1PROVIDER-KDF(7ossl) OpenSSL PROVIDER-KDF(7ossl)
2
6 provider-kdf - The KDF library <-> provider functions
7
9 #include <openssl/core_dispatch.h>
10 #include <openssl/core_names.h>
11 /*
13 * None of these are actual functions, but are displayed like this for
14 * the function signatures for functions that are offered as function
15 * pointers in OSSL_DISPATCH arrays.
16 */
17 /* Context management */
19 void *OSSL_FUNC_kdf_newctx(void *provctx);
20 void OSSL_FUNC_kdf_freectx(void *kctx);
21 void *OSSL_FUNC_kdf_dupctx(void *src);
22 /* Encryption/decryption */
24 int OSSL_FUNC_kdf_reset(void *kctx);
25 int OSSL_FUNC_kdf_derive(void *kctx, unsigned char *key, size_t keylen,
26 const OSSL_PARAM params[]);
27 /* KDF parameter descriptors */
29 const OSSL_PARAM *OSSL_FUNC_kdf_gettable_params(void *provctx);
30 const OSSL_PARAM *OSSL_FUNC_kdf_gettable_ctx_params(void *kcxt, void *provctx);
31 const OSSL_PARAM *OSSL_FUNC_kdf_settable_ctx_params(void *kcxt, void *provctx);
32 /* KDF parameters */
34 int OSSL_FUNC_kdf_get_params(OSSL_PARAM params[]);
35 int OSSL_FUNC_kdf_get_ctx_params(void *kctx, OSSL_PARAM params[]);
36 int OSSL_FUNC_kdf_set_ctx_params(void *kctx, const OSSL_PARAM params[]);
37
39 This documentation is primarily aimed at provider authors. See
40 provider(7) for further information.
41 The KDF operation enables providers to implement KDF algorithms and
43 make them available to applications via the API functions
44 EVP_KDF_CTX_reset(3), and EVP_KDF_derive(3).
45 All "functions" mentioned here are passed as function pointers between
47 libcrypto and the provider in OSSL_DISPATCH arrays via OSSL_ALGORITHM
48 arrays that are returned by the provider's provider_query_operation()
49 function (see "Provider Functions" in provider-base(7)).
50 All these "functions" have a corresponding function type definition
52 named OSSL_FUNC_{name}_fn, and a helper function to retrieve the
53 function pointer from an OSSL_DISPATCH element named OSSL_FUNC_{name}.
54 For example, the "function" OSSL_FUNC_kdf_newctx() has these:
55 typedef void *(OSSL_FUNC_kdf_newctx_fn)(void *provctx);
57 static ossl_inline OSSL_FUNC_kdf_newctx_fn
58 OSSL_FUNC_kdf_newctx(const OSSL_DISPATCH *opf);
59 OSSL_DISPATCH array entries are identified by numbers that are provided
61 as macros in openssl-core_dispatch.h(7), as follows:
62 OSSL_FUNC_kdf_newctx OSSL_FUNC_KDF_NEWCTX
64 OSSL_FUNC_kdf_freectx OSSL_FUNC_KDF_FREECTX
65 OSSL_FUNC_kdf_dupctx OSSL_FUNC_KDF_DUPCTX
66 OSSL_FUNC_kdf_reset OSSL_FUNC_KDF_RESET
68 OSSL_FUNC_kdf_derive OSSL_FUNC_KDF_DERIVE
69 OSSL_FUNC_kdf_get_params OSSL_FUNC_KDF_GET_PARAMS
71 OSSL_FUNC_kdf_get_ctx_params OSSL_FUNC_KDF_GET_CTX_PARAMS
72 OSSL_FUNC_kdf_set_ctx_params OSSL_FUNC_KDF_SET_CTX_PARAMS
73 OSSL_FUNC_kdf_gettable_params OSSL_FUNC_KDF_GETTABLE_PARAMS
75 OSSL_FUNC_kdf_gettable_ctx_params OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS
76 OSSL_FUNC_kdf_settable_ctx_params OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS
77 A KDF algorithm implementation may not implement all of these
79 functions. In order to be a consistent set of functions, at least the
80 following functions must be implemented: OSSL_FUNC_kdf_newctx(),
81 OSSL_FUNC_kdf_freectx(), OSSL_FUNC_kdf_set_ctx_params(),
82 OSSL_FUNC_kdf_derive(). All other functions are optional.
83 Context Management Functions
85 OSSL_FUNC_kdf_newctx() should create and return a pointer to a provider
86 side structure for holding context information during a KDF operation.
87 A pointer to this context will be passed back in a number of the other
88 KDF operation function calls. The parameter provctx is the provider
89 context generated during provider initialisation (see provider(7)).
90 OSSL_FUNC_kdf_freectx() is passed a pointer to the provider side KDF
92 context in the kctx parameter. If it receives NULL as kctx value, it
93 should not do anything other than return. This function should free
94 any resources associated with that context.
