5 provider-keymgmt - The KEYMGMT library E<lt>-E<gt> provider functions
9 #include <openssl/core_numbers.h>
12 * None of these are actual functions, but are displayed like this for
13 * the function signatures for functions that are offered as function
14 * pointers in OSSL_DISPATCH arrays.
17 /* Key object (keydata) creation and destruction */
18 void *OP_keymgmt_new(void *provctx);
19 void OP_keymgmt_free(void *keydata);
21 /* Key object information */
22 int OP_keymgmt_get_params(void *keydata, OSSL_PARAM params[]);
23 const OSSL_PARAM *OP_keymgmt_gettable_params(void);
24 int OP_keymgmt_set_params(void *keydata, const OSSL_PARAM params[]);
25 const OSSL_PARAM *OP_keymgmt_settable_params(void);
27 /* Key object content checks */
28 int OP_keymgmt_has(void *keydata, int selection);
29 int OP_keymgmt_match(const void *keydata1, const void *keydata2,
32 /* Discovery of supported operations */
33 const char *OP_keymgmt_query_operation_name(int operation_id);
35 /* Key object import and export functions */
36 int OP_keymgmt_import(int selection, void *keydata, const OSSL_PARAM params[]);
37 const OSSL_PARAM *OP_keymgmt_import_types(int selection);
38 int OP_keymgmt_export(int selection, void *keydata,
39 OSSL_CALLBACK *param_cb, void *cbarg);
40 const OSSL_PARAM *OP_keymgmt_export_types(int selection);
43 int OP_keymgmt_copy(void *keydata_to, const void *keydata_from, int selection);
45 /* Key object validation */
46 int OP_keymgmt_validate(void *keydata, int selection);
50 The KEYMGMT operation doesn't have much public visibility in OpenSSL
51 libraries, it's rather an internal operation that's designed to work
52 in tandem with operations that use private/public key pairs.
54 Because the KEYMGMT operation shares knowledge with the operations it
55 works with in tandem, they must belong to the same provider.
56 The OpenSSL libraries will ensure that they do.
58 The primary responsibility of the KEYMGMT operation is to hold the
59 provider side key data for the OpenSSL library EVP_PKEY structure.
61 All "functions" mentioned here are passed as function pointers between
62 F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays via
63 B<OSSL_ALGORITHM> arrays that are returned by the provider's
64 provider_query_operation() function
65 (see L<provider-base(7)/Provider Functions>).
67 All these "functions" have a corresponding function type definition
68 named B<OSSL_{name}_fn>, and a helper function to retrieve the
69 function pointer from a B<OSSL_DISPATCH> element named
71 For example, the "function" OP_keymgmt_new() has these:
73 typedef void *(OSSL_OP_keymgmt_new_fn)(void *provctx);
74 static ossl_inline OSSL_OP_keymgmt_new_fn
75 OSSL_get_OP_keymgmt_new(const OSSL_DISPATCH *opf);
77 B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
78 macros in L<openssl-core_numbers.h(7)>, as follows:
80 OP_keymgmt_new OSSL_FUNC_KEYMGMT_NEW
81 OP_keymgmt_free OSSL_FUNC_KEYMGMT_FREE
83 OP_keymgmt_get_params OSSL_FUNC_KEYMGMT_GET_PARAMS
84 OP_keymgmt_gettable_params OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS
85 OP_keymgmt_set_params OSSL_FUNC_KEYMGMT_SET_PARAMS
86 OP_keymgmt_settable_params OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS
88 OP_keymgmt_query_operation_name OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME
90 OP_keymgmt_has OSSL_FUNC_KEYMGMT_HAS
91 OP_keymgmt_validate OSSL_FUNC_KEYMGMT_VALIDATE
92 OP_keymgmt_match OSSL_FUNC_KEYMGMT_MATCH
94 OP_keymgmt_import OSSL_FUNC_KEYMGMT_IMPORT
95 OP_keymgmt_import_types OSSL_FUNC_KEYMGMT_IMPORT_TYPES
96 OP_keymgmt_export OSSL_FUNC_KEYMGMT_EXPORT
97 OP_keymgmt_export_types OSSL_FUNC_KEYMGMT_EXPORT_TYPES
99 OP_keymgmt_copy OSSL_FUNC_KEYMGMT_COPY
103 A key object is a collection of data for an asymmetric key, and is
104 represented as I<keydata> in this manual.
