If out_len is not NULL, *out_len will be assigned the
87 required buffer size to hold the value.
88
90 #include <openssl/evp.h>
91 char *curve_name[64];
93 unsigned char pub[256];
94 BIGNUM *bn_priv = NULL;
95 /*
97 * NB: assumes 'key' is set up before the next step. In this example the key
98 * is an EC key.
99 */
100 if (!EVP_PKEY_get_utf8_string_param(key, OSSL_PKEY_PARAM_GROUP_NAME,
102 curve_name, sizeof(curve_name), &len)) {
103 /* Error */
104 }
105 if (!EVP_PKEY_get_octet_string_param(key, OSSL_PKEY_PARAM_PUB_KEY,
106 pub, sizeof(pub), &len)) {
107 /* Error */
108 }
109 if (!EVP_PKEY_get_bn_param(key, OSSL_PKEY_PARAM_PRIV_KEY, &bn_priv)) {
110 /* Error */
111 }
112 BN_clear_free(bn_priv);
115
117 EVP_PKEY_CTX_new(3), provider-keymgmt(7), OSSL_PARAM(3)
118
120 These functions were added in OpenSSL 3.0.
121
123 Copyright 2020-2022 The OpenSSL Project Authors. All Rights Reserved.
124 Licensed under the Apache License 2.0 (the "License"). You may not use
126 this file except in compliance with the License. You can obtain a copy
127 in the file LICENSE in the source distribution or at
128 <https://www.openssl.org/source/license.html>.
1293.0.5 2022-11-01 EVP_PKEY_GETTABLE_PARAMS(3ossl)