]> git.ipfire.org Git - thirdparty/openssl.git/blame_incremental - doc/man7/provider-keymgmt.pod
Add DSA keygen to provider
[thirdparty/openssl.git] / doc / man7 / provider-keymgmt.pod
... / ...
CommitLineData
1=pod
2
3=head1 NAME
4
5provider-keymgmt - The KEYMGMT library E<lt>-E<gt> provider functions
6
7=head1 SYNOPSIS
8
9 #include <openssl/core_numbers.h>
10
11 /*
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.
15 */
16
17 /* Key object (keydata) creation and destruction */
18 void *OP_keymgmt_new(void *provctx);
19 void OP_keymgmt_free(void *keydata);
20
21 void *OP_keymgmt_gen_init(void *provctx, int selection);
22 int OP_keymgmt_gen_set_template(void *genctx, void *template);
23 int OP_keymgmt_gen_set_params(void *genctx, const OSSL_PARAM params[]);
24 const OSSL_PARAM *OP_keymgmt_gen_settable_params(void *provctx);
25 int OP_keymgmt_gen_get_params(void *genctx, const OSSL_PARAM params[]);
26 const OSSL_PARAM *OP_keymgmt_gen_gettable_params(void *provctx);
27 void *OP_keymgmt_gen(void *genctx, OSSL_CALLBACK *cb, void *cbarg);
28 void OP_keymgmt_gen_cleanup(void *genctx);
29
30 /* Key object information */
31 int OP_keymgmt_get_params(void *keydata, OSSL_PARAM params[]);
32 const OSSL_PARAM *OP_keymgmt_gettable_params(void);
33 int OP_keymgmt_set_params(void *keydata, const OSSL_PARAM params[]);
34 const OSSL_PARAM *OP_keymgmt_settable_params(void);
35
36 /* Key object content checks */
37 int OP_keymgmt_has(void *keydata, int selection);
38 int OP_keymgmt_match(const void *keydata1, const void *keydata2,
39 int selection);
40
41 /* Discovery of supported operations */
42 const char *OP_keymgmt_query_operation_name(int operation_id);
43
44 /* Key object import and export functions */
45 int OP_keymgmt_import(int selection, void *keydata, const OSSL_PARAM params[]);
46 const OSSL_PARAM *OP_keymgmt_import_types(int selection);
47 int OP_keymgmt_export(int selection, void *keydata,
48 OSSL_CALLBACK *param_cb, void *cbarg);
49 const OSSL_PARAM *OP_keymgmt_export_types(int selection);
50
51 /* Key object copy */
52 int OP_keymgmt_copy(void *keydata_to, const void *keydata_from, int selection);
53
54 /* Key object validation */
55 int OP_keymgmt_validate(void *keydata, int selection);
56
57=head1 DESCRIPTION
58
59The KEYMGMT operation doesn't have much public visibility in OpenSSL
60libraries, it's rather an internal operation that's designed to work
61in tandem with operations that use private/public key pairs.
62
63Because the KEYMGMT operation shares knowledge with the operations it
64works with in tandem, they must belong to the same provider.
65The OpenSSL libraries will ensure that they do.
66
67The primary responsibility of the KEYMGMT operation is to hold the
68provider side key data for the OpenSSL library EVP_PKEY structure.
69
70All "functions" mentioned here are passed as function pointers between
71F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays via
72B<OSSL_ALGORITHM> arrays that are returned by the provider's
73provider_query_operation() function
74(see L<provider-base(7)/Provider Functions>).
75
76All these "functions" have a corresponding function type definition
77named B<OSSL_{name}_fn>, and a helper function to retrieve the
78function pointer from a B<OSSL_DISPATCH> element named
79B<OSSL_get_{name}>.
