1 =pod 2 3 =head1 NAME 4 5 provider-signature - The signature library E<lt>-E<gt> provider functions 6 7 =head1 SYNOPSIS 8 9 =for openssl multiple includes 10 11 #include <openssl/core_dispatch.h> 12 #include <openssl/core_names.h> 13 14 /* 15 * None of these are actual functions, but are displayed like this for 16 * the function signatures for functions that are offered as function 17 * pointers in OSSL_DISPATCH arrays. 18 */ 19 20 /* Context management */ 21 void *OSSL_FUNC_signature_newctx(void *provctx, const char *propq); 22 void OSSL_FUNC_signature_freectx(void *ctx); 23 void *OSSL_FUNC_signature_dupctx(void *ctx); 24 25 /* Get the key types that a signature algorithm supports */ 26 const char **OSSL_FUNC_signature_query_key_types(void); 27 28 /* Signing */ 29 int OSSL_FUNC_signature_sign_init(void *ctx, void *provkey, 30 const OSSL_PARAM params[]); 31 int OSSL_FUNC_signature_sign(void *ctx, unsigned char *sig, size_t *siglen, 32 size_t sigsize, const unsigned char *tbs, size_t tbslen); 33 int OSSL_FUNC_signature_sign_message_init(void *ctx, void *provkey, 34 const OSSL_PARAM params[]); 35 int OSSL_FUNC_signature_sign_message_update(void *ctx, const unsigned char *in, 36 size_t inlen); 37 int OSSL_FUNC_signature_sign_message_final(void *ctx, unsigned char *sig, 38 size_t *siglen, size_t sigsize); 39 40 /* Verifying */ 41 int OSSL_FUNC_signature_verify_init(void *ctx, void *provkey, 42 const OSSL_PARAM params[]); 43 int OSSL_FUNC_signature_verify(void *ctx, const unsigned char *sig, size_t siglen, 44 const unsigned char *tbs, size_t tbslen); 45 int OSSL_FUNC_signature_verify_message_init(void *ctx, void *provkey, 46 const OSSL_PARAM params[]); 47 int OSSL_FUNC_signature_verify_message_update(void *ctx, const unsigned char *in, 48 size_t inlen); 49 /* 50 * OSSL_FUNC_signature_verify_message_final requires that the signature to be 51 * verified is specified via a "signature" OSSL_PARAM, which is given with a 52 * previous call of OSSL_FUNC_signature_set_ctx_params(). 53 */ 54 int OSSL_FUNC_signature_verify_message_final(void *ctx); 55 56 /* Verify Recover */ 57 int OSSL_FUNC_signature_verify_recover_init(void *ctx, void *provkey, 58 const OSSL_PARAM params[]); 59 int OSSL_FUNC_signature_verify_recover(void *ctx, unsigned char *rout, 60 size_t *routlen, size_t routsize, 61 const unsigned char *sig, size_t siglen); 62 63 /* Digest Sign */ 64 int OSSL_FUNC_signature_digest_sign_init(void *ctx, const char *mdname, 65 void *provkey, 66 const OSSL_PARAM params[]); 67 int OSSL_FUNC_signature_digest_sign_update(void *ctx, const unsigned char *data, 68 size_t datalen); 69 int OSSL_FUNC_signature_digest_sign_final(void *ctx, unsigned char *sig, 70 size_t *siglen, size_t sigsize); 71 int OSSL_FUNC_signature_digest_sign(void *ctx, 72 unsigned char *sig, size_t *siglen, 73 size_t sigsize, const unsigned char *tbs, 74 size_t tbslen); 75 76 /* Digest Verify */ 77 int OSSL_FUNC_signature_digest_verify_init(void *ctx, const char *mdname, 78 void *provkey, 79 const OSSL_PARAM params[]); 80 int OSSL_FUNC_signature_digest_verify_update(void *ctx, 81 const unsigned char *data, 82 size_t datalen); 83 int OSSL_FUNC_signature_digest_verify_final(void *ctx, const unsigned char *sig, 84 size_t siglen); 85 int OSSL_FUNC_signature_digest_verify(void *ctx, const unsigned char *sig, 86 size_t siglen, const unsigned char *tbs, 87 size_t tbslen); 88 89 /* Signature parameters */ 90 int OSSL_FUNC_signature_get_ctx_params(void *ctx, OSSL_PARAM params[]); 91 const OSSL_PARAM *OSSL_FUNC_signature_gettable_ctx_params(void *ctx, 92 void *provctx); 93 int OSSL_FUNC_signature_set_ctx_params(void *ctx, const OSSL_PARAM params[]); 94 const OSSL_PARAM *OSSL_FUNC_signature_settable_ctx_params(void *ctx, 95 void *provctx); 96 /* MD parameters */ 97 int OSSL_FUNC_signature_get_ctx_md_params(void *ctx, OSSL_PARAM params[]); 98 const OSSL_PARAM * OSSL_FUNC_signature_gettable_ctx_md_params(void *ctx); 99 int OSSL_FUNC_signature_set_ctx_md_params(void *ctx, const OSSL_PARAM params[]); 100 const OSSL_PARAM * OSSL_FUNC_signature_settable_ctx_md_params(void *ctx); 101 102 =head1 DESCRIPTION 103 104 This documentation is primarily aimed at provider authors. See L<provider(7)> 105 for further information. 106 107 The signature (OSSL_OP_SIGNATURE) operation enables providers to implement 108 signature algorithms and make them available to applications via the API 109 functions L<EVP_PKEY_sign(3)>, L<EVP_PKEY_verify(3)>, 110 and L<EVP_PKEY_verify_recover(3)> (as well as other related functions). 