106 The exact contents of a key object are defined by the provider, and it
107 is assumed that different operations in one and the same provider use
108 the exact same structure to represent this collection of data, so that
109 for example, a key object that has been created using the KEYMGMT
110 interface that we document here can be passed as is to other provider
111 operations, such as OP_signature_sign_init() (see
112 L<provider-signature(7)>).
114 With some of the KEYMGMT functions, it's possible to select a specific
115 subset of data to handle, governed by the bits in a I<selection>
116 indicator. The bits are:
120 =item B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY>
122 Indicating that the private key data in a key object should be
125 =item B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY>
127 Indicating that the public key data in a key object should be
130 =item B<OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS>
132 Indicating that the domain parameters in a key object should be
135 =item B<OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS>
137 Indicating that other parameters in a key object should be
140 Other parameters are key parameters that don't fit any other
141 classification. In other words, this particular selector bit works as
142 a last resort bit bucket selector.
146 Some selector bits have also been combined for easier use:
150 =item B<OSSL_KEYMGMT_SELECT_ALL_PARAMETERS>
152 Indicating that all key object parameters should be considered,
153 regardless of their more granular classification.
155 =for comment This should used by EVP functions such as
156 EVP_PKEY_copy_parameters() and EVP_PKEY_cmp_parameters()
158 This is a combination of B<OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS> and
159 B<OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS>.
161 =for comment If more parameter categories are added, they should be
164 =item B<OSSL_KEYMGMT_SELECT_KEYPAIR>
166 Indicating that both the whole key pair in a key object should be
167 considered, i.e. the combination of public and private key.
169 This is a combination of B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY> and
170 B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY>.
172 =item B<OSSL_KEYMGMT_SELECT_ALL>
174 Indicating that everything in a key object should be considered.
178 The exact interpretation of those bits or how they combine is left to
179 each function where you can specify a selector.
181 =for comment One might think that a combination of bits means that all
182 the selected data subsets must be considered, but then you have to
183 consider that when comparing key objects (future function), an
184 implementation might opt to not compare the private key if it has
185 compared the public key, since a match of one half implies a match of
188 =head2 Constructing and Destructing Functions
190 OP_keymgmt_new() should create a provider side key object. The
191 provider context I<provctx> is passed and may be incorporated in the
192 key object, but that is not mandatory.
194 OP_keymgmt_free() should free the passed I<keydata>.
196 The constructor and destructor are mandatory, a KEYMGMT implementation
197 without them will not be accepted.
199 =for comment when new constructors appear, it's sufficient if only one
200 of them is present. The remark above will have to change to reflect
203 =head2 Key Object Information Functions
205 OP_keymgmt_get_params() should extract information data associated
206 with the given I<keydata>, see L</Information Parameters>.
208 OP_keymgmt_gettable_params() should return a constant array of
209 descriptor B<OSSL_PARAM>, for parameters that OP_keymgmt_get_params()
212 If OP_keymgmt_gettable_params() is present, OP_keymgmt_get_params()
213 must also be present, and vice versa.
215 OP_keymgmt_set_params() should update information data associated
216 with the given I<keydata>, see L</Information Parameters>.
218 OP_keymgmt_settable_params() should return a constant array of
219 descriptor B<OSSL_PARAM>, for parameters that OP_keymgmt_set_params()
222 If OP_keymgmt_settable_params() is present, OP_keymgmt_set_params()
223 must also be present, and vice versa.
225 =head2 Key Object Checking Functions
227 OP_keymgmt_query_operation_name() should return the name of the
228 supported algorithm for the operation I<operation_id>. This is
229 similar to provider_query_operation() (see L<provider-base(7)>),
230 but only works as an advisory. If this function is not present, or
231 returns NULL, the caller is free to assume that there's an algorithm
232 from the same provider, of the same name as the one used to fetch the
233 keymgmt and try to use that.
