1=pod 2 3=head1 NAME 4 5provider-cipher - The 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_cipher_newctx(void *provctx); 22 void OSSL_FUNC_cipher_freectx(void *cctx); 23 void *OSSL_FUNC_cipher_dupctx(void *cctx); 24 25 /* Encryption/decryption */ 26 int OSSL_FUNC_cipher_encrypt_init(void *cctx, const unsigned char *key, 27 size_t keylen, const unsigned char *iv, 28 size_t ivlen, const OSSL_PARAM params[]); 29 int OSSL_FUNC_cipher_decrypt_init(void *cctx, const unsigned char *key, 30 size_t keylen, const unsigned char *iv, 31 size_t ivlen, const OSSL_PARAM params[]); 32 int OSSL_FUNC_cipher_update(void *cctx, unsigned char *out, size_t *outl, 33 size_t outsize, const unsigned char *in, size_t inl); 34 int OSSL_FUNC_cipher_final(void *cctx, unsigned char *out, size_t *outl, 35 size_t outsize); 36 int OSSL_FUNC_cipher_cipher(void *cctx, unsigned char *out, size_t *outl, 37 size_t outsize, const unsigned char *in, size_t inl); 38 39 /* Cipher parameter descriptors */ 40 const OSSL_PARAM *OSSL_FUNC_cipher_gettable_params(void *provctx); 41 42 /* Cipher operation parameter descriptors */ 43 const OSSL_PARAM *OSSL_FUNC_cipher_gettable_ctx_params(void *cctx, 44 void *provctx); 45 const OSSL_PARAM *OSSL_FUNC_cipher_settable_ctx_params(void *cctx, 46 void *provctx); 47 48 /* Cipher parameters */ 49 int OSSL_FUNC_cipher_get_params(OSSL_PARAM params[]); 50 51 /* Cipher operation parameters */ 52 int OSSL_FUNC_cipher_get_ctx_params(void *cctx, OSSL_PARAM params[]); 53 int OSSL_FUNC_cipher_set_ctx_params(void *cctx, const OSSL_PARAM params[]); 54 55=head1 DESCRIPTION 56 57This documentation is primarily aimed at provider authors. See L<provider(7)> 58for further information. 59 60The CIPHER operation enables providers to implement cipher algorithms and make 61them available to applications via the API functions L<EVP_EncryptInit_ex(3)>, 62L<EVP_EncryptUpdate(3)> and L<EVP_EncryptFinal(3)> (as well as the decrypt 63equivalents and other related functions). 64 65All "functions" mentioned here are passed as function pointers between 66F<libcrypto> and the provider in L<OSSL_DISPATCH(3)> arrays via 67L<OSSL_ALGORITHM(3)> arrays that are returned by the provider's 68provider_query_operation() function 69(see L<provider-base(7)/Provider Functions>). 70 71All these "functions" have a corresponding function type definition 72named B<OSSL_FUNC_{name}_fn>, and a helper function to retrieve the 73function pointer from an L<OSSL_DISPATCH(3)> element named 74B<OSSL_FUNC_{name}>. 75For example, the "function" OSSL_FUNC_cipher_newctx() has these: 76 77 typedef void *(OSSL_FUNC_cipher_newctx_fn)(void *provctx); 78 static ossl_inline OSSL_FUNC_cipher_newctx_fn 79 OSSL_FUNC_cipher_newctx(const OSSL_DISPATCH *opf); 80 81L<OSSL_DISPATCH(3)> arrays are indexed by numbers that are provided as 82macros in L<openssl-core_dispatch.h(7)>, as follows: 83 84 OSSL_FUNC_cipher_newctx OSSL_FUNC_CIPHER_NEWCTX 85 OSSL_FUNC_cipher_freectx OSSL_FUNC_CIPHER_FREECTX 86 OSSL_FUNC_cipher_dupctx OSSL_FUNC_CIPHER_DUPCTX 87 88 OSSL_FUNC_cipher_encrypt_init OSSL_FUNC_CIPHER_ENCRYPT_INIT 89 OSSL_FUNC_cipher_decrypt_init OSSL_FUNC_CIPHER_DECRYPT_INIT 90 OSSL_FUNC_cipher_update OSSL_FUNC_CIPHER_UPDATE 91 OSSL_FUNC_cipher_final OSSL_FUNC_CIPHER_FINAL 92 OSSL_FUNC_cipher_cipher OSSL_FUNC_CIPHER_CIPHER 93 94 OSSL_FUNC_cipher_get_params OSSL_FUNC_CIPHER_GET_PARAMS 95 OSSL_FUNC_cipher_get_ctx_params OSSL_FUNC_CIPHER_GET_CTX_PARAMS 96 OSSL_FUNC_cipher_set_ctx_params OSSL_FUNC_CIPHER_SET_CTX_PARAMS 97 98 OSSL_FUNC_cipher_gettable_params OSSL_FUNC_CIPHER_GETTABLE_PARAMS 99 OSSL_FUNC_cipher_gettable_ctx_params OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS 100 OSSL_FUNC_cipher_settable_ctx_params OSSL_FUNC_CIPHER_SETTABLE_CTX_PARAMS 101 102A cipher algorithm implementation may not implement all of these functions. 