111 112 All "functions" mentioned here are passed as function pointers between 113 F<libcrypto> and the provider in L<OSSL_DISPATCH(3)> arrays via 114 L<OSSL_ALGORITHM(3)> arrays that are returned by the provider's 115 provider_query_operation() function 116 (see L<provider-base(7)/Provider Functions>). 117 118 All these "functions" have a corresponding function type definition 119 named B<OSSL_FUNC_{name}_fn>, and a helper function to retrieve the 120 function pointer from an L<OSSL_DISPATCH(3)> element named 121 B<OSSL_FUNC_{name}>. 122 For example, the "function" OSSL_FUNC_signature_newctx() has these: 123 124 typedef void *(OSSL_FUNC_signature_newctx_fn)(void *provctx, const char *propq); 125 static ossl_inline OSSL_FUNC_signature_newctx_fn 126 OSSL_FUNC_signature_newctx(const OSSL_DISPATCH *opf); 127 128 L<OSSL_DISPATCH(3)> arrays are indexed by numbers that are provided as 129 macros in L<openssl-core_dispatch.h(7)>, as follows: 130 131 OSSL_FUNC_signature_newctx OSSL_FUNC_SIGNATURE_NEWCTX 132 OSSL_FUNC_signature_freectx OSSL_FUNC_SIGNATURE_FREECTX 133 OSSL_FUNC_signature_dupctx OSSL_FUNC_SIGNATURE_DUPCTX 134 135 OSSL_FUNC_signature_query_key_types OSSL_FUNC_SIGNATURE_QUERY_KEY_TYPES 136 137 OSSL_FUNC_signature_sign_init OSSL_FUNC_SIGNATURE_SIGN_INIT 138 OSSL_FUNC_signature_sign OSSL_FUNC_SIGNATURE_SIGN 139 OSSL_FUNC_signature_sign_message_init OSSL_FUNC_SIGNATURE_SIGN_MESSAGE_INIT 140 OSSL_FUNC_signature_sign_message_update OSSL_FUNC_SIGNATURE_SIGN_MESSAGE_UPDATE 141 OSSL_FUNC_signature_sign_message_final OSSL_FUNC_SIGNATURE_SIGN_MESSAGE_FINAL 142 143 OSSL_FUNC_signature_verify_init OSSL_FUNC_SIGNATURE_VERIFY_INIT 144 OSSL_FUNC_signature_verify OSSL_FUNC_SIGNATURE_VERIFY 145 OSSL_FUNC_signature_verify_message_init OSSL_FUNC_SIGNATURE_VERIFY_MESSAGE_INIT 146 OSSL_FUNC_signature_verify_message_update OSSL_FUNC_SIGNATURE_VERIFY_MESSAGE_UPDATE 147 OSSL_FUNC_signature_verify_message_final OSSL_FUNC_SIGNATURE_VERIFY_MESSAGE_FINAL 148 149 OSSL_FUNC_signature_verify_recover_init OSSL_FUNC_SIGNATURE_VERIFY_RECOVER_INIT 150 OSSL_FUNC_signature_verify_recover OSSL_FUNC_SIGNATURE_VERIFY_RECOVER 151 152 OSSL_FUNC_signature_digest_sign_init OSSL_FUNC_SIGNATURE_DIGEST_SIGN_INIT 153 OSSL_FUNC_signature_digest_sign_update OSSL_FUNC_SIGNATURE_DIGEST_SIGN_UPDATE 154 OSSL_FUNC_signature_digest_sign_final OSSL_FUNC_SIGNATURE_DIGEST_SIGN_FINAL 155 OSSL_FUNC_signature_digest_sign OSSL_FUNC_SIGNATURE_DIGEST_SIGN 156 157 OSSL_FUNC_signature_digest_verify_init OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_INIT 158 OSSL_FUNC_signature_digest_verify_update OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_UPDATE 159 OSSL_FUNC_signature_digest_verify_final OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_FINAL 160 OSSL_FUNC_signature_digest_verify OSSL_FUNC_SIGNATURE_DIGEST_VERIFY 161 162 OSSL_FUNC_signature_get_ctx_params OSSL_FUNC_SIGNATURE_GET_CTX_PARAMS 163 OSSL_FUNC_signature_gettable_ctx_params OSSL_FUNC_SIGNATURE_GETTABLE_CTX_PARAMS 164 OSSL_FUNC_signature_set_ctx_params OSSL_FUNC_SIGNATURE_SET_CTX_PARAMS 165 OSSL_FUNC_signature_settable_ctx_params OSSL_FUNC_SIGNATURE_SETTABLE_CTX_PARAMS 166 167 OSSL_FUNC_signature_get_ctx_md_params OSSL_FUNC_SIGNATURE_GET_CTX_MD_PARAMS 168 OSSL_FUNC_signature_gettable_ctx_md_params OSSL_FUNC_SIGNATURE_GETTABLE_CTX_MD_PARAMS 169 OSSL_FUNC_signature_set_ctx_md_params OSSL_FUNC_SIGNATURE_SET_CTX_MD_PARAMS 170 OSSL_FUNC_signature_settable_ctx_md_params OSSL_FUNC_SIGNATURE_SETTABLE_CTX_MD_PARAMS 171 172 A signature algorithm implementation may not implement all of these functions. 173 In order to be a consistent set of functions we must have at least a set of 174 context functions (OSSL_FUNC_signature_newctx and OSSL_FUNC_signature_freectx) as well as a 175 set of "signature" functions, i.e. at least one of: 176 177 =over 4 178 179 =item OSSL_FUNC_signature_sign_init and OSSL_FUNC_signature_sign 180 181 Used via L<EVP_PKEY_sign_init(3)> and L<EVP_PKEY_sign(3)>. 182 These functions operate on pre-digested data (the "to be signed" or TBS value). 183 184 =item OSSL_FUNC_signature_sign_message_init and OSSL_FUNC_signature_sign 185 186 Used via L<EVP_PKEY_sign_message_init(3)> and L<EVP_PKEY_sign(3)> when signing a complete message. 187 The implementation internally handles message digesting. 