1EVP_PKEY_CTX_NEW(3ossl)             OpenSSL            EVP_PKEY_CTX_NEW(3ossl)
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NAME

6       EVP_PKEY_CTX_new, EVP_PKEY_CTX_new_id, EVP_PKEY_CTX_new_from_name,
7       EVP_PKEY_CTX_new_from_pkey, EVP_PKEY_CTX_dup, EVP_PKEY_CTX_free,
8       EVP_PKEY_CTX_is_a - public key algorithm context functions
9

SYNOPSIS

11        #include <openssl/evp.h>
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13        EVP_PKEY_CTX *EVP_PKEY_CTX_new(EVP_PKEY *pkey, ENGINE *e);
14        EVP_PKEY_CTX *EVP_PKEY_CTX_new_id(int id, ENGINE *e);
15        EVP_PKEY_CTX *EVP_PKEY_CTX_new_from_name(OSSL_LIB_CTX *libctx,
16                                                 const char *name,
17                                                 const char *propquery);
18        EVP_PKEY_CTX *EVP_PKEY_CTX_new_from_pkey(OSSL_LIB_CTX *libctx,
19                                                 EVP_PKEY *pkey,
20                                                 const char *propquery);
21        EVP_PKEY_CTX *EVP_PKEY_CTX_dup(const EVP_PKEY_CTX *ctx);
22        void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx);
23        int EVP_PKEY_CTX_is_a(EVP_PKEY_CTX *ctx, const char *keytype);
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DESCRIPTION

26       The EVP_PKEY_CTX_new() function allocates public key algorithm context
27       using the pkey key type and ENGINE e.
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29       The EVP_PKEY_CTX_new_id() function allocates public key algorithm
30       context using the key type specified by id and ENGINE e.
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32       The EVP_PKEY_CTX_new_from_name() function allocates a public key
33       algorithm context using the library context libctx (see
34       OSSL_LIB_CTX(3)), the key type specified by name and the property query
35       propquery.  None of the arguments are duplicated, so they  must remain
36       unchanged for the lifetime of the returned EVP_PKEY_CTX or of any of
37       its duplicates.  Read further about the possible names in "NOTES"
38       below.
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40       The EVP_PKEY_CTX_new_from_pkey() function allocates a public key
41       algorithm context using the library context libctx (see
42       OSSL_LIB_CTX(3)) and the algorithm specified by pkey and the property
43       query propquery. None of the arguments are duplicated, so they must
44       remain unchanged for the lifetime of the returned EVP_PKEY_CTX or any
45       of its duplicates.
46
47       EVP_PKEY_CTX_new_id() and EVP_PKEY_CTX_new_from_name() are normally
48       used when no EVP_PKEY structure is associated with the operations, for
49       example during parameter generation or key generation for some
50       algorithms.
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52       EVP_PKEY_CTX_dup() duplicates the context ctx. It is not supported for
53       a keygen operation.
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55       EVP_PKEY_CTX_free() frees up the context ctx.  If ctx is NULL, nothing
56       is done.
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58       EVP_PKEY_is_a() checks if the key type associated with ctx is keytype.
59

NOTES

61   On EVP_PKEY_CTX
62       The EVP_PKEY_CTX structure is an opaque public key algorithm context
63       used by the OpenSSL high-level public key API. Contexts MUST NOT be
64       shared between threads: that is it is not permissible to use the same
65       context simultaneously in two threads.
66
67   On Key Types
68       We mention "key type" in this manual, which is the same as "algorithm"
69       in most cases, allowing either term to be used interchangeably.  There
70       are algorithms where the key type and the algorithm of the operations
71       that use the keys are not the same, such as EC keys being used for
72       ECDSA and ECDH operations.
73
74       Key types are given in two different manners:
75
76       Legacy NID or EVP_PKEY type
77           This is the id used with EVP_PKEY_CTX_new_id().
78
79           These are EVP_PKEY_RSA, EVP_PKEY_RSA_PSS, EVP_PKEY_DSA,
80           EVP_PKEY_DH, EVP_PKEY_EC, EVP_PKEY_SM2, EVP_PKEY_X25519,
81           EVP_PKEY_X448, and are used by legacy methods.
82
83       Name strings
84           This is the name used with EVP_PKEY_CTX_new_from_name().
85
86           These are names like "RSA", "DSA", and what's available depends on
87           what providers are currently accessible.
88
89           The OpenSSL providers offer a set of key types available this way,
90           please see OSSL_PROVIDER-FIPS(7) and OSSL_PROVIDER-default(7) and
91           related documentation for more information.
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RETURN VALUES

94       EVP_PKEY_CTX_new(), EVP_PKEY_CTX_new_id() and EVP_PKEY_CTX_dup() return
95       either the newly allocated EVP_PKEY_CTX structure or NULL if an error
96       occurred.
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98       EVP_PKEY_CTX_free() does not return a value.
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100       EVP_PKEY_CTX_is_a() returns 1 for true and 0 for false.
101

SEE ALSO

103       EVP_PKEY_new(3)
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HISTORY

106       The EVP_PKEY_CTX_new(), EVP_PKEY_CTX_new_id(), EVP_PKEY_CTX_dup() and
107       EVP_PKEY_CTX_free() functions were added in OpenSSL 1.0.0.
108
109       The EVP_PKEY_CTX_new_from_name() and EVP_PKEY_CTX_new_from_pkey()
110       functions were added in OpenSSL 3.0.
111

113       Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved.
114
115       Licensed under the Apache License 2.0 (the "License").  You may not use
116       this file except in compliance with the License.  You can obtain a copy
117       in the file LICENSE in the source distribution or at
118       <https://www.openssl.org/source/license.html>.
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1223.0.5                             2022-11-01           EVP_PKEY_CTX_NEW(3ossl)
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