103In order to be a consistent set of functions there must at least be a complete 104set of "encrypt" functions, or a complete set of "decrypt" functions, or a 105single "cipher" function. 106In all cases both the OSSL_FUNC_cipher_newctx and OSSL_FUNC_cipher_freectx functions must be 107present. 108All other functions are optional. 109 110=head2 Context Management Functions 111 112OSSL_FUNC_cipher_newctx() should create and return a pointer to a provider side 113structure for holding context information during a cipher operation. 114A pointer to this context will be passed back in a number of the other cipher 115operation function calls. 116The parameter I<provctx> is the provider context generated during provider 117initialisation (see L<provider(7)>). 118 119OSSL_FUNC_cipher_freectx() is passed a pointer to the provider side cipher context in 120the I<cctx> parameter. 121This function should free any resources associated with that context. 122 123OSSL_FUNC_cipher_dupctx() should duplicate the provider side cipher context in the 124I<cctx> parameter and return the duplicate copy. 125 126=head2 Encryption/Decryption Functions 127 128OSSL_FUNC_cipher_encrypt_init() initialises a cipher operation for encryption given a 129newly created provider side cipher context in the I<cctx> parameter. 130The key to be used is given in I<key> which is I<keylen> bytes long. 131The IV to be used is given in I<iv> which is I<ivlen> bytes long. 132The I<params>, if not NULL, should be set on the context in a manner similar to 133using OSSL_FUNC_cipher_set_ctx_params(). 134 135OSSL_FUNC_cipher_decrypt_init() is the same as OSSL_FUNC_cipher_encrypt_init() except that it 136initialises the context for a decryption operation. 137 138OSSL_FUNC_cipher_update() is called to supply data to be encrypted/decrypted as part of 139a previously initialised cipher operation. 140The I<cctx> parameter contains a pointer to a previously initialised provider 141side context. 142OSSL_FUNC_cipher_update() should encrypt/decrypt I<inl> bytes of data at the location 143pointed to by I<in>. 144The encrypted data should be stored in I<out> and the amount of data written to 145I<*outl> which should not exceed I<outsize> bytes. 146OSSL_FUNC_cipher_update() may be called multiple times for a single cipher operation. 147It is the responsibility of the cipher implementation to handle input lengths 148that are not multiples of the block length. 149In such cases a cipher implementation will typically cache partial blocks of 150input data until a complete block is obtained. 151The pointers I<out> and I<in> may point to the same location, in which 152case the encryption must be done in-place. If I<out> and I<in> point to different 153locations, the requirements of L<EVP_EncryptUpdate(3)> and L<EVP_DecryptUpdate(3)> 154guarantee that the two buffers are disjoint. 155Similarly, the requirements of L<EVP_EncryptUpdate(3)> and L<EVP_DecryptUpdate(3)> 156ensure that the buffer pointed to by I<out> contains sufficient room for the 157operation being performed. 158 159OSSL_FUNC_cipher_final() completes an encryption or decryption started through previous 160OSSL_FUNC_cipher_encrypt_init() or OSSL_FUNC_cipher_decrypt_init(), and OSSL_FUNC_cipher_update() 161calls. 162The I<cctx> parameter contains a pointer to the provider side context. 