188 189 =item OSSL_FUNC_signature_sign_message_init, OSSL_FUNC_signature_sign_message_update and OSSL_FUNC_signature_sign_message_final 190 191 Streaming variant of message signing, used via L<EVP_PKEY_sign_message_init(3)>, 192 L<EVP_PKEY_sign_message_update(3)>, and L<EVP_PKEY_sign_message_final(3)>. 193 194 =item OSSL_FUNC_signature_verify_init and OSSL_FUNC_signature_verify 195 196 Used via L<EVP_PKEY_verify_init(3)> and L<EVP_PKEY_verify(3)>. 197 These functions operate on pre-digested data. 198 199 =item OSSL_FUNC_signature_verify_message_init and OSSL_FUNC_signature_verify 200 201 Used via L<EVP_PKEY_verify_message_init(3)> and L<EVP_PKEY_verify(3)> when verifying a complete message. 202 The implementation internally handles message digesting. 203 204 =item OSSL_FUNC_signature_verify_message_init, OSSL_FUNC_signature_verify_message_update and OSSL_FUNC_signature_verify_message_final 205 206 Streaming variant of message verification, used via L<EVP_PKEY_verify_message_init(3)>, 207 L<EVP_PKEY_verify_message_update(3)>, and L<EVP_PKEY_verify_message_final(3)>. 208 209 =item OSSL_FUNC_signature_verify_recover_init and OSSL_FUNC_signature_verify_recover 210 211 Used via L<EVP_PKEY_verify_recover_init(3)> and L<EVP_PKEY_verify_recover(3)>. 212 Applicable only to signature schemes that support signature recovery (such as RSA). 213 214 =item OSSL_FUNC_signature_digest_sign_init, OSSL_FUNC_signature_digest_sign_update and OSSL_FUNC_signature_digest_sign_final 215 216 Streaming digest-sign variant, used via L<EVP_DigestSignInit(3)>, 217 L<EVP_DigestSignUpdate(3)>, and L<EVP_DigestSignFinal(3)>. 218 219 =item OSSL_FUNC_signature_digest_verify_init, OSSL_FUNC_signature_digest_verify_update and OSSL_FUNC_signature_digest_verify_final 220 221 Streaming digest-verify variant, used via L<EVP_DigestVerifyInit(3)>, 222 L<EVP_DigestVerifyUpdate(3)>, and L<EVP_DigestVerifyFinal(3)>. 223 224 =item OSSL_FUNC_signature_digest_sign_init and OSSL_FUNC_signature_digest_sign 225 226 One-shot digest-sign variant, used via L<EVP_DigestSign(3)>. 227 228 =item OSSL_FUNC_signature_digest_verify_init and OSSL_FUNC_signature_digest_verify 229 230 One-shot digest-verify variant, used via L<EVP_DigestVerify(3)>. 231 232 =back 233 234 B<Important Note for TLS Support:> For a provider signature implementation to 235 be usable within F<libssl> for TLS connections, it B<must> implement the 236 digest-sign and digest-verify functions 237 (OSSL_FUNC_signature_digest_sign_init/update/final or the one-shot variant, and 238 OSSL_FUNC_signature_digest_verify_init/update/final or the one-shot variant). 239 The TLS handshake code in F<libssl> specifically requires these digest functions 240 and will not use implementations that only provide the basic sign/verify functions 241 (OSSL_FUNC_signature_sign_init/sign or OSSL_FUNC_signature_verify_init/verify). 242 243 The choice of which function set to implement depends on your use case: 244 245 =over 4 246 247 =item * 248 249 For general-purpose signature operations and TLS support: implement the 250 digest-sign and digest-verify functions. 251 252 =item * 253 254 For operations on pre-digested data only: implement the basic sign and verify 255 functions. 256 257 =item * 258 259 For signature schemes with recovery capability: additionally implement the 260 verify-recover functions. 261 262 =back 263 264 The OSSL_FUNC_signature_set_ctx_params() and 265 OSSL_FUNC_signature_settable_ctx_params() functions are optional, 266 but if one of them is provided then the other one must also be provided. 267 The same applies to the OSSL_FUNC_signature_get_ctx_params() and 268 OSSL_FUNC_signature_gettable_ctx_params() functions, 269 as well as the "md_params" functions. 270 271 The OSSL_FUNC_signature_dupctx() function is optional. 272 273 The OSSL_FUNC_signature_query_key_types() function is optional. 274 When present, it should return a NULL-terminated array of strings 275 indicating the key types supported by the provider for signature operations. 276 Otherwise the signature algorithm name must match the given key 277 or match the default signature algorithm name of the key, 278 both checked using L<EVP_SIGNATURE_is_a(3)>. 279 280 A signature algorithm must also implement some mechanism for generating, 281 loading or importing keys via the key management (OSSL_OP_KEYMGMT) operation. 282 See L<provider-keymgmt(7)> for further details. 283 284 =head2 Context Management Functions 285 286 OSSL_FUNC_signature_newctx() should create and return a pointer to a provider side 287 structure for holding context information during a signature operation. 