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(3) arrays via
48 OSSL_ALGORITHM(3) arrays that are returned by the provider's
49 provider_query_operation() function (see "Provider Functions" in
50 provider-base(7)).
51 All these "functions" have a corresponding function type definition
53 named OSSL_FUNC_{name}_fn, and a helper function to retrieve the
54 function pointer from an OSSL_DISPATCH(3) element named
55 OSSL_FUNC_{name}. For example, the "function" OSSL_FUNC_kdf_newctx()
56 has these:
57 typedef void *(OSSL_FUNC_kdf_newctx_fn)(void *provctx);
59 static ossl_inline OSSL_FUNC_kdf_newctx_fn
60 OSSL_FUNC_kdf_newctx(const OSSL_DISPATCH *opf);
61 OSSL_DISPATCH(3) array entries are identified by numbers that are
63 provided as macros in openssl-core_dispatch.h(7), as follows:
64 OSSL_FUNC_kdf_newctx OSSL_FUNC_KDF_NEWCTX
66 OSSL_FUNC_kdf_freectx OSSL_FUNC_KDF_FREECTX
67 OSSL_FUNC_kdf_dupctx OSSL_FUNC_KDF_DUPCTX
68 OSSL_FUNC_kdf_reset OSSL_FUNC_KDF_RESET
70 OSSL_FUNC_kdf_derive OSSL_FUNC_KDF_DERIVE
71 OSSL_FUNC_kdf_get_params OSSL_FUNC_KDF_GET_PARAMS
73 OSSL_FUNC_kdf_get_ctx_params OSSL_FUNC_KDF_GET_CTX_PARAMS
74 OSSL_FUNC_kdf_set_ctx_params OSSL_FUNC_KDF_SET_CTX_PARAMS
75 OSSL_FUNC_kdf_gettable_params OSSL_FUNC_KDF_GETTABLE_PARAMS
77 OSSL_FUNC_kdf_gettable_ctx_params OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS
78 OSSL_FUNC_kdf_settable_ctx_params OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS
79 A KDF algorithm implementation may not implement all of these
81 functions. In order to be a consistent set of functions, at least the
82 following functions must be implemented: OSSL_FUNC_kdf_newctx(),
83 OSSL_FUNC_kdf_freectx(), OSSL_FUNC_kdf_set_ctx_params(),
84 OSSL_FUNC_kdf_derive(). All other functions are optional.
85 Context Management Functions
87 OSSL_FUNC_kdf_newctx() should create and return a pointer to a provider
88 side structure for holding context information during a KDF operation.
89 A pointer to this context will be passed back in a number of the other
90 KDF operation function calls. The parameter provctx is the provider
91 context generated during provider initialisation (see provider(7)).
92 OSSL_FUNC_kdf_freectx() is passed a pointer to the provider side KDF
94 context in the kctx parameter. If it receives NULL as kctx value, it
95 should not do anything other than return. This function should free
96 any resources associated with that context.
97 OSSL_FUNC_kdf_dupctx() should duplicate the provider side KDF context
99 in the kctx parameter and return the duplicate copy.
100 Encryption/Decryption Functions
102 OSSL_FUNC_kdf_reset() initialises a KDF operation given a provider side
103 KDF context in the kctx parameter.
104 OSSL_FUNC_kdf_derive() performs the KDF operation after processing the
106 params as per OSSL_FUNC_kdf_set_ctx_params(). The kctx parameter
107 contains a pointer to the provider side context. The resulting key of
108 the desired keylen should be written to key. If the algorithm does not
109 support the requested keylen the function must return error.
110 KDF Parameters
112 See OSSL_PARAM(3) for further details on the parameters structure used
113 by these functions.
114 OSSL_FUNC_kdf_get_params() gets details of parameter values associated
116 with the provider algorithm and stores them in params.
117 OSSL_FUNC_kdf_set_ctx_params() sets KDF parameters associated with the
119 given provider side KDF context kctx to params. Any parameter settings
120 are additional to any that were previously set. Passing NULL for
121 params should return true.
122 OSSL_FUNC_kdf_get_ctx_params() retrieves gettable parameter values
124 associated with the given provider side KDF context kctx and stores
125 them in params. Passing NULL for params should return true.