95 OSSL_FUNC_kdf_dupctx() should duplicate the provider side KDF context
97 in the kctx parameter and return the duplicate copy.
98 Encryption/Decryption Functions
100 OSSL_FUNC_kdf_reset() initialises a KDF operation given a provider side
101 KDF context in the kctx parameter.
102 OSSL_FUNC_kdf_derive() performs the KDF operation after processing the
104 params as per OSSL_FUNC_kdf_set_ctx_params(). The kctx parameter
105 contains a pointer to the provider side context. The resulting key of
106 the desired keylen should be written to key. If the algorithm does not
107 support the requested keylen the function must return error.
108 KDF Parameters
110 See OSSL_PARAM(3) for further details on the parameters structure used
111 by these functions.
112 OSSL_FUNC_kdf_get_params() gets details of parameter values associated
114 with the provider algorithm and stores them in params.
115 OSSL_FUNC_kdf_set_ctx_params() sets KDF parameters associated with the
117 given provider side KDF context kctx to params. Any parameter settings
118 are additional to any that were previously set. Passing NULL for
119 params should return true.
120 OSSL_FUNC_kdf_get_ctx_params() retrieves gettable parameter values
122 associated with the given provider side KDF context kctx and stores
123 them in params. Passing NULL for params should return true.
124 OSSL_FUNC_kdf_gettable_params(), OSSL_FUNC_kdf_gettable_ctx_params(),
126 and OSSL_FUNC_kdf_settable_ctx_params() all return constant OSSL_PARAM
127 arrays as descriptors of the parameters that
128 OSSL_FUNC_kdf_get_params(), OSSL_FUNC_kdf_get_ctx_params(), and
129 OSSL_FUNC_kdf_set_ctx_params() can handle, respectively.
130 OSSL_FUNC_kdf_gettable_ctx_params() and
131 OSSL_FUNC_kdf_settable_ctx_params() will return the parameters
132 associated with the provider side context kctx in its current state if
133 it is not NULL. Otherwise, they return the parameters associated with
134 the provider side algorithm provctx.
135 Parameters currently recognised by built-in KDFs are as follows. Not
137 all parameters are relevant to, or are understood by all KDFs:
138 "size" (OSSL_KDF_PARAM_SIZE) <unsigned integer>
140 Gets the output size from the associated KDF ctx. If the algorithm
141 produces a variable amount of output, SIZE_MAX should be returned.
142 If the input parameters required to calculate the fixed output size
143 have not yet been supplied, 0 should be returned indicating an
144 error.
145 "key" (OSSL_KDF_PARAM_KEY) <octet string>
147 Sets the key in the associated KDF ctx.
148 "secret" (OSSL_KDF_PARAM_SECRET) <octet string>
150 Sets the secret in the associated KDF ctx.
151 "pass" (OSSL_KDF_PARAM_PASSWORD) <octet string>
153 Sets the password in the associated KDF ctx.
154 "cipher" (OSSL_KDF_PARAM_CIPHER) <UTF8 string>
156 "digest" (OSSL_KDF_PARAM_DIGEST) <UTF8 string>
157 "mac" (OSSL_KDF_PARAM_MAC) <UTF8 string>
158 Sets the name of the underlying cipher, digest or MAC to be used.
159 It must name a suitable algorithm for the KDF that's being used.
160 "maclen" (OSSL_KDF_PARAM_MAC_SIZE) <octet string>
162 Sets the length of the MAC in the associated KDF ctx.
163 "properties" (OSSL_KDF_PARAM_PROPERTIES) <UTF8 string>
165 Sets the properties to be queried when trying to fetch the
166 underlying algorithm. This must be given together with the
167 algorithm naming parameter to be considered valid.
168 "iter" (OSSL_KDF_PARAM_ITER) <unsigned integer>
170 Sets the number of iterations in the associated KDF ctx.
171 "mode" (OSSL_KDF_PARAM_MODE) <UTF8 string>
173 Sets the mode in the associated KDF ctx.
174 "pkcs5" (OSSL_KDF_PARAM_PKCS5) <integer>
176 Enables or diables the SP800-132 compliance checks. A mode of 0
177 enables the compliance checks.
178 The checks performed are:
180 - the iteration count is at least 1000.
182 - the salt length is at least 128 bits.
183 - the derived key length is at least 112 bits.
184 "ukm" (OSSL_KDF_PARAM_UKM) <octet string>
185 Sets an optional random string that is provided by the sender
186 called "partyAInfo". In CMS this is the user keying material.