288 A pointer to this context will be passed back in a number of the other signature 289 operation function calls. 290 The parameter I<provctx> is the provider context generated during provider 291 initialisation (see L<provider(7)>). The I<propq> parameter is a property query 292 string that may be (optionally) used by the provider during any "fetches" that 293 it may perform (if it performs any). 294 295 OSSL_FUNC_signature_freectx() is passed a pointer to the provider side signature 296 context in the I<ctx> parameter. 297 This function should free any resources associated with that context. 298 299 OSSL_FUNC_signature_dupctx() should duplicate the provider side signature context in 300 the I<ctx> parameter and return the duplicate copy. 301 302 =head2 Signing Functions 303 304 OSSL_FUNC_signature_sign_init() initialises a context for signing given a provider side 305 signature context in the I<ctx> parameter, and a pointer to a provider key object 306 in the I<provkey> parameter. 307 The I<params>, if not NULL, should be set on the context in a manner similar to 308 using OSSL_FUNC_signature_set_ctx_params(). 309 The key object should have been previously generated, loaded or imported into 310 the provider using the key management (OSSL_OP_KEYMGMT) operation (see 311 L<provider-keymgmt(7)>). 312 313 OSSL_FUNC_signature_sign() performs the actual signing itself. 314 A previously initialised signature context is passed in the I<ctx> 315 parameter. 316 The data to be signed is pointed to be the I<tbs> parameter which is I<tbslen> 317 bytes long. 318 Unless I<sig> is NULL, the signature should be written to the location pointed 319 to by the I<sig> parameter and it should not exceed I<sigsize> bytes in length. 320 The length of the signature should be written to I<*siglen>. 321 If I<sig> is NULL then the maximum length of the signature should be written to 322 I<*siglen>. 323 324 =head2 Message Signing Functions 325 326 These functions are suitable for providers that implement algorithms that 327 accumulate a full message and sign the result of that accumulation, such as 328 RSA-SHA256. 329 330 OSSL_FUNC_signature_sign_message_init() initialises a context for signing a 331 message given a provider side signature context in the I<ctx> parameter, and a 332 pointer to a provider key object in the I<provkey> parameter. 333 The I<params>, if not NULL, should be set on the context in a manner similar to 334 using OSSL_FUNC_signature_set_ctx_params(). 335 The key object should have been previously generated, loaded or imported into 336 the provider using the key management (OSSL_OP_KEYMGMT) operation (see 337 L<provider-keymgmt(7)>). 338 339 OSSL_FUNC_signature_sign_message_update() gathers the data pointed at by 340 I<in>, which is I<inlen> bytes long. 341 342 OSSL_FUNC_signature_sign_message_final() performs the actual signing on the 343 data that was gathered with OSSL_FUNC_signature_sign_message_update(). 344 345 OSSL_FUNC_signature_sign() can be used for one-shot signature calls. In that 346 case, I<tbs> is expected to be the whole message to be signed, I<tbslen> bytes 347 long. 348 349 For both OSSL_FUNC_signature_sign_message_final() and OSSL_FUNC_signature_sign(), 350 if I<sig> is not NULL, the signature should be written to the location pointed 351 to by I<sig>, and it should not exceed I<sigsize> bytes in length. 352 The length of the signature should be written to I<*siglen>. 353 If I<sig> is NULL then the maximum length of the signature should be written to 354 I<*siglen>. 355 356 =head2 Verify Functions 357 358 OSSL_FUNC_signature_verify_init() initialises a context for verifying a signature given 359 a provider side signature context in the I<ctx> parameter, and a pointer to a 360 provider key object in the I<provkey> parameter. 361 The I<params>, if not NULL, should be set on the context in a manner similar to 362 using OSSL_FUNC_signature_set_ctx_params(). 363 The key object should have been previously generated, loaded or imported into 364 the provider using the key management (OSSL_OP_KEYMGMT) operation (see 365 L<provider-keymgmt(7)>). 366 367 OSSL_FUNC_signature_verify() performs the actual verification itself. 368 A previously initialised signature context is passed in the I<ctx> parameter. 369 The data that the signature covers is pointed to be the I<tbs> parameter which 370 is I<tbslen> bytes long. 371 The signature is pointed to by the I<sig> parameter which is I<siglen> bytes 372 long. 373 374 =head2 Message Verify Functions 375 376 These functions are suitable for providers that implement algorithms that 377 accumulate a full message and verify a signature on the result of that 378 accumulation, such as RSA-SHA256. 