126 OSSL_FUNC_kdf_gettable_params(), OSSL_FUNC_kdf_gettable_ctx_params(),
128 and OSSL_FUNC_kdf_settable_ctx_params() all return constant
129 OSSL_PARAM(3) arrays as descriptors of the parameters that
130 OSSL_FUNC_kdf_get_params(), OSSL_FUNC_kdf_get_ctx_params(), and
131 OSSL_FUNC_kdf_set_ctx_params() can handle, respectively.
132 OSSL_FUNC_kdf_gettable_ctx_params() and
133 OSSL_FUNC_kdf_settable_ctx_params() will return the parameters
134 associated with the provider side context kctx in its current state if
135 it is not NULL. Otherwise, they return the parameters associated with
136 the provider side algorithm provctx.
137 Parameters currently recognised by built-in KDFs are as follows. Not
139 all parameters are relevant to, or are understood by all KDFs:
140 "size" (OSSL_KDF_PARAM_SIZE) <unsigned integer>
142 Gets the output size from the associated KDF ctx. If the algorithm
143 produces a variable amount of output, SIZE_MAX should be returned.
144 If the input parameters required to calculate the fixed output size
145 have not yet been supplied, 0 should be returned indicating an
146 error.
147 "key" (OSSL_KDF_PARAM_KEY) <octet string>
149 Sets the key in the associated KDF ctx.
150 "secret" (OSSL_KDF_PARAM_SECRET) <octet string>
152 Sets the secret in the associated KDF ctx.
153 "pass" (OSSL_KDF_PARAM_PASSWORD) <octet string>
155 Sets the password in the associated KDF ctx.
156 "cipher" (OSSL_KDF_PARAM_CIPHER) <UTF8 string>
158 "digest" (OSSL_KDF_PARAM_DIGEST) <UTF8 string>
159 "mac" (OSSL_KDF_PARAM_MAC) <UTF8 string>
160 Sets the name of the underlying cipher, digest or MAC to be used.
161 It must name a suitable algorithm for the KDF that's being used.
162 "maclen" (OSSL_KDF_PARAM_MAC_SIZE) <octet string>
164 Sets the length of the MAC in the associated KDF ctx.
165 "properties" (OSSL_KDF_PARAM_PROPERTIES) <UTF8 string>
167 Sets the properties to be queried when trying to fetch the
168 underlying algorithm. This must be given together with the
169 algorithm naming parameter to be considered valid.
170 "iter" (OSSL_KDF_PARAM_ITER) <unsigned integer>
172 Sets the number of iterations in the associated KDF ctx.
173 "mode" (OSSL_KDF_PARAM_MODE) <UTF8 string>
175 Sets the mode in the associated KDF ctx.
176 "pkcs5" (OSSL_KDF_PARAM_PKCS5) <integer>
178 Enables or diables the SP800-132 compliance checks. A mode of 0
179 enables the compliance checks.
180 The checks performed are:
182 - the iteration count is at least 1000.
184 - the salt length is at least 128 bits.
185 - the derived key length is at least 112 bits.
186 "ukm" (OSSL_KDF_PARAM_UKM) <octet string>
187 Sets an optional random string that is provided by the sender
188 called "partyAInfo". In CMS this is the user keying material.
189 "cekalg" (OSSL_KDF_PARAM_CEK_ALG) <UTF8 string>
191 Sets the CEK wrapping algorithm name in the associated KDF ctx.
192 "n" (OSSL_KDF_PARAM_SCRYPT_N) <unsigned integer>
194 Sets the scrypt work factor parameter N in the associated KDF ctx.
195 "r" (OSSL_KDF_PARAM_SCRYPT_R) <unsigned integer>
197 Sets the scrypt work factor parameter r in the associated KDF ctx.
198 "p" (OSSL_KDF_PARAM_SCRYPT_P) <unsigned integer>
200 Sets the scrypt work factor parameter p in the associated KDF ctx.
201 "maxmem_bytes" (OSSL_KDF_PARAM_SCRYPT_MAXMEM) <unsigned integer>
203 Sets the scrypt work factor parameter maxmem in the associated KDF
204 ctx.