235 OP_keymgmt_has() should check whether the given I<keydata> contains the subsets
236 of data indicated by the I<selector>. A combination of several
237 selector bits must consider all those subsets, not just one. An
238 implementation is, however, free to consider an empty subset of data
239 to still be a valid subset.
241 OP_keymgmt_validate() should check if the I<keydata> contains valid
242 data subsets indicated by I<selection>. Some combined selections of
243 data subsets may cause validation of the combined data.
244 For example, the combination of B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY> and
245 B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY> (or B<OSSL_KEYMGMT_SELECT_KEYPAIR>
246 for short) is expected to check that the pairwise consistency of
249 OP_keymgmt_match() should check if the data subset indicated by
250 I<selection> in I<keydata1> and I<keydata2> match. It is assumed that
251 the caller has ensured that I<keydata1> and I<keydata2> are both owned
252 by the implementation of this function.
254 =head2 Key Object Import, Export and Copy Functions
256 OP_keymgmt_import() should import data indicated by I<selection> into
257 I<keydata> with values taken from the B<OSSL_PARAM> array I<params>.
259 OP_keymgmt_export() should extract values indicated by I<selection>
260 from I<keydata>, create an B<OSSL_PARAM> array with them and call
261 I<param_cb> with that array as well as the given I<cbarg>.
263 OP_keymgmt_import_types() should return a constant array of descriptor
264 B<OSSL_PARAM> for data indicated by I<selection>, for parameters that
265 OP_keymgmt_import() can handle.
267 OP_keymgmt_export_types() should return a constant array of descriptor
268 B<OSSL_PARAM> for data indicated by I<selection>, that the
269 OP_keymgmt_export() callback can expect to receive.
271 OP_keymgmt_copy() should copy data subsets indicated by I<selection>
272 from I<keydata_from> to I<keydata_to>. It is assumed that the caller
273 has ensured that I<keydata_to> and I<keydata_from> are both owned by
274 the implementation of this function.
276 =head2 Built-in RSA Import/Export Types
278 The following Import/Export types are available for the built-in RSA algorithm:
282 =item "n" (B<OSSL_PKEY_PARAM_RSA_N>) <unsigned integer>
286 =item "e" (B<OSSL_PKEY_PARAM_RSA_E>) <unsigned integer>
290 =item "d" (B<OSSL_PKEY_PARAM_RSA_D>) <unsigned integer>
294 =item "rsa-factor" (B<OSSL_PKEY_PARAM_RSA_FACTOR>) <unsigned integer>
296 An RSA factor. In 2 prime RSA these are often known as "p" or "q". This value
297 may be repeated up to 10 times in a single key.
299 =item "rsa-exponent" (B<OSSL_PKEY_PARAM_RSA_EXPONENT>) <unsigned integer>
301 An RSA CRT (Chinese Remainder Theorem) exponent. This value may be repeated up
302 to 10 times in a single key.
304 =item "rsa-coefficient" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT>) <unsigned integer>
306 An RSA CRT (Chinese Remainder Theorem) coefficient. This value may be repeated
307 up to 9 times in a single key.