80For example, the "function" OP_keymgmt_new() has these:
81
82 typedef void *(OSSL_OP_keymgmt_new_fn)(void *provctx);
83 static ossl_inline OSSL_OP_keymgmt_new_fn
84 OSSL_get_OP_keymgmt_new(const OSSL_DISPATCH *opf);
85
86B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
87macros in L<openssl-core_numbers.h(7)>, as follows:
88
89 OP_keymgmt_new OSSL_FUNC_KEYMGMT_NEW
90 OP_keymgmt_free OSSL_FUNC_KEYMGMT_FREE
91
92 OP_keymgmt_gen_init OSSL_FUNC_KEYMGMT_GEN_INIT
93 OP_keymgmt_gen_set_template OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE
94 OP_keymgmt_gen_set_params OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS
95 OP_keymgmt_gen_settable_params OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS
96 OP_keymgmt_gen_get_params OSSL_FUNC_KEYMGMT_GEN_GET_PARAMS
97 OP_keymgmt_gen_gettable_params OSSL_FUNC_KEYMGMT_GEN_GETTABLE_PARAMS
98 OP_keymgmt_gen OSSL_FUNC_KEYMGMT_GEN
99 OP_keymgmt_gen_cleanup OSSL_FUNC_KEYMGMT_GEN_CLEANUP
100
101 OP_keymgmt_get_params OSSL_FUNC_KEYMGMT_GET_PARAMS
102 OP_keymgmt_gettable_params OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS
103 OP_keymgmt_set_params OSSL_FUNC_KEYMGMT_SET_PARAMS
104 OP_keymgmt_settable_params OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS
105
106 OP_keymgmt_query_operation_name OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME
107
108 OP_keymgmt_has OSSL_FUNC_KEYMGMT_HAS
109 OP_keymgmt_validate OSSL_FUNC_KEYMGMT_VALIDATE
110 OP_keymgmt_match OSSL_FUNC_KEYMGMT_MATCH
111
112 OP_keymgmt_import OSSL_FUNC_KEYMGMT_IMPORT
113 OP_keymgmt_import_types OSSL_FUNC_KEYMGMT_IMPORT_TYPES
114 OP_keymgmt_export OSSL_FUNC_KEYMGMT_EXPORT
115 OP_keymgmt_export_types OSSL_FUNC_KEYMGMT_EXPORT_TYPES
116
117 OP_keymgmt_copy OSSL_FUNC_KEYMGMT_COPY
118
119=head2 Key Objects
120
121A key object is a collection of data for an asymmetric key, and is
122represented as I<keydata> in this manual.
123
124The exact contents of a key object are defined by the provider, and it
125is assumed that different operations in one and the same provider use
126the exact same structure to represent this collection of data, so that
127for example, a key object that has been created using the KEYMGMT
128interface that we document here can be passed as is to other provider
129operations, such as OP_signature_sign_init() (see
130L<provider-signature(7)>).
131
132With some of the KEYMGMT functions, it's possible to select a specific
133subset of data to handle, governed by the bits in a I<selection>
134indicator. The bits are:
135
136=over 4
137
138=item B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY>
139
140Indicating that the private key data in a key object should be
141considered.
142
143=item B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY>
144
145Indicating that the public key data in a key object should be
146considered.
147
148=item B<OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS>
149
150Indicating that the domain parameters in a key object should be
151considered.
152
153=item B<OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS>
154
155Indicating that other parameters in a key object should be
156considered.
157
158Other parameters are key parameters that don't fit any other
159classification. In other words, this particular selector bit works as
160a last resort bit bucket selector.
161
162=back
163
164Some selector bits have also been combined for easier use:
165
166=over 4
167
168=item B<OSSL_KEYMGMT_SELECT_ALL_PARAMETERS>
169
170Indicating that all key object parameters should be considered,
171regardless of their more granular classification.
172
173=for comment This should used by EVP functions such as
174EVP_PKEY_copy_parameters() and EVP_PKEY_cmp_parameters()
175
176This is a combination of B<OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS> and
177B<OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS>.
178
179=for comment If more parameter categories are added, they should be
180mentioned here too.
181
182=item B<OSSL_KEYMGMT_SELECT_KEYPAIR>
183
184Indicating that both the whole key pair in a key object should be
185considered, i.e. the combination of public and private key.
186
187This is a combination of B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY> and
188B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY>.
189
190=item B<OSSL_KEYMGMT_SELECT_ALL>
191
192Indicating that everything in a key object should be considered.
193
194=back
195
196The exact interpretation of those bits or how they combine is left to
197each function where you can specify a selector.
198
199=for comment One might think that a combination of bits means that all
200the selected data subsets must be considered, but then you have to
201consider that when comparing key objects (future function), an
202implementation might opt to not compare the private key if it has
203compared the public key, since a match of one half implies a match of
204the other half.
205
206=head2 Constructing and Destructing Functions
207
208OP_keymgmt_new() should create a provider side key object. The
209provider context I<provctx> is passed and may be incorporated in the
210key object, but that is not mandatory.
211
212OP_keymgmt_free() should free the passed I<keydata>.