205 "prefix" (OSSL_KDF_PARAM_PREFIX) <octet string>
207 Sets the prefix string using by the TLS 1.3 version of HKDF in the
208 associated KDF ctx.
209 "label" (OSSL_KDF_PARAM_LABEL) <octet string>
211 Sets the label string using by the TLS 1.3 version of HKDF in the
212 associated KDF ctx.
213 "data" (OSSL_KDF_PARAM_DATA) <octet string>
215 Sets the context string using by the TLS 1.3 version of HKDF in the
216 associated KDF ctx.
217 "info" (OSSL_KDF_PARAM_INFO) <octet string>
219 Sets the optional shared info in the associated KDF ctx.
220 "seed" (OSSL_KDF_PARAM_SEED) <octet string>
222 Sets the IV in the associated KDF ctx.
223 "xcghash" (OSSL_KDF_PARAM_SSHKDF_XCGHASH) <octet string>
225 Sets the xcghash in the associated KDF ctx.
226 "session_id" (OSSL_KDF_PARAM_SSHKDF_SESSION_ID) <octet string>
228 Sets the session ID in the associated KDF ctx.
229 "type" (OSSL_KDF_PARAM_SSHKDF_TYPE) <UTF8 string>
231 Sets the SSH KDF type parameter in the associated KDF ctx. There
232 are six supported types:
233 EVP_KDF_SSHKDF_TYPE_INITIAL_IV_CLI_TO_SRV
235 The Initial IV from client to server. A single char of value
236 65 (ASCII char 'A').
237 EVP_KDF_SSHKDF_TYPE_INITIAL_IV_SRV_TO_CLI
239 The Initial IV from server to client A single char of value 66
240 (ASCII char 'B').
241 EVP_KDF_SSHKDF_TYPE_ENCRYPTION_KEY_CLI_TO_SRV
243 The Encryption Key from client to server A single char of value
244 67 (ASCII char 'C').
245 EVP_KDF_SSHKDF_TYPE_ENCRYPTION_KEY_SRV_TO_CLI
247 The Encryption Key from server to client A single char of value
248 68 (ASCII char 'D').
249 EVP_KDF_SSHKDF_TYPE_INTEGRITY_KEY_CLI_TO_SRV
251 The Integrity Key from client to server A single char of value
252 69 (ASCII char 'E').
253 EVP_KDF_SSHKDF_TYPE_INTEGRITY_KEY_SRV_TO_CLI
255 The Integrity Key from client to server A single char of value
256 70 (ASCII char 'F').
257 "constant" (OSSL_KDF_PARAM_CONSTANT) <octet string>
259 Sets the constant value in the associated KDF ctx.
260 "id" (OSSL_KDF_PARAM_PKCS12_ID) <integer>
262 Sets the intended usage of the output bits in the associated KDF
263 ctx. It is defined as per RFC 7292 section B.3.
264
266 OSSL_FUNC_kdf_newctx() and OSSL_FUNC_kdf_dupctx() should return the
267 newly created provider side KDF context, or NULL on failure.
268 OSSL_FUNC_kdf_derive(), OSSL_FUNC_kdf_get_params(),
270 OSSL_FUNC_kdf_get_ctx_params() and OSSL_FUNC_kdf_set_ctx_params()
271 should return 1 for success or 0 on error.
272 OSSL_FUNC_kdf_gettable_params(), OSSL_FUNC_kdf_gettable_ctx_params()
274 and OSSL_FUNC_kdf_settable_ctx_params() should return a constant
275 OSSL_PARAM(3) array, or NULL if none is offered.
276
278 The KDF life-cycle is described in life_cycle-kdf(7). Providers should
279 ensure that the various transitions listed there are supported. At
280 some point the EVP layer will begin enforcing the listed transitions.
281
283 provider(7), life_cycle-kdf(7), EVP_KDF(3).
284
286 The provider KDF interface was introduced in OpenSSL 3.0.
287
289 Copyright 2020-2022 The OpenSSL Project Authors. All Rights Reserved.
290 Licensed under the Apache License 2.0 (the "License"). You may not use
292 this file except in compliance with the License. You can obtain a copy
293 in the file LICENSE in the source distribution or at
294 <https://www.openssl.org/source/license.html>.
2953.0.9 2023-07-27 PROVIDER-KDF(7ossl)