379 380 OSSL_FUNC_signature_verify_message_init() initialises a context for verifying 381 a signature on a message given a provider side signature context in the I<ctx> 382 parameter, and a pointer to a provider key object in the I<provkey> parameter. 383 The I<params>, if not NULL, should be set on the context in a manner similar to 384 using OSSL_FUNC_signature_set_ctx_params(). 385 The key object should have been previously generated, loaded or imported into 386 the provider using the key management (OSSL_OP_KEYMGMT) operation (see 387 L<provider-keymgmt(7)>). 388 389 OSSL_FUNC_signature_verify_message_update() gathers the data pointed at by 390 I<in>, which is I<inlen> bytes long. 391 392 OSSL_FUNC_signature_verify_message_final() performs the actual verification on 393 the data that was gathered with OSSL_FUNC_signature_verify_message_update(). 394 The signature itself must have been passed through the "signature" 395 (B<OSSL_SIGNATURE_PARAM_SIGNATURE>) L<Signature parameter|/Signature parameters> 396 before this function is called. 397 398 OSSL_FUNC_signature_verify() can be used for one-shot verification calls. In 399 that case, I<tbs> is expected to be the whole message to be verified on, 400 I<tbslen> bytes long. 401 402 =head2 Verify Recover Functions 403 404 OSSL_FUNC_signature_verify_recover_init() initialises a context for recovering the 405 signed data given a provider side signature context in the I<ctx> parameter, and 406 a pointer to a provider key object in the I<provkey> parameter. 407 The I<params>, if not NULL, should be set on the context in a manner similar to 408 using OSSL_FUNC_signature_set_ctx_params(). 409 The key object should have been previously generated, loaded or imported into 410 the provider using the key management (OSSL_OP_KEYMGMT) operation (see 411 L<provider-keymgmt(7)>). 412 413 OSSL_FUNC_signature_verify_recover() performs the actual verify recover itself. 414 A previously initialised signature context is passed in the I<ctx> parameter. 415 The signature is pointed to by the I<sig> parameter which is I<siglen> bytes 416 long. 417 Unless I<rout> is NULL, the recovered data should be written to the location 418 pointed to by I<rout> which should not exceed I<routsize> bytes in length. 419 The length of the recovered data should be written to I<*routlen>. 420 If I<rout> is NULL then the maximum size of the output buffer is written to 421 the I<routlen> parameter. 422 423 =head2 Digest Sign Functions 424 425 OSSL_FUNC_signature_digest_sign_init() initialises a context for signing given a 426 provider side signature context in the I<ctx> parameter, and a pointer to a 427 provider key object in the I<provkey> parameter. 428 The I<params>, if not NULL, should be set on the context in a manner similar to 429 using OSSL_FUNC_signature_set_ctx_params() and 430 OSSL_FUNC_signature_set_ctx_md_params(). 431 The key object should have been 432 previously generated, loaded or imported into the provider using the 433 key management (OSSL_OP_KEYMGMT) operation (see L<provider-keymgmt(7)>). 434 The name of the digest to be used will be in the I<mdname> parameter. 435 436 OSSL_FUNC_signature_digest_sign_update() provides data to be signed in the I<data> 437 parameter which should be of length I<datalen>. A previously initialised 438 signature context is passed in the I<ctx> parameter. This function may be called 439 multiple times to cumulatively add data to be signed. 440 441 OSSL_FUNC_signature_digest_sign_final() finalises a signature operation previously 442 started through OSSL_FUNC_signature_digest_sign_init() and 443 OSSL_FUNC_signature_digest_sign_update() calls. Once finalised no more data will be 444 added through OSSL_FUNC_signature_digest_sign_update(). A previously initialised 445 signature context is passed in the I<ctx> parameter. Unless I<sig> is NULL, the 446 signature should be written to the location pointed to by the I<sig> parameter 447 and it should not exceed I<sigsize> bytes in length. The length of the signature 448 should be written to I<*siglen>. If I<sig> is NULL then the maximum length of 449 the signature should be written to I<*siglen>. 