213
214OP_keymgmt_gen_init(), OP_keymgmt_gen_set_template(),
215OP_keymgmt_gen_set_params(), OP_keymgmt_gen_settable_params(),
216OP_keymgmt_gen_get_params(), OP_keymgmt_gen_gettable_params(),
217OP_keymgmt_gen() and OP_keymgmt_gen_cleanup() work together as a more
218elaborate context based key object constructor.
219
220OP_keymgmt_gen_init() should create the key object generation context
221and initialize it with I<selections>, which will determine what kind
222of contents the key object to be generated should get.
223
224OP_keymgmt_gen_set_template() should add I<template> to the context
225I<genctx>. The I<template> is assumed to be a key object constructed
226with the same KEYMGMT, and from which content that the implementation
227chooses can be used as a template for the key object to be generated.
228Typically, the generation of a DSA or DH key would get the domain
229parameters from this I<template>.
230
231OP_keymgmt_gen_set_params() should set additional parameters from
232I<params> in the key object generation context I<genctx>.
233
234OP_keymgmt_gen_settable_params() should return a constant array of
235descriptor B<OSSL_PARAM>, for parameters that OP_keymgmt_gen_set_params()
236can handle.
237
238OP_keymgmt_gen_get_params() should extract information data associated
239with the key object generation context I<genctx>.
240
241OP_keymgmt_gen_gettable_params() should return a constant array of
242descriptor B<OSSL_PARAM>, for parameters that OP_keymgmt_gen_get_params()
243can handle.
244
245OP_keymgmt_gen() should perform the key object generation itself, and
246return the result. The callback I<cb> should be called at regular
247intervals with indications on how the key object generation
248progresses.
249
250OP_keymgmt_gen_cleanup() should clean up and free the key object
251generation context I<genctx>
252
253At least one of OP_keymgmt_new() and OP_keymgmt_gen() are mandatory,
254as well as OP_keymgmt_free(). Additionally, if OP_keymgmt_gen() is
255present, OP_keymgmt_gen_init() and OP_keymgmt_gen_cleanup() must be
256present as well.
257
258=head2 Key Object Information Functions
259
260OP_keymgmt_get_params() should extract information data associated
261with the given I<keydata>, see L</Information Parameters>.
262
263OP_keymgmt_gettable_params() should return a constant array of
264descriptor B<OSSL_PARAM>, for parameters that OP_keymgmt_get_params()
265can handle.
266
267If OP_keymgmt_gettable_params() is present, OP_keymgmt_get_params()
268must also be present, and vice versa.
269
270OP_keymgmt_set_params() should update information data associated
271with the given I<keydata>, see L</Information Parameters>.
272
273OP_keymgmt_settable_params() should return a constant array of
274descriptor B<OSSL_PARAM>, for parameters that OP_keymgmt_set_params()
275can handle.
276
277If OP_keymgmt_settable_params() is present, OP_keymgmt_set_params()
278must also be present, and vice versa.
279
280=head2 Key Object Checking Functions
281
282OP_keymgmt_query_operation_name() should return the name of the
283supported algorithm for the operation I<operation_id>. This is
284similar to provider_query_operation() (see L<provider-base(7)>),
285but only works as an advisory. If this function is not present, or
286returns NULL, the caller is free to assume that there's an algorithm
287from the same provider, of the same name as the one used to fetch the
288keymgmt and try to use that.
289
290OP_keymgmt_has() should check whether the given I<keydata> contains the subsets
291of data indicated by the I<selector>. A combination of several
292selector bits must consider all those subsets, not just one. An
293implementation is, however, free to consider an empty subset of data
294to still be a valid subset.
295
296OP_keymgmt_validate() should check if the I<keydata> contains valid
297data subsets indicated by I<selection>. Some combined selections of
298data subsets may cause validation of the combined data.
299For example, the combination of B<OSSL_KEYMGMT_SELECT_PRIVATE_KEY> and
300B<OSSL_KEYMGMT_SELECT_PUBLIC_KEY> (or B<OSSL_KEYMGMT_SELECT_KEYPAIR>
301for short) is expected to check that the pairwise consistency of
302I<keydata> is valid.
303
304OP_keymgmt_match() should check if the data subset indicated by
305I<selection> in I<keydata1> and I<keydata2> match. It is assumed that
306the caller has ensured that I<keydata1> and I<keydata2> are both owned
307by the implementation of this function.
308
309=head2 Key Object Import, Export and Copy Functions
310
311OP_keymgmt_import() should import data indicated by I<selection> into
312I<keydata> with values taken from the B<OSSL_PARAM> array I<params>.
