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 int OSSL_FUNC_asym_cipher_encrypt(void *ctx, unsigned char *out, size_t *outlen,
28 size_t outsize, const unsigned char *in,
32 int OSSL_FUNC_asym_cipher_decrypt_init(void *ctx, void *provkey);
33 int OSSL_FUNC_asym_cipher_decrypt(void *ctx, unsigned char *out, size_t *outlen,
34 size_t outsize, const unsigned char *in,
37 /* Asymmetric Cipher parameters */
38 int OSSL_FUNC_asym_cipher_get_ctx_params(void *ctx, OSSL_PARAM params[]);
39 const OSSL_PARAM *OSSL_FUNC_asym_cipher_gettable_ctx_params(void *provctx);
40 int OSSL_FUNC_asym_cipher_set_ctx_params(void *ctx, const OSSL_PARAM params[]);
41 const OSSL_PARAM *OSSL_FUNC_asym_cipher_settable_ctx_params(void *provctx);
45 This documentation is primarily aimed at provider authors. See L<provider(7)>
46 for further information.
48 The asymmetric cipher (OSSL_OP_ASYM_CIPHER) operation enables providers to
49 implement asymmetric cipher algorithms and make them available to applications
50 via the API functions L<EVP_PKEY_encrypt(3)>,
51 L<EVP_PKEY_decrypt(3)> and
52 other related functions).
54 All "functions" mentioned here are passed as function pointers between
55 F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays via
56 B<OSSL_ALGORITHM> arrays that are returned by the provider's
57 provider_query_operation() function
58 (see L<provider-base(7)/Provider Functions>).
60 All these "functions" have a corresponding function type definition
61 named B<OSSL_{name}_fn>, and a helper function to retrieve the
62 function pointer from an B<OSSL_DISPATCH> element named
64 For example, the "function" OSSL_FUNC_asym_cipher_newctx() has these:
66 typedef void *(OSSL_FUNC_asym_cipher_newctx_fn)(void *provctx);
67 static ossl_inline OSSL_FUNC_asym_cipher_newctx_fn
68 OSSL_FUNC_asym_cipher_newctx(const OSSL_DISPATCH *opf);
70 B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
71 macros in L<openssl-core_dispatch.h(7)>, as follows:
73 OSSL_FUNC_asym_cipher_newctx OSSL_FUNC_ASYM_CIPHER_NEWCTX
74 OSSL_FUNC_asym_cipher_freectx OSSL_FUNC_ASYM_CIPHER_FREECTX
75 OSSL_FUNC_asym_cipher_dupctx OSSL_FUNC_ASYM_CIPHER_DUPCTX
77 OSSL_FUNC_asym_cipher_encrypt_init OSSL_FUNC_ASYM_CIPHER_ENCRYPT_INIT
78 OSSL_FUNC_asym_cipher_encrypt OSSL_FUNC_ASYM_CIPHER_ENCRYPT
80 OSSL_FUNC_asym_cipher_decrypt_init OSSL_FUNC_ASYM_CIPHER_DECRYPT_INIT
81 OSSL_FUNC_asym_cipher_decrypt OSSL_FUNC_ASYM_CIPHER_DECRYPT
83 OSSL_FUNC_asym_cipher_get_ctx_params OSSL_FUNC_ASYM_CIPHER_GET_CTX_PARAMS
84 OSSL_FUNC_asym_cipher_gettable_ctx_params OSSL_FUNC_ASYM_CIPHER_GETTABLE_CTX_PARAMS
85 OSSL_FUNC_asym_cipher_set_ctx_params OSSL_FUNC_ASYM_CIPHER_SET_CTX_PARAMS
86 OSSL_FUNC_asym_cipher_settable_ctx_params OSSL_FUNC_ASYM_CIPHER_SETTABLE_CTX_PARAMS
88 An asymmetric cipher algorithm implementation may not implement all of these
90 In order to be a consistent set of functions a provider must implement
91 OSSL_FUNC_asym_cipher_newctx and OSSL_FUNC_asym_cipher_freectx.
92 It must also implement both of OSSL_FUNC_asym_cipher_encrypt_init and
93 OSSL_FUNC_asym_cipher_encrypt, or both of OSSL_FUNC_asym_cipher_decrypt_init and
94 OSSL_FUNC_asym_cipher_decrypt.
95 OSSL_FUNC_asym_cipher_get_ctx_params is optional but if it is present then so must
96 OSSL_FUNC_asym_cipher_gettable_ctx_params.
97 Similarly, OSSL_FUNC_asym_cipher_set_ctx_params is optional but if it is present then
98 so must OSSL_FUNC_asym_cipher_settable_ctx_params.
100 An asymmetric cipher algorithm must also implement some mechanism for generating,
101 loading or importing keys via the key management (OSSL_OP_KEYMGMT) operation.
102 See L<provider-keymgmt(7)> for further details.
104 =head2 Context Management Functions
106 OSSL_FUNC_asym_cipher_newctx() should create and return a pointer to a provider side
107 structure for holding context information during an asymmetric cipher operation.
108 A pointer to this context will be passed back in a number of the other
109 asymmetric cipher operation function calls.
110 The parameter I<provctx> is the provider context generated during provider
111 initialisation (see L<provider(7)>).
113 OSSL_FUNC_asym_cipher_freectx() is passed a pointer to the provider side asymmetric
114 cipher context in the I<ctx> parameter.
115 This function should free any resources associated with that context.
117 OSSL_FUNC_asym_cipher_dupctx() should duplicate the provider side asymmetric cipher
118 context in the I<ctx> parameter and return the duplicate copy.
120 =head2 Encryption Functions
122 OSSL_FUNC_asym_cipher_encrypt_init() initialises a context for an asymmetric encryption
123 given a provider side asymmetric cipher context in the I<ctx> parameter, and a
124 pointer to a provider key object in the I<provkey> parameter.
125 The key object should have been previously generated, loaded or imported into
126 the provider using the key management (OSSL_OP_KEYMGMT) operation (see
127 provider-keymgmt(7)>.
129 OSSL_FUNC_asym_cipher_encrypt() performs the actual encryption itself.
130 A previously initialised asymmetric cipher context is passed in the I<ctx>
132 The data to be encrypted is pointed to by the I<in> parameter which is I<inlen>
134 Unless I<out> is NULL, the encrypted data should be written to the location
135 pointed to by the I<out> parameter and it should not exceed I<outsize> bytes in
137 The length of the encrypted data should be written to I<*outlen>.
138 If I<out> is NULL then the maximum length of the encrypted data should be
139 written to I<*outlen>.
141 =head2 Decryption Functions
143 OSSL_FUNC_asym_cipher_decrypt_init() initialises a context for an asymmetric decryption
144 given a provider side asymmetric cipher context in the I<ctx> parameter, and a
145 pointer to a provider key object in the I<provkey> parameter.
146 The key object should have been previously generated, loaded or imported into
147 the provider using the key management (OSSL_OP_KEYMGMT) operation (see
148 provider-keymgmt(7)>.
150 OSSL_FUNC_asym_cipher_decrypt() performs the actual decryption itself.
151 A previously initialised asymmetric cipher context is passed in the I<ctx>
153 The data to be decrypted is pointed to by the I<in> parameter which is I<inlen>
155 Unless I<out> is NULL, the decrypted data should be written to the location
156 pointed to by the I<out> parameter and it should not exceed I<outsize> bytes in
158 The length of the decrypted data should be written to I<*outlen>.
159 If I<out> is NULL then the maximum length of the decrypted data should be
160 written to I<*outlen>.