450 451 OSSL_FUNC_signature_digest_sign() implements a "one shot" digest sign operation 452 previously started through OSSL_FUNC_signature_digest_sign_init(). A previously 453 initialised signature context is passed in the I<ctx> parameter. The data to be 454 signed is in I<tbs> which should be I<tbslen> bytes long. Unless I<sig> is NULL, 455 the signature should be written to the location pointed to by the I<sig> 456 parameter and it should not exceed I<sigsize> bytes in length. The length of the 457 signature should be written to I<*siglen>. If I<sig> is NULL then the maximum 458 length of the signature should be written to I<*siglen>. 459 460 =head2 Digest Verify Functions 461 462 OSSL_FUNC_signature_digest_verify_init() initialises a context for verifying given a 463 provider side verification context in the I<ctx> parameter, and a pointer to a 464 provider key object in the I<provkey> parameter. 465 The I<params>, if not NULL, should be set on the context in a manner similar to 466 OSSL_FUNC_signature_set_ctx_params() and 467 OSSL_FUNC_signature_set_ctx_md_params(). 468 The key object should have been 469 previously generated, loaded or imported into the provider using the 470 key management (OSSL_OP_KEYMGMT) operation (see L<provider-keymgmt(7)>). 471 The name of the digest to be used will be in the I<mdname> parameter. 472 473 OSSL_FUNC_signature_digest_verify_update() provides data to be verified in the I<data> 474 parameter which should be of length I<datalen>. A previously initialised 475 verification context is passed in the I<ctx> parameter. This function may be 476 called multiple times to cumulatively add data to be verified. 477 478 OSSL_FUNC_signature_digest_verify_final() finalises a verification operation previously 479 started through OSSL_FUNC_signature_digest_verify_init() and 480 OSSL_FUNC_signature_digest_verify_update() calls. Once finalised no more data will be 481 added through OSSL_FUNC_signature_digest_verify_update(). A previously initialised 482 verification context is passed in the I<ctx> parameter. The signature to be 483 verified is in I<sig> which is I<siglen> bytes long. 484 485 OSSL_FUNC_signature_digest_verify() implements a "one shot" digest verify operation 486 previously started through OSSL_FUNC_signature_digest_verify_init(). A previously 487 initialised verification context is passed in the I<ctx> parameter. The data to be 488 verified is in I<tbs> which should be I<tbslen> bytes long. The signature to be 489 verified is in I<sig> which is I<siglen> bytes long. 490 491 =head2 Signature parameters 492 493 See L<OSSL_PARAM(3)> for further details on the parameters structure used by 494 the OSSL_FUNC_signature_get_ctx_params() and OSSL_FUNC_signature_set_ctx_params() functions. 495 496 OSSL_FUNC_signature_get_ctx_params() gets signature parameters associated with the 497 given provider side signature context I<ctx> and stored them in I<params>. 498 Passing NULL for I<params> should return true. 499 500 OSSL_FUNC_signature_set_ctx_params() sets the signature parameters associated with the 501 given provider side signature context I<ctx> to I<params>. 502 Any parameter settings are additional to any that were previously set. 503 Passing NULL for I<params> should return true. 504 505 Common parameters currently recognised by built-in signature algorithms are as 506 follows. 507 508 =over 4 509 510 =item "digest" (B<OSSL_SIGNATURE_PARAM_DIGEST>) <UTF8 string> 511 512 Get or sets the name of the digest algorithm used for the input to the 513 signature functions. It is required in order to calculate the "algorithm-id". 514 515 =item "properties" (B<OSSL_SIGNATURE_PARAM_PROPERTIES>) <UTF8 string> 516 517 Sets the name of the property query associated with the "digest" algorithm. 518 NULL is used if this optional value is not set. 519 520 =back 521 522 Note that when implementing a signature algorithm that gathers a full message, 523 like RSA-SHA256, the "digest" and "properties" parameters should not be used. 524 For such implementations, it's acceptable to simply ignore them if they happen 525 to be passed in a call to OSSL_FUNC_signature_set_ctx_params(). For such 526 implementations, however, it is not acceptable to have them in the B<OSSL_PARAM> 527 array that's returned by OSSL_FUNC_signature_settable_ctx_params(). 528 529 =over 4 530 531 =item "signature" (B<OSSL_SIGNATURE_PARAM_SIGNATURE>) <octet string> 532 533 Sets the signature to verify, specifically when 534 OSSL_FUNC_signature_verify_message_final() is used. 535 536 =item "digest-size" (B<OSSL_SIGNATURE_PARAM_DIGEST_SIZE>) <unsigned integer> 537 538 Gets or sets the output size of the digest algorithm used for the input to the 539 signature functions. 