313
314OP_keymgmt_export() should extract values indicated by I<selection>
315from I<keydata>, create an B<OSSL_PARAM> array with them and call
316I<param_cb> with that array as well as the given I<cbarg>.
317
318OP_keymgmt_import_types() should return a constant array of descriptor
319B<OSSL_PARAM> for data indicated by I<selection>, for parameters that
320OP_keymgmt_import() can handle.
321
322OP_keymgmt_export_types() should return a constant array of descriptor
323B<OSSL_PARAM> for data indicated by I<selection>, that the
324OP_keymgmt_export() callback can expect to receive.
325
326OP_keymgmt_copy() should copy data subsets indicated by I<selection>
327from I<keydata_from> to I<keydata_to>. It is assumed that the caller
328has ensured that I<keydata_to> and I<keydata_from> are both owned by
329the implementation of this function.
330
331=head2 Built-in DSA Key Generation Types
332
333The following Key Generation types are available for the built-in DSA algorithm:
334
335=over 4
336
337=item "pbits" (B<OSSL_PKEY_PARAM_FFC_PBITS>) <unsigned integer>
338
339Sets the DSA size (in bits) of the prime 'p'.
340The value should be 2048 or 3072.
341
342=item "qbits" (B<OSSL_PKEY_PARAM_FFC_QBITS>) <unsigned integer>
343
344Sets the DSA size (in bits) of the prime 'q'.
345The value should be 224 or 256.
346
347=item "type" (B<OSSL_PKEY_PARAM_FFC_TYPE>) <integer>
348
349Sets the type of parameter generation.
350Use 0 for FIPS186-4, or 1 for legacy FIPS186-2.
351The default is 0.
352
353=item "digest" (B<OSSL_PKEY_PARAM_FFC_DIGEST>) <utf8_string>
354
355Sets the Digest algorithm to be used as part of the Key Generation Function
356associated with the given Key Generation I<ctx>.
357
358=item "properties" (B<OSSL_PKEY_PARAM_FFC_DIGEST_PROPS>) <utf8_string>
359
360Sets properties to be used upon look up of the implementation for the selected
361Digest algorithm for the Key Generation Function associated with the given key
362Generation I<ctx>.
363
364=item "gindex" (B<OSSL_PKEY_PARAM_FFC_GINDEX>) <integer>
365
366Sets the index to use for canonical generation and verification of the generator g.
367Set this to a positive value to use this mode. This I<index> can then be reused
368during key validation to verify the value of g. If this value is not set then
369g is not verifiable. The default value is -1.
370
371=item "seed" (B<OSSL_PKEY_PARAM_FFC_SEED>) <octet_string>
372
373Sets the I<seed> data to use instead of generating a random seed internally.
374This should be used for testing purposes only. This will either produced fixed
375values for the generated parameters OR it will fail if the seed did not
376generate valid primes.
377
378=back
379
380
381=head2 Built-in RSA Import/Export Types
382
383The following Import/Export types are available for the built-in RSA algorithm:
384
385=over 4
386
387=item "n" (B<OSSL_PKEY_PARAM_RSA_N>) <unsigned integer>
388
389The RSA "n" value.
390
391=item "e" (B<OSSL_PKEY_PARAM_RSA_E>) <unsigned integer>
392
393The RSA "e" value.
394
395=item "d" (B<OSSL_PKEY_PARAM_RSA_D>) <unsigned integer>
396
397The RSA "d" value.
398
399=item "rsa-factor1" (B<OSSL_PKEY_PARAM_RSA_FACTOR1>) <unsigned integer>
400
401=item "rsa-factor2" (B<OSSL_PKEY_PARAM_RSA_FACTOR2>) <unsigned integer>
402
403=item "rsa-factor3" (B<OSSL_PKEY_PARAM_RSA_FACTOR3>) <unsigned integer>
404
405=item "rsa-factor4" (B<OSSL_PKEY_PARAM_RSA_FACTOR4>) <unsigned integer>
406
407=item "rsa-factor5" (B<OSSL_PKEY_PARAM_RSA_FACTOR5>) <unsigned integer>
408
409=item "rsa-factor6" (B<OSSL_PKEY_PARAM_RSA_FACTOR6>) <unsigned integer>
410
411=item "rsa-factor7" (B<OSSL_PKEY_PARAM_RSA_FACTOR7>) <unsigned integer>
412
413=item "rsa-factor8" (B<OSSL_PKEY_PARAM_RSA_FACTOR8>) <unsigned integer>
414
415=item "rsa-factor9" (B<OSSL_PKEY_PARAM_RSA_FACTOR9>) <unsigned integer>
416
417=item "rsa-factor10" (B<OSSL_PKEY_PARAM_RSA_FACTOR10>) <unsigned integer>
418
419RSA prime factors. The factors are known as "p", "q" and "r_i" in RFC8017.