162 =head2 Asymmetric Cipher Parameters
164 See L<OSSL_PARAM(3)> for further details on the parameters structure used by
165 the OSSL_FUNC_asym_cipher_get_ctx_params() and OSSL_FUNC_asym_cipher_set_ctx_params()
168 OSSL_FUNC_asym_cipher_get_ctx_params() gets asymmetric cipher parameters associated
169 with the given provider side asymmetric cipher context I<ctx> and stores them in
171 OSSL_FUNC_asym_cipher_set_ctx_params() sets the asymmetric cipher parameters associated
172 with the given provider side asymmetric cipher context I<ctx> to I<params>.
173 Any parameter settings are additional to any that were previously set.
175 Parameters currently recognised by built-in asymmetric cipher algorithms are as
177 Not all parameters are relevant to, or are understood by all asymmetric cipher
182 =item "pad-mode" (B<OSSL_ASYM_CIPHER_PARAM_PAD_MODE>) <integer>
184 The type of padding to be used. The interpretation of this value will depend
185 on the algorithm in use. The default provider understands these RSA padding
186 modes: 1 (RSA_PKCS1_PADDING), 2 (RSA_SSLV23_PADDING), 3 (RSA_NO_PADDING),
187 4 (RSA_PKCS1_OAEP_PADDING), 5 (RSA_X931_PADDING), 6 (RSA_PKCS1_PSS_PADDING) and
188 7 (RSA_PKCS1_WITH_TLS_PADDING). See L<EVP_PKEY_CTX_set_rsa_padding(3)> for
191 =item "digest" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST>) <UTF8 string>
193 Gets or sets the name of the OAEP digest algorithm used when OAEP padding is in
196 =item "digest" (B<OSSL_ASYM_CIPHER_PARAM_DIGEST>) <UTF8 string>
198 Gets or sets the name of the digest algorithm used by the algorithm (where
201 =item "digest-props" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST_PROPS>) <UTF8 string>
203 Gets or sets the properties to use when fetching the OAEP digest algorithm.
205 =item "digest-props" (B<OSSL_ASYM_CIPHER_PARAM_DIGEST_PROPS>) <UTF8 string>
207 Gets or sets the properties to use when fetching the cipher digest algorithm.
209 =item "mgf1-digest" (B<OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST>) <UTF8 string>
211 Gets or sets the name of the MGF1 digest algorithm used when OAEP or PSS padding
214 =item "mgf1-digest-props" (B<OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST_PROPS>) <UTF8 string>
216 Gets or sets the properties to use when fetching the MGF1 digest algorithm.
218 =item "oaep-label" (B<OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL>) <octet string>
220 Gets or sets the OAEP label used when OAEP padding is in use.
222 =item "tls-client-version" (B<OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION>) <unsigned integer>
224 The TLS protocol version first requested by the client. See
225 B<RSA_PKCS1_WITH_TLS_PADDING> on the page L<EVP_PKEY_CTX_set_rsa_padding(3)>.
227 =item "tls-negotiated-version" (B<OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION>) <unsigned integer>
229 The negotiated TLS protocol version. See
230 B<RSA_PKCS1_WITH_TLS_PADDING> on the page L<EVP_PKEY_CTX_set_rsa_padding(3)>.
234 OSSL_FUNC_asym_cipher_gettable_ctx_params() and OSSL_FUNC_asym_cipher_settable_ctx_params()
235 get a constant B<OSSL_PARAM> array that describes the gettable and settable
236 parameters, i.e. parameters that can be used with OSSL_FUNC_asym_cipherget_ctx_params()
237 and OSSL_FUNC_asym_cipher_set_ctx_params() respectively.
238 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
242 OSSL_FUNC_asym_cipher_newctx() and OSSL_FUNC_asym_cipher_dupctx() should return the newly
243 created provider side asymmetric cipher context, or NULL on failure.
245 All other functions should return 1 for success or 0 on error.
253 The provider ASYM_CIPHER interface was introduced in OpenSSL 3.0.
257 Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
259 Licensed under the Apache License 2.0 (the "License"). You may not use
260 this file except in compliance with the License. You can obtain a copy
261 in the file LICENSE in the source distribution or at
262 L<https://www.openssl.org/source/license.html>.