540 The length of the "digest-size" parameter should not exceed that of a B<size_t>. 541 542 =item "algorithm-id" (B<OSSL_SIGNATURE_PARAM_ALGORITHM_ID>) <octet string> 543 544 Gets the DER-encoded AlgorithmIdentifier for the signature operation. 545 This typically corresponds to the combination of a digest algorithm 546 with a purely asymmetric signature algorithm, such as SHA256WithECDSA. 547 548 The L<ASN1_item_sign_ctx(3)> function relies on this operation and is used by 549 many other functions that sign ASN.1 structures such as X.509 certificates, 550 certificate requests, and CRLs, as well as OCSP, CMP, and CMS messages. 551 552 =item "nonce-type" (B<OSSL_SIGNATURE_PARAM_NONCE_TYPE>) <unsigned integer> 553 554 Set this to 1 to use deterministic digital signature generation with 555 ECDSA or DSA, as defined in RFC 6979 (see Section 3.2 "Generation of 556 k"). In this case, the "digest" parameter must be explicitly set 557 (otherwise, deterministic nonce generation will fail). Before using 558 deterministic digital signature generation, please read RFC 6979 559 Section 4 "Security Considerations". The default value for 560 "nonce-type" is 0 and results in a random value being used for the 561 nonce B<k> as defined in FIPS 186-4 Section 6.3 "Secret Number 562 Generation". 563 564 The FIPS provider does not support deterministic digital signature generation. 565 566 =item "kat" (B<OSSL_SIGNATURE_PARAM_KAT>) <unsigned integer> 567 568 Sets a flag to modify the sign operation to return an error if the initial 569 calculated signature is invalid. 570 In the normal mode of operation - new random values are chosen until the 571 signature operation succeeds. 572 By default it retries until a signature is calculated. 573 Setting the value to 0 causes the sign operation to retry, 574 otherwise the sign operation is only tried once and returns whether or not it 575 was successful. 576 Known answer tests can be performed if the random generator is overridden to 577 supply known values that either pass or fail. 578 579 =back 580 581 The following parameters are used by the OpenSSL FIPS provider: 582 583 =over 4 584 585 =item "fips-indicator" (B<OSSL_SIGNATURE_PARAM_FIPS_APPROVED_INDICATOR>) <integer> 586 587 A getter that returns 1 if the operation is FIPS approved, or 0 otherwise. 588 This may be used after calling either the sign or verify final functions. It may 589 return 0 if either the "digest-check", "key-check", or "sign-check" are set to 0. 590 591 =item "verify-message" (B<OSSL_SIGNATURE_PARAM_FIPS_VERIFY_MESSAGE> <integer> 592 593 A getter that returns 1 if a signature verification operation acted on 594 a raw message, or 0 if it verified a predigested message. A value of 0 595 indicates likely non-approved usage of the FIPS provider. This flag is 596 set when any signature verification initialisation function is called. 597 It is also set to 1 when any signing operation is performed to signify 598 compliance. See FIPS 140-3 IG 2.4.B for further information. 599 600 =item "key-check" (B<OSSL_SIGNATURE_PARAM_FIPS_KEY_CHECK>) <integer> 601 602 If required this parameter should be set early via an init function 603 (e.g. OSSL_FUNC_signature_sign_init() or OSSL_FUNC_signature_verify_init()). 604 The default value of 1 causes an error during the init if the key is not FIPS 605 approved (e.g. The key has a security strength of less than 112 bits). 606 Setting this to 0 will ignore the error and set the approved "indicator" to 0. 607 This option breaks FIPS compliance if it causes the approved "fips-indicator" 608 to return 0. 609 610 =item "digest-check" (B<OSSL_SIGNATURE_PARAM_FIPS_DIGEST_CHECK>) <integer> 611 612 If required this parameter should be set before the signature digest is set. 613 The default value of 1 causes an error when the digest is set if the digest is 614 not FIPS approved (e.g. SHA1 is used for signing). Setting this to 0 will ignore 615 the error and set the approved "fips-indicator" to 0. 616 This option breaks FIPS compliance if it causes the approved "fips-indicator" 617 to return 0. 618 619 =item "sign-check" (B<OSSL_SIGNATURE_PARAM_FIPS_SIGN_CHECK>) <integer> 620 621 If required this parameter should be set early via an init function. 622 The default value of 1 causes an error when a signing algorithm is used. (This 623 is triggered by deprecated signing algorithms). 