420Up to eight additional "r_i" prime factors are supported.
421
422=item "rsa-exponent1" (B<OSSL_PKEY_PARAM_RSA_EXPONENT1>) <unsigned integer>
423
424=item "rsa-exponent2" (B<OSSL_PKEY_PARAM_RSA_EXPONENT2>) <unsigned integer>
425
426=item "rsa-exponent3" (B<OSSL_PKEY_PARAM_RSA_EXPONENT3>) <unsigned integer>
427
428=item "rsa-exponent4" (B<OSSL_PKEY_PARAM_RSA_EXPONENT4>) <unsigned integer>
429
430=item "rsa-exponent5" (B<OSSL_PKEY_PARAM_RSA_EXPONENT5>) <unsigned integer>
431
432=item "rsa-exponent6" (B<OSSL_PKEY_PARAM_RSA_EXPONENT6>) <unsigned integer>
433
434=item "rsa-exponent7" (B<OSSL_PKEY_PARAM_RSA_EXPONENT7>) <unsigned integer>
435
436=item "rsa-exponent8" (B<OSSL_PKEY_PARAM_RSA_EXPONENT8>) <unsigned integer>
437
438=item "rsa-exponent9" (B<OSSL_PKEY_PARAM_RSA_EXPONENT9>) <unsigned integer>
439
440=item "rsa-exponent10" (B<OSSL_PKEY_PARAM_RSA_EXPONENT10>) <unsigned integer>
441
442RSA CRT (Chinese Remainder Theorem) exponents. The exponents are known
443as "dP", "dQ" and "d_i in RFC8017".
444Up to eight additional "d_i" exponents are supported.
445
446=item "rsa-coefficient1" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT1>) <unsigned integer>
447
448=item "rsa-coefficient2" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT2>) <unsigned integer>
449
450=item "rsa-coefficient3" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT3>) <unsigned integer>
451
452=item "rsa-coefficient4" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT4>) <unsigned integer>
453
454=item "rsa-coefficient5" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT5>) <unsigned integer>
455
456=item "rsa-coefficient6" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT6>) <unsigned integer>
457
458=item "rsa-coefficient7" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT7>) <unsigned integer>
459
460=item "rsa-coefficient8" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT8>) <unsigned integer>
461
462=item "rsa-coefficient9" (B<OSSL_PKEY_PARAM_RSA_COEFFICIENT9>) <unsigned integer>
463
464RSA CRT (Chinese Remainder Theorem) coefficients. The coefficients are known as
465"qInv" and "t_i".
466Up to eight additional "t_i" exponents are supported.
467
468=back
469
470=head2 Built-in DSA and Diffie-Hellman Import/Export Types
471
472The following Import/Export types are available for the built-in DSA and
473Diffie-Hellman algorithms:
474
475=over 4
476
477=item "pub" (B<OSSL_PKEY_PARAM_PUB_KEY>) <unsigned integer>
478
479The public key value.
480
481=item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <unsigned integer>
482
483The private key value.
484
485=item "p" (B<OSSL_PKEY_PARAM_FFC_P>) <unsigned integer>
486
487A DSA or Diffie-Hellman "p" value.
488
489=item "q" (B<OSSL_PKEY_PARAM_FFC_Q>) <unsigned integer>
490
491A DSA or Diffie-Hellman "q" value.
492
493=item "g" (B<OSSL_PKEY_PARAM_FFC_G>) <unsigned integer>
494
495A DSA or Diffie-Hellman "g" value.
496
497=back
498
499=head2 Built-in X25519, X448, ED25519 and ED448 Import/Export Types
500
501The following Import/Export types are available for the built-in X25519, X448,
502ED25519 and X448 algorithms:
503
504=over 4
505
506=item "pub" (B<OSSL_PKEY_PARAM_PUB_KEY>) <octet string>
507
508The public key value.
509
510=item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <octet string>
511
512The private key value.
513
514=back
515
516=head2 Built-in EC Import/Export Types
517
518The following Import/Export types are available for the built-in EC algorithm:
519
520=over 4
521
522=item "curve-name" (B<OSSL_PKEY_PARAM_EC_NAME>) <utf8 string>
523
524The EC curve name.
