1 =pod 2 3 =head1 NAME 4 5 provider-asym_cipher - The asym_cipher 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_asym_cipher_newctx(void *provctx); 22 void OSSL_FUNC_asym_cipher_freectx(void *ctx); 23 void *OSSL_FUNC_asym_cipher_dupctx(void *ctx); 24 25 /* Encryption */ 26 int OSSL_FUNC_asym_cipher_encrypt_init(void *ctx, void *provkey, 27 const OSSL_PARAM params[]); 28 int OSSL_FUNC_asym_cipher_encrypt(void *ctx, unsigned char *out, size_t *outlen, 29 size_t outsize, const unsigned char *in, 30 size_t inlen); 31 32 /* Decryption */ 33 int OSSL_FUNC_asym_cipher_decrypt_init(void *ctx, void *provkey, 34 const OSSL_PARAM params[]); 35 int OSSL_FUNC_asym_cipher_decrypt(void *ctx, unsigned char *out, size_t *outlen, 36 size_t outsize, const unsigned char *in, 37 size_t inlen); 38 39 /* Asymmetric Cipher parameters */ 40 int OSSL_FUNC_asym_cipher_get_ctx_params(void *ctx, OSSL_PARAM params[]); 41 const OSSL_PARAM *OSSL_FUNC_asym_cipher_gettable_ctx_params(void *ctx, void *provctx); 42 int OSSL_FUNC_asym_cipher_set_ctx_params(void *ctx, const OSSL_PARAM params[]); 43 const OSSL_PARAM *OSSL_FUNC_asym_cipher_settable_ctx_params(void *ctx, void *provctx); 44 45 =head1 DESCRIPTION 46 47 This documentation is primarily aimed at provider authors. See L<provider(7)> 48 for further information. 49 50 The asymmetric cipher (OSSL_OP_ASYM_CIPHER) operation enables providers to 51 implement asymmetric cipher algorithms and make them available to applications 52 via the API functions L<EVP_PKEY_encrypt(3)>, 53 L<EVP_PKEY_decrypt(3)> and 54 other related functions). 55 56 All "functions" mentioned here are passed as function pointers between 57 F<libcrypto> and the provider in L<OSSL_DISPATCH(3)> arrays via 58 L<OSSL_ALGORITHM(3)> arrays that are returned by the provider's 59 provider_query_operation() function 60 (see L<provider-base(7)/Provider Functions>). 61 62 All these "functions" have a corresponding function type definition 63 named B<OSSL_FUNC_{name}_fn>, and a helper function to retrieve the 64 function pointer from an L<OSSL_DISPATCH(3)> element named 65 B<OSSL_FUNC_{name}>. 66 For example, the "function" OSSL_FUNC_asym_cipher_newctx() has these: 67 68 typedef void *(OSSL_FUNC_asym_cipher_newctx_fn)(void *provctx); 69 static ossl_inline OSSL_FUNC_asym_cipher_newctx_fn 70 OSSL_FUNC_asym_cipher_newctx(const OSSL_DISPATCH *opf); 71 72 L<OSSL_DISPATCH(3)> arrays are indexed by numbers that are provided as 73 macros in L<openssl-core_dispatch.h(7)>, as follows: 74 75 OSSL_FUNC_asym_cipher_newctx OSSL_FUNC_ASYM_CIPHER_NEWCTX 76 OSSL_FUNC_asym_cipher_freectx OSSL_FUNC_ASYM_CIPHER_FREECTX 77 OSSL_FUNC_asym_cipher_dupctx OSSL_FUNC_ASYM_CIPHER_DUPCTX 78 79 OSSL_FUNC_asym_cipher_encrypt_init OSSL_FUNC_ASYM_CIPHER_ENCRYPT_INIT 80 OSSL_FUNC_asym_cipher_encrypt OSSL_FUNC_ASYM_CIPHER_ENCRYPT 81 82 OSSL_FUNC_asym_cipher_decrypt_init OSSL_FUNC_ASYM_CIPHER_DECRYPT_INIT 83 OSSL_FUNC_asym_cipher_decrypt OSSL_FUNC_ASYM_CIPHER_DECRYPT 84 85 OSSL_FUNC_asym_cipher_get_ctx_params OSSL_FUNC_ASYM_CIPHER_GET_CTX_PARAMS 86 OSSL_FUNC_asym_cipher_gettable_ctx_params OSSL_FUNC_ASYM_CIPHER_GETTABLE_CTX_PARAMS 87 OSSL_FUNC_asym_cipher_set_ctx_params OSSL_FUNC_ASYM_CIPHER_SET_CTX_PARAMS 88 OSSL_FUNC_asym_cipher_settable_ctx_params OSSL_FUNC_ASYM_CIPHER_SETTABLE_CTX_PARAMS 89 90 An asymmetric cipher algorithm implementation may not implement all of these 91 functions. 92 In order to be a consistent set of functions a provider must implement 93 OSSL_FUNC_asym_cipher_newctx and OSSL_FUNC_asym_cipher_freectx. 94 It must also implement both of OSSL_FUNC_asym_cipher_encrypt_init and 95 OSSL_FUNC_asym_cipher_encrypt, or both of OSSL_FUNC_asym_cipher_decrypt_init and 96 OSSL_FUNC_asym_cipher_decrypt. 97 OSSL_FUNC_asym_cipher_get_ctx_params is optional but if it is present then so must 98 OSSL_FUNC_asym_cipher_gettable_ctx_params. 99 Similarly, OSSL_FUNC_asym_cipher_set_ctx_params is optional but if it is present then 100 so must OSSL_FUNC_asym_cipher_settable_ctx_params. 101 102 An asymmetric cipher algorithm must also implement some mechanism for generating, 103 loading or importing keys via the key management (OSSL_OP_KEYMGMT) operation. 104 See L<provider-keymgmt(7)> for further details. 105 106 =head2 Context Management Functions 107 108 OSSL_FUNC_asym_cipher_newctx() should create and return a pointer to a provider side 109 structure for holding context information during an asymmetric cipher operation. 