311 =head2 Built-in DSA and Diffie-Hellman Import/Export Types
313 The following Import/Export types are available for the built-in DSA and
314 Diffie-Hellman algorithms:
318 =item "pub" (B<OSSL_PKEY_PARAM_PUB_KEY>) <unsigned integer>
320 The public key value.
322 =item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <unsigned integer>
324 The private key value.
326 =item "p" (B<OSSL_PKEY_PARAM_FFC_P>) <unsigned integer>
328 A DSA or Diffie-Hellman "p" value.
330 =item "q" (B<OSSL_PKEY_PARAM_FFC_Q>) <unsigned integer>
332 A DSA or Diffie-Hellman "q" value.
334 =item "g" (B<OSSL_PKEY_PARAM_FFC_G>) <unsigned integer>
336 A DSA or Diffie-Hellman "g" value.
340 =head2 Built-in X25519, X448, ED25519 and ED448 Import/Export Types
342 The following Import/Export types are available for the built-in X25519, X448,
343 ED25519 and X448 algorithms:
347 =item "pub" (B<OSSL_PKEY_PARAM_PUB_KEY>) <octet string>
349 The public key value.
351 =item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <octet string>
353 The private key value.
357 =head2 Built-in EC Import/Export Types
359 The following Import/Export types are available for the built-in EC algorithm:
363 =item "curve-name" (B<OSSL_PKEY_PARAM_EC_NAME>) <utf8 string>
367 =item "use-cofactor-flag" (B<OSSL_PKEY_PARAM_USE_COFACTOR_ECDH>) <integer>
369 Enable Cofactor DH (ECC CDH) if this value is 1, otherwise it uses normal EC DH
370 if the value is zero. The cofactor variant multiplies the shared secret by the
371 EC curve's cofactor (note for some curves the cofactor is 1).
373 =item "pub" (B<OSSL_PKEY_PARAM_PUB_KEY>) <octet string>
375 The public key value in EC point format.
377 =item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <unsigned integer>
379 The private key value.
383 =head2 Information Parameters
385 See L<OSSL_PARAM(3)> for further details on the parameters structure.
387 Parameters currently recognised by built-in keymgmt algorithms
389 Not all parameters are relevant to, or are understood by all keymgmt
394 =item "bits" (B<OSSL_PKEY_PARAM_BITS>) <integer>
396 The value should be the cryptographic length of the cryptosystem to
397 which the key belongs, in bits. The definition of cryptographic
398 length is specific to the key cryptosystem.
400 =item "max-size" (B<OSSL_PKEY_PARAM_MAX_SIZE>) <integer>
402 The value should be the maximum size that a caller should allocate to
403 safely store a signature (called I<sig> in L<provider-signature(7)>),
404 the result of asymmmetric encryption / decryption (I<out> in
405 L<provider-asym_cipher(7)>, a derived secret (I<secret> in
406 L<provider-keyexch(7)>, and similar data).
408 Because an EVP_KEYMGMT method is always tightly bound to another method
409 (signature, asymmetric cipher, key exchange, ...) and must be of the
410 same provider, this number only needs to be synchronised with the
411 dimensions handled in the rest of the same provider.
413 =item "security-bits" (B<OSSL_PKEY_PARAM_SECURITY_BITS>) <integer>
415 The value should be the number of security bits of the given key.
416 Bits of security is defined in SP800-57.
418 =item "use-cofactor-flag" (B<OSSL_PKEY_PARAM_USE_COFACTOR_FLAG>,
419 B<OSSL_PKEY_PARAM_USE_COFACTOR_ECDH>) <integer>
421 The value should be either 1 or 0, to respectively enable or disable
422 use of the cofactor in operations using this key.
424 In the context of a key that can be used to perform an Elliptic Curve
425 Diffie-Hellman key exchange, this parameter can be used to mark a requirement
426 for using the Cofactor Diffie-Hellman (CDH) variant of the key exchange
429 See also L<provider-keyexch(7)> for the related
430 B<OSSL_EXCHANGE_PARAM_EC_ECDH_COFACTOR_MODE> parameter that can be set on a
437 OP_keymgmt_new() should return a valid reference to the newly created provider
438 side key object, or NULL on failure.
440 OP_keymgmt_import(), OP_keymgmt_export(), OP_keymgmt_get_params() and
441 OP_keymgmt_set_params() should return 1 for success or 0 on error.
443 OP_keymgmt_validate() should return 1 on successful validation, or 0 on
446 OP_keymgmt_has() should return 1 if all the selected data subsets are contained
447 in the given I<keydata> or 0 otherwise.
449 OP_keymgmt_query_operation_name() should return a pointer to a string matching
450 the requested operation, or NULL if the same name used to fetch the keymgmt
453 OP_keymgmt_gettable_params() and OP_keymgmt_settable_params()
454 OP_keymgmt_import_types(), OP_keymgmt_export_types()
456 always return a constant B<OSSL_PARAM> array.
464 The KEYMGMT interface was introduced in OpenSSL 3.0.
468 Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
470 Licensed under the Apache License 2.0 (the "License"). You may not use
471 this file except in compliance with the License. You can obtain a copy
472 in the file LICENSE in the source distribution or at
473 L<https://www.openssl.org/source/license.html>.