525
526=item "use-cofactor-flag" (B<OSSL_PKEY_PARAM_USE_COFACTOR_ECDH>) <integer>
527
528Enable Cofactor DH (ECC CDH) if this value is 1, otherwise it uses normal EC DH
529if the value is zero. The cofactor variant multiplies the shared secret by the
530EC curve's cofactor (note for some curves the cofactor is 1).
531
532=item "pub" (B<OSSL_PKEY_PARAM_PUB_KEY>) <octet string>
533
534The public key value in EC point format.
535
536=item "priv" (B<OSSL_PKEY_PARAM_PRIV_KEY>) <unsigned integer>
537
538The private key value.
539
540=back
541
542=head2 Information Parameters
543
544See L<OSSL_PARAM(3)> for further details on the parameters structure.
545
546The Built-in Import/Export Types listed above are also Information Parameters.
547Not all parameters are relevant to, or are understood by all keymgmt
548algorithms:
549
550Parameters currently recognised by built-in keymgmt algorithms
551also include the following.
552
553=over 4
554
555=item "bits" (B<OSSL_PKEY_PARAM_BITS>) <integer>
556
557The value should be the cryptographic length of the cryptosystem to
558which the key belongs, in bits. The definition of cryptographic
559length is specific to the key cryptosystem.
560
561=item "max-size" (B<OSSL_PKEY_PARAM_MAX_SIZE>) <integer>
562
563The value should be the maximum size that a caller should allocate to
564safely store a signature (called I<sig> in L<provider-signature(7)>),
565the result of asymmmetric encryption / decryption (I<out> in
566L<provider-asym_cipher(7)>, a derived secret (I<secret> in
567L<provider-keyexch(7)>, and similar data).
568
569Because an EVP_KEYMGMT method is always tightly bound to another method
570(signature, asymmetric cipher, key exchange, ...) and must be of the
571same provider, this number only needs to be synchronised with the
572dimensions handled in the rest of the same provider.
573
574=item "security-bits" (B<OSSL_PKEY_PARAM_SECURITY_BITS>) <integer>
575
576The value should be the number of security bits of the given key.
577Bits of security is defined in SP800-57.
578
579=item "use-cofactor-flag" (B<OSSL_PKEY_PARAM_USE_COFACTOR_FLAG>,
580B<OSSL_PKEY_PARAM_USE_COFACTOR_ECDH>) <integer>
581
582The value should be either 1 or 0, to respectively enable or disable
583use of the cofactor in operations using this key.
584
585In the context of a key that can be used to perform an Elliptic Curve
586Diffie-Hellman key exchange, this parameter can be used to mark a requirement
587for using the Cofactor Diffie-Hellman (CDH) variant of the key exchange
588algorithm.
589
590See also L<provider-keyexch(7)> for the related
591B<OSSL_EXCHANGE_PARAM_EC_ECDH_COFACTOR_MODE> parameter that can be set on a
592per-operation basis.
593
594=back
595
596=head1 RETURN VALUES
597
598OP_keymgmt_new() should return a valid reference to the newly created provider
599side key object, or NULL on failure.
600
601OP_keymgmt_import(), OP_keymgmt_export(), OP_keymgmt_get_params() and
602OP_keymgmt_set_params() should return 1 for success or 0 on error.
603
604OP_keymgmt_validate() should return 1 on successful validation, or 0 on
605failure.
606
607OP_keymgmt_has() should return 1 if all the selected data subsets are contained
608in the given I<keydata> or 0 otherwise.
609
610OP_keymgmt_query_operation_name() should return a pointer to a string matching
611the requested operation, or NULL if the same name used to fetch the keymgmt
612applies.
613
614OP_keymgmt_gettable_params() and OP_keymgmt_settable_params()
615OP_keymgmt_import_types(), OP_keymgmt_export_types()
616should
617always return a constant B<OSSL_PARAM> array.
618
619=head1 SEE ALSO
620
621L<provider(7)>
622
623=head1 HISTORY
624
625The KEYMGMT interface was introduced in OpenSSL 3.0.
626
627=head1 COPYRIGHT
628
629Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
630
631Licensed under the Apache License 2.0 (the "License"). You may not use
632this file except in compliance with the License. You can obtain a copy
633in the file LICENSE in the source distribution or at
634L<https://www.openssl.org/source/license.html>.
635
636=cut