110 A pointer to this context will be passed back in a number of the other 111 asymmetric cipher operation function calls. 112 The parameter I<provctx> is the provider context generated during provider 113 initialisation (see L<provider(7)>). 114 115 OSSL_FUNC_asym_cipher_freectx() is passed a pointer to the provider side asymmetric 116 cipher context in the I<ctx> parameter. 117 This function should free any resources associated with that context. 118 119 OSSL_FUNC_asym_cipher_dupctx() should duplicate the provider side asymmetric cipher 120 context in the I<ctx> parameter and return the duplicate copy. 121 122 =head2 Encryption Functions 123 124 OSSL_FUNC_asym_cipher_encrypt_init() initialises a context for an asymmetric encryption 125 given a provider side asymmetric cipher context in the I<ctx> parameter, and a 126 pointer to a provider key object in the I<provkey> parameter. 127 The I<params>, if not NULL, should be set on the context in a manner similar to 128 using OSSL_FUNC_asym_cipher_set_ctx_params(). 129 The key object should have been previously generated, loaded or imported into 130 the provider using the key management (OSSL_OP_KEYMGMT) operation (see L<provider-keymgmt(7)>). 131 OSSL_FUNC_asym_cipher_encrypt() performs the actual encryption itself. 132 A previously initialised asymmetric cipher context is passed in the I<ctx> 133 parameter. 134 The data to be encrypted is pointed to by the I<in> parameter which is I<inlen> 135 bytes long. 136 Unless I<out> is NULL, the encrypted data should be written to the location 137 pointed to by the I<out> parameter and it should not exceed I<outsize> bytes in 138 length. 139 The length of the encrypted data should be written to I<*outlen>. 140 If I<out> is NULL then the maximum length of the encrypted data should be 141 written to I<*outlen>. 142 143 =head2 Decryption Functions 144 145 OSSL_FUNC_asym_cipher_decrypt_init() initialises a context for an asymmetric decryption 146 given a provider side asymmetric cipher context in the I<ctx> parameter, and a 147 pointer to a provider key object in the I<provkey> parameter. 148 The I<params>, if not NULL, should be set on the context in a manner similar to 149 using OSSL_FUNC_asym_cipher_set_ctx_params(). 150 The key object should have been previously generated, loaded or imported into 151 the provider using the key management (OSSL_OP_KEYMGMT) operation (see 152 L<provider-keymgmt(7)>). 153 154 OSSL_FUNC_asym_cipher_decrypt() performs the actual decryption itself. 155 A previously initialised asymmetric cipher context is passed in the I<ctx> 156 parameter. 157 The data to be decrypted is pointed to by the I<in> parameter which is I<inlen> 158 bytes long. 159 Unless I<out> is NULL, the decrypted data should be written to the location 160 pointed to by the I<out> parameter and it should not exceed I<outsize> bytes in 161 length. 162 The length of the decrypted data should be written to I<*outlen>. 163 If I<out> is NULL then the maximum length of the decrypted data should be 164 written to I<*outlen>. 165 166 =head2 Asymmetric Cipher Parameters 167 168 See L<OSSL_PARAM(3)> for further details on the parameters structure used by 169 the OSSL_FUNC_asym_cipher_get_ctx_params() and OSSL_FUNC_asym_cipher_set_ctx_params() 170 functions. 171 172 OSSL_FUNC_asym_cipher_get_ctx_params() gets asymmetric cipher parameters associated 173 with the given provider side asymmetric cipher context I<ctx> and stores them in 174 I<params>. 175 Passing NULL for I<params> should return true. 176 177 OSSL_FUNC_asym_cipher_set_ctx_params() sets the asymmetric cipher parameters associated 178 with the given provider side asymmetric cipher context I<ctx> to I<params>. 179 Any parameter settings are additional to any that were previously set. 180 Passing NULL for I<params> should return true. 181 182 Parameters currently recognised by built-in asymmetric cipher algorithms are as 183 follows. 184 Not all parameters are relevant to, or are understood by all asymmetric cipher 185 algorithms: 186 187 =over 4 188 189 =item "pad-mode" (B<OSSL_ASYM_CIPHER_PARAM_PAD_MODE>) <UTF8 string> OR <integer> 190 191 The type of padding to be used. The interpretation of this value will depend 192 on the algorithm in use. 193 194 =item "digest" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST>) <UTF8 string> 195 196 Gets or sets the name of the OAEP digest algorithm used when OAEP padding is in 197 use. 198 199 =item "digest" (B<OSSL_ASYM_CIPHER_PARAM_DIGEST>) <UTF8 string> 200 201 Gets or sets the name of the digest algorithm used by the algorithm (where 202 applicable). 