163Any final encryption/decryption output should be written to I<out> and the 164amount of data written to I<*outl> which should not exceed I<outsize> bytes. 165The same expectations apply to I<outsize> as documented for 166L<EVP_EncryptFinal(3)> and L<EVP_DecryptFinal(3)>. 167 168OSSL_FUNC_cipher_cipher() performs encryption/decryption using the provider side cipher 169context in the I<cctx> parameter that should have been previously initialised via 170a call to OSSL_FUNC_cipher_encrypt_init() or OSSL_FUNC_cipher_decrypt_init(). 171This should call the raw underlying cipher function without any padding. 172This will be invoked in the provider as a result of the application calling 173L<EVP_Cipher(3)>. 174The application is responsible for ensuring that the input is a multiple of the 175block length. 176The data to be encrypted/decrypted will be in I<in>, and it will be I<inl> bytes 177in length. 178The output from the encryption/decryption should be stored in I<out> and the 179amount of data stored should be put in I<*outl> which should be no more than 180I<outsize> bytes. 181 182=head2 Cipher Parameters 183 184See L<OSSL_PARAM(3)> for further details on the parameters structure used by 185these functions. 186 187OSSL_FUNC_cipher_get_params() gets details of the algorithm implementation 188and stores them in I<params>. 189 190OSSL_FUNC_cipher_set_ctx_params() sets cipher operation parameters for the 191provider side cipher context I<cctx> to I<params>. 192Any parameter settings are additional to any that were previously set. 193Passing NULL for I<params> should return true. 194 195OSSL_FUNC_cipher_get_ctx_params() gets cipher operation details details from 196the given provider side cipher context I<cctx> and stores them in I<params>. 197Passing NULL for I<params> should return true. 198 199OSSL_FUNC_cipher_gettable_params(), OSSL_FUNC_cipher_gettable_ctx_params(), 200and OSSL_FUNC_cipher_settable_ctx_params() all return constant L<OSSL_PARAM(3)> 201arrays as descriptors of the parameters that OSSL_FUNC_cipher_get_params(), 202OSSL_FUNC_cipher_get_ctx_params(), and OSSL_FUNC_cipher_set_ctx_params() 203can handle, respectively. OSSL_FUNC_cipher_gettable_ctx_params() and 204OSSL_FUNC_cipher_settable_ctx_params() will return the parameters associated 205with the provider side context I<cctx> in its current state if it is 206not NULL. Otherwise, they return the parameters associated with the 207provider side algorithm I<provctx>. 208 209Parameters currently recognised by built-in ciphers are listed in 210L<EVP_EncryptInit(3)/PARAMETERS>. 211Not all parameters are relevant to, or are understood by all ciphers. 212 213=head1 RETURN VALUES 214 215OSSL_FUNC_cipher_newctx() and OSSL_FUNC_cipher_dupctx() should return the newly created 216provider side cipher context, or NULL on failure. 217 218OSSL_FUNC_cipher_encrypt_init(), OSSL_FUNC_cipher_decrypt_init(), OSSL_FUNC_cipher_update(), 219OSSL_FUNC_cipher_final(), OSSL_FUNC_cipher_cipher(), OSSL_FUNC_cipher_get_params(), 220OSSL_FUNC_cipher_get_ctx_params() and OSSL_FUNC_cipher_set_ctx_params() should return 1 for 221success or 0 on error. 222 223OSSL_FUNC_cipher_gettable_params(), OSSL_FUNC_cipher_gettable_ctx_params() and 224OSSL_FUNC_cipher_settable_ctx_params() should return a constant L<OSSL_PARAM(3)> 225array, or NULL if none is offered. 226 227=head1 SEE ALSO 228 229L<provider(7)>, L<OSSL_PROVIDER-FIPS(7)>, L<OSSL_PROVIDER-default(7)>, 230L<OSSL_PROVIDER-legacy(7)>, 231L<EVP_CIPHER-AES(7)>, L<EVP_CIPHER-ARIA(7)>, L<EVP_CIPHER-BLOWFISH(7)>, 232L