5 provider-asym_cipher - The asym_cipher library E<lt>-E<gt> provider functions
9 =for openssl multiple includes
11 #include <openssl/core_dispatch.h>
12 #include <openssl/core_names.h>
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.
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);
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,
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,
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 *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 *provctx);
47 This documentation is primarily aimed at provider authors. See L<provider(7)>
48 for further information.
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).
56 All "functions" mentioned here are passed as function pointers between
57 F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays via
58 B<OSSL_ALGORITHM> arrays that are returned by the provider's
59 provider_query_operation() function
60 (see L<provider-base(7)/Provider Functions>).
62 All these "functions" have a corresponding function type definition
63 named B<OSSL_{name}_fn>, and a helper function to retrieve the
64 function pointer from an B<OSSL_DISPATCH> element named
66 For example, the "function" OSSL_FUNC_asym_cipher_newctx() has these:
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);
72 B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
73 macros in L<openssl-core_dispatch.h(7)>, as follows:
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
79 OSSL_FUNC_asym_cipher_encrypt_init OSSL_FUNC_ASYM_CIPHER_ENCRYPT_INIT
80 OSSL_FUNC_asym_cipher_encrypt OSSL_FUNC_ASYM_CIPHER_ENCRYPT
82 OSSL_FUNC_asym_cipher_decrypt_init OSSL_FUNC_ASYM_CIPHER_DECRYPT_INIT
83 OSSL_FUNC_asym_cipher_decrypt OSSL_FUNC_ASYM_CIPHER_DECRYPT
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
90 An asymmetric cipher algorithm implementation may not implement all of these
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.
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.
106 =head2 Context Management Functions
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)>).
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.
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.
122 =head2 Encryption Functions
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
131 provider-keymgmt(7)>.
132 OSSL_FUNC_asym_cipher_encrypt() performs the actual encryption itself.
133 A previously initialised asymmetric cipher context is passed in the I<ctx>
135 The data to be encrypted is pointed to by the I<in> parameter which is I<inlen>
137 Unless I<out> is NULL, the encrypted data should be written to the location
138 pointed to by the I<out> parameter and it should not exceed I<outsize> bytes in
140 The length of the encrypted data should be written to I<*outlen>.
141 If I<out> is NULL then the maximum length of the encrypted data should be
142 written to I<*outlen>.
144 =head2 Decryption Functions
146 OSSL_FUNC_asym_cipher_decrypt_init() initialises a context for an asymmetric decryption
147 given a provider side asymmetric cipher context in the I<ctx> parameter, and a
148 pointer to a provider key object in the I<provkey> parameter.
149 The I<params>, if not NULL, should be set on the context in a manner similar to
150 using OSSL_FUNC_asym_cipher_set_ctx_params().
151 The key object should have been previously generated, loaded or imported into
152 the provider using the key management (OSSL_OP_KEYMGMT) operation (see
153 provider-keymgmt(7)>.
155 OSSL_FUNC_asym_cipher_decrypt() performs the actual decryption itself.
156 A previously initialised asymmetric cipher context is passed in the I<ctx>
158 The data to be decrypted is pointed to by the I<in> parameter which is I<inlen>
160 Unless I<out> is NULL, the decrypted data should be written to the location
161 pointed to by the I<out> parameter and it should not exceed I<outsize> bytes in
163 The length of the decrypted data should be written to I<*outlen>.
164 If I<out> is NULL then the maximum length of the decrypted data should be
165 written to I<*outlen>.
167 =head2 Asymmetric Cipher Parameters
169 See L<OSSL_PARAM(3)> for further details on the parameters structure used by
170 the OSSL_FUNC_asym_cipher_get_ctx_params() and OSSL_FUNC_asym_cipher_set_ctx_params()
173 OSSL_FUNC_asym_cipher_get_ctx_params() gets asymmetric cipher parameters associated
174 with the given provider side asymmetric cipher context I<ctx> and stores them in
176 Passing NULL for I<params> should return true.
178 OSSL_FUNC_asym_cipher_set_ctx_params() sets the asymmetric cipher parameters associated
179 with the given provider side asymmetric cipher context I<ctx> to I<params>.
180 Any parameter settings are additional to any that were previously set.
181 Passing NULL for I<params> should return true.
183 Parameters currently recognised by built-in asymmetric cipher algorithms are as
185 Not all parameters are relevant to, or are understood by all asymmetric cipher
190 =item "pad-mode" (B<OSSL_ASYM_CIPHER_PARAM_PAD_MODE>) <integer>
192 The type of padding to be used. The interpretation of this value will depend
193 on the algorithm in use. The default provider understands these RSA padding
194 modes: 1 (RSA_PKCS1_PADDING), 3 (RSA_NO_PADDING),
195 4 (RSA_PKCS1_OAEP_PADDING), 5 (RSA_X931_PADDING), 6 (RSA_PKCS1_PSS_PADDING) and
196 7 (RSA_PKCS1_WITH_TLS_PADDING). See L<EVP_PKEY_CTX_set_rsa_padding(3)> for
199 =item "digest" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST>) <UTF8 string>
201 Gets or sets the name of the OAEP digest algorithm used when OAEP padding is in
204 =item "digest" (B<OSSL_ASYM_CIPHER_PARAM_DIGEST>) <UTF8 string>
206 Gets or sets the name of the digest algorithm used by the algorithm (where
209 =item "digest-props" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST_PROPS>) <UTF8 string>
211 Gets or sets the properties to use when fetching the OAEP digest algorithm.
213 =item "digest-props" (B<OSSL_ASYM_CIPHER_PARAM_DIGEST_PROPS>) <UTF8 string>
215 Gets or sets the properties to use when fetching the cipher digest algorithm.
217 =item "mgf1-digest" (B<OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST>) <UTF8 string>
219 Gets or sets the name of the MGF1 digest algorithm used when OAEP or PSS padding
222 =item "mgf1-digest-props" (B<OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST_PROPS>) <UTF8 string>
224 Gets or sets the properties to use when fetching the MGF1 digest algorithm.
226 =item "oaep-label" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL>) <octet string>
228 Gets or sets the OAEP label used when OAEP padding is in use.
230 =item "tls-client-version" (B<OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION>) <unsigned integer>
232 The TLS protocol version first requested by the client. See
233 B<RSA_PKCS1_WITH_TLS_PADDING> on the page L<EVP_PKEY_CTX_set_rsa_padding(3)>.
235 =item "tls-negotiated-version" (B<OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION>) <unsigned integer>
237 The negotiated TLS protocol version. See
238 B<RSA_PKCS1_WITH_TLS_PADDING> on the page L<EVP_PKEY_CTX_set_rsa_padding(3)>.
242 OSSL_FUNC_asym_cipher_gettable_ctx_params() and OSSL_FUNC_asym_cipher_settable_ctx_params()
243 get a constant B<OSSL_PARAM> array that describes the gettable and settable
244 parameters, i.e. parameters that can be used with OSSL_FUNC_asym_cipherget_ctx_params()
245 and OSSL_FUNC_asym_cipher_set_ctx_params() respectively.
246 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
250 OSSL_FUNC_asym_cipher_newctx() and OSSL_FUNC_asym_cipher_dupctx() should return the newly
251 created provider side asymmetric cipher context, or NULL on failure.
253 All other functions should return 1 for success or 0 on error.
261 The provider ASYM_CIPHER interface was introduced in OpenSSL 3.0.
265 Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
267 Licensed under the Apache License 2.0 (the "License"). You may not use
268 this file except in compliance with the License. You can obtain a copy
269 in the file LICENSE in the source distribution or at
270 L<https://www.openssl.org/source/license.html>.