203 204 =item "digest-props" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST_PROPS>) <UTF8 string> 205 206 Gets or sets the properties to use when fetching the OAEP digest algorithm. 207 208 =item "digest-props" (B<OSSL_ASYM_CIPHER_PARAM_DIGEST_PROPS>) <UTF8 string> 209 210 Gets or sets the properties to use when fetching the cipher digest algorithm. 211 212 =item "mgf1-digest" (B<OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST>) <UTF8 string> 213 214 Gets or sets the name of the MGF1 digest algorithm used when OAEP or PSS padding 215 is in use. 216 217 =item "mgf1-digest-props" (B<OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST_PROPS>) <UTF8 string> 218 219 Gets or sets the properties to use when fetching the MGF1 digest algorithm. 220 221 =item "oaep-label" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL>) <octet string ptr> 222 223 Gets the OAEP label used when OAEP padding is in use. 224 225 =item "oaep-label" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL>) <octet string> 226 227 Sets the OAEP label used when OAEP padding is in use. 228 229 =item "tls-client-version" (B<OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION>) <unsigned integer> 230 231 The TLS protocol version first requested by the client. 232 233 =item "tls-negotiated-version" (B<OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION>) <unsigned integer> 234 235 The negotiated TLS protocol version. 236 237 =item "implicit-rejection" (B<OSSL_ASYM_CIPHER_PARAM_IMPLICIT_REJECTION>) <unsigned integer> 238 239 Gets or sets the use of the implicit rejection mechanism for RSA PKCS#1 v1.5 240 decryption. When set (non zero value), the decryption API will return 241 a deterministically random value if the PKCS#1 v1.5 padding check fails. 242 This makes exploitation of the Bleichenbacher significantly harder, even 243 if the code using the RSA decryption API is not implemented in side-channel 244 free manner. Set by default in OpenSSL providers. 245 246 =back 247 248 The OpenSSL FIPS provider also supports the following parameters: 249 250 =over 4 251 252 =item "fips-indicator" (B<OSSL_ASYM_CIPHER_PARAM_FIPS_APPROVED_INDICATOR>) <integer> 253 254 A getter that returns 1 if the operation is FIPS approved, or 0 otherwise. 255 This may be used after calling either OSSL_FUNC_asym_cipher_encrypt() or 256 OSSL_FUNC_asym_cipher_decrypt(). It may return 0 if "key-check" is set to 0. 257 258 =item "key-check" (B<OSSL_ASYM_CIPHER_PARAM_FIPS_KEY_CHECK>) <integer> 259 260 If required this parameter should be set using either 261 OSSL_FUNC_asym_cipher_encrypt_init() or OSSL_FUNC_asym_cipher_decrypt_init(). 262 The default value of 1 causes an error during the init if the key is not FIPS 263 approved (e.g. The key has a security strength of less than 112 bits). Setting 264 this to 0 will ignore the error and set the approved "fips-indicator" to 0. 265 This option breaks FIPS compliance if it causes the approved "fips-indicator" 266 to return 0. 267 268 =back 269 270 OSSL_FUNC_asym_cipher_gettable_ctx_params() and OSSL_FUNC_asym_cipher_settable_ctx_params() 271 get a constant L<OSSL_PARAM(3)> array that describes the gettable and settable 272 parameters, i.e. parameters that can be used with OSSL_FUNC_asym_cipherget_ctx_params() 273 and OSSL_FUNC_asym_cipher_set_ctx_params() respectively. 274 275 =head1 RETURN VALUES 276 277 OSSL_FUNC_asym_cipher_newctx() and OSSL_FUNC_asym_cipher_dupctx() should return the newly 278 created provider side asymmetric cipher context, or NULL on failure. 279 280 All other functions should return 1 for success or 0 on error. 281 282 =head1 SEE ALSO 283 284 L<provider(7)> 285 286 =head1 HISTORY 287 288 The provider ASYM_CIPHER interface was introduced in OpenSSL 3.0. 289 The Asymmetric Cipher Parameters "fips-indicator" and "key-check" 290 were added in OpenSSL 3.4. 291 292 =head1 COPYRIGHT 293 294 Copyright 2019-2026 The OpenSSL Project Authors. All Rights Reserved. 295 296 Licensed under the Apache License 2.0 (the "License"). You may not use 297 this file except in compliance with the License. You can obtain a copy 298 in the file LICENSE in the source distribution or at 299 L<https://www.openssl.org/source/license.html>. 300 301 =cut 302
Indexes created Sat Oct 10 00:27:21 UTC 2026