624 Setting this to 0 will ignore the error and set the approved "fips-indicator" to 0. 625 This option breaks FIPS compliance if it causes the approved "fips-indicator" to 626 return 0. 627 628 =item "sign-x931-pad-check" (B<OSSL_SIGNATURE_PARAM_FIPS_SIGN_X931_PAD_CHECK>) <integer> 629 630 If required this parameter should be set before the padding mode is set. 631 The default value of 1 causes an error if the padding mode is set to X9.31 padding 632 for a RSA signing operation. Setting this to 0 will ignore the error and set the 633 approved "fips-indicator" to 0. 634 This option breaks FIPS compliance if it causes the approved "fips-indicator" 635 to return 0. 636 637 =back 638 639 OSSL_FUNC_signature_gettable_ctx_params() and OSSL_FUNC_signature_settable_ctx_params() get a 640 constant L<OSSL_PARAM(3)> array that describes the gettable and settable parameters, 641 i.e. parameters that can be used with OSSL_FUNC_signature_get_ctx_params() and 642 OSSL_FUNC_signature_set_ctx_params() respectively. 643 644 =head2 MD parameters 645 646 See L<OSSL_PARAM(3)> for further details on the parameters structure used by 647 the OSSL_FUNC_signature_get_md_ctx_params() and OSSL_FUNC_signature_set_md_ctx_params() 648 functions. 649 650 OSSL_FUNC_signature_get_md_ctx_params() gets digest parameters associated with the 651 given provider side digest signature context I<ctx> and stores them in I<params>. 652 Passing NULL for I<params> should return true. 653 654 OSSL_FUNC_signature_set_ms_ctx_params() sets the digest parameters associated with the 655 given provider side digest signature context I<ctx> to I<params>. 656 Any parameter settings are additional to any that were previously set. 657 Passing NULL for I<params> should return true. 658 659 Parameters currently recognised by built-in signature algorithms are the same 660 as those for built-in digest algorithms. See 661 L<provider-digest(7)/Digest Parameters> for further information. 662 663 OSSL_FUNC_signature_gettable_md_ctx_params() and OSSL_FUNC_signature_settable_md_ctx_params() 664 get a constant L<OSSL_PARAM(3)> array that describes the gettable and settable 665 digest parameters, i.e. parameters that can be used with 666 OSSL_FUNC_signature_get_md_ctx_params() and OSSL_FUNC_signature_set_md_ctx_params() 667 respectively. 668 669 =head1 RETURN VALUES 670 671 OSSL_FUNC_signature_newctx() and OSSL_FUNC_signature_dupctx() should return the newly created 672 provider side signature context, or NULL on failure. 673 674 OSSL_FUNC_signature_gettable_ctx_params(), OSSL_FUNC_signature_settable_ctx_params(), 675 OSSL_FUNC_signature_gettable_md_ctx_params() and OSSL_FUNC_signature_settable_md_ctx_params(), 676 return the gettable or settable parameters in a constant L<OSSL_PARAM(3)> array. 677 678 OSSL_FUNC_signature_query_key_types() should return a NULL-terminated array of strings. 679 680 All verification functions should return 1 for success, 681 0 for a non-matching signature, and a negative value for operation failure. 682 683 All other functions should return 1 for success 684 and 0 or a negative value for failure. 685 686 =head1 SEE ALSO 687 688 L<provider(7)>, L<provider-base(7)/Provider Functions>, 689 L<OSSL_PARAM(3)>, L<OSSL_DISPATCH(3)>, L<OSSL_ALGORITHM(3)>, 690 L<EVP_PKEY_sign(3)>, L<EVP_PKEY_verify(3)>, L<EVP_PKEY_verify_recover(3)>, 691 L<EVP_SIGNATURE_is_a(3)>, L<ASN1_item_sign_ctx(3)> 692 693 =head1 HISTORY 694 695 The provider SIGNATURE interface was introduced in OpenSSL 3.0. 696 697 The OSSL_FUNC_signature_sign_message_init(), OSSL_FUNC_signature_sign_message_update(), 698 OSSL_FUNC_signature_sign_message_final(), OSSL_FUNC_signature_verify_message_init(), 699 OSSL_FUNC_signature_verify_message_update() and OSSL_FUNC_signature_verify_message_final() 700 functions were added in OpenSSL 3.4. 701 702 The Signature Parameters "fips-indicator", "key-check" and "digest-check" were added in 703 OpenSSL 3.4. 704 705 Deterministic digital signature generation for ECDSA was added to the FIPS provider in OpenSSL 706 3.6. 707 708 =head1 COPYRIGHT 709 710 Copyright 2019-2026 The OpenSSL Project Authors. All Rights Reserved. 711 712 Licensed under the Apache License 2.0 (the "License"). You may not use 713 this file except in compliance with the License. You can obtain a copy 714 in the file LICENSE in the source distribution or at 715 L<https://www.openssl.org/source/license.html>. 716 717 =cut 718
Indexes created Sat Oct 10 00:27:21 UTC 2026