187 "cekalg" (OSSL_KDF_PARAM_CEK_ALG) <UTF8 string>
189 Sets the CEK wrapping algorithm name in the associated KDF ctx.
190 "n" (OSSL_KDF_PARAM_SCRYPT_N) <unsigned integer>
192 Sets the scrypt work factor parameter N in the associated KDF ctx.
193 "r" (OSSL_KDF_PARAM_SCRYPT_R) <unsigned integer>
195 Sets the scrypt work factor parameter r in the associated KDF ctx.
196 "p" (OSSL_KDF_PARAM_SCRYPT_P) <unsigned integer>
198 Sets the scrypt work factor parameter p in the associated KDF ctx.
199 "maxmem_bytes" (OSSL_KDF_PARAM_SCRYPT_MAXMEM) <unsigned integer>
201 Sets the scrypt work factor parameter maxmem in the associated KDF
202 ctx.
203 "prefix" (OSSL_KDF_PARAM_PREFIX) <octet string>
205 Sets the prefix string using by the TLS 1.3 version of HKDF in the
206 associated KDF ctx.
207 "label" (OSSL_KDF_PARAM_LABEL) <octet string>
209 Sets the label string using by the TLS 1.3 version of HKDF in the
210 associated KDF ctx.
211 "data" (OSSL_KDF_PARAM_DATA) <octet string>
213 Sets the context string using by the TLS 1.3 version of HKDF in the
214 associated KDF ctx.
215 "info" (OSSL_KDF_PARAM_INFO) <octet string>
217 Sets the optional shared info in the associated KDF ctx.
218 "seed" (OSSL_KDF_PARAM_SEED) <octet string>
220 Sets the IV in the associated KDF ctx.
221 "xcghash" (OSSL_KDF_PARAM_SSHKDF_XCGHASH) <octet string>
223 Sets the xcghash in the associated KDF ctx.
224 "session_id" (OSSL_KDF_PARAM_SSHKDF_SESSION_ID) <octet string>
226 Sets the session ID in the associated KDF ctx.
227 "type" (OSSL_KDF_PARAM_SSHKDF_TYPE) <UTF8 string>
229 Sets the SSH KDF type parameter in the associated KDF ctx. There
230 are six supported types:
231 EVP_KDF_SSHKDF_TYPE_INITIAL_IV_CLI_TO_SRV
233 The Initial IV from client to server. A single char of value
234 65 (ASCII char 'A').
235 EVP_KDF_SSHKDF_TYPE_INITIAL_IV_SRV_TO_CLI
237 The Initial IV from server to client A single char of value 66
238 (ASCII char 'B').
239 EVP_KDF_SSHKDF_TYPE_ENCRYPTION_KEY_CLI_TO_SRV
241 The Encryption Key from client to server A single char of value
242 67 (ASCII char 'C').
243 EVP_KDF_SSHKDF_TYPE_ENCRYPTION_KEY_SRV_TO_CLI
245 The Encryption Key from server to client A single char of value
246 68 (ASCII char 'D').
247 EVP_KDF_SSHKDF_TYPE_INTEGRITY_KEY_CLI_TO_SRV
249 The Integrity Key from client to server A single char of value
250 69 (ASCII char 'E').
251 EVP_KDF_SSHKDF_TYPE_INTEGRITY_KEY_SRV_TO_CLI
253 The Integrity Key from client to server A single char of value
254 70 (ASCII char 'F').
255 "constant" (OSSL_KDF_PARAM_CONSTANT) <octet string>
257 Sets the constant value in the associated KDF ctx.
258 "id" (OSSL_KDF_PARAM_PKCS12_ID) <integer>
260 Sets the intended usage of the output bits in the associated KDF
261 ctx. It is defined as per RFC 7292 section B.3.
262
264 OSSL_FUNC_kdf_newctx() and OSSL_FUNC_kdf_dupctx() should return the
265 newly created provider side KDF context, or NULL on failure.
266 OSSL_FUNC_kdf_derive(), OSSL_FUNC_kdf_get_params(),
268 OSSL_FUNC_kdf_get_ctx_params() and OSSL_FUNC_kdf_set_ctx_params()
269 should return 1 for success or 0 on error.
270 OSSL_FUNC_kdf_gettable_params(), OSSL_FUNC_kdf_gettable_ctx_params()
272 and OSSL_FUNC_kdf_settable_ctx_params() should return a constant
273 OSSL_PARAM array, or NULL if none is offered.
274
276 The KDF life-cycle is described in life_cycle-kdf(7). Providers should
277 ensure that the various transitions listed there are supported. At
278 some point the EVP layer will begin enforcing the listed transitions.
279
281 provider(7), life_cycle-kdf(7), EVP_KDF(3).
282
284 The provider KDF interface was introduced in OpenSSL 3.0.
285
287 Copyright 2020-2022 The OpenSSL Project Authors. All Rights Reserved.
288 Licensed under the Apache License 2.0 (the "License"). You may not use
290 this file except in compliance with the License. You can obtain a copy
291 in the file LICENSE in the source distribution or at
292 <https://www.openssl.org/source/license.html>.
2933.0.5 2022-11-01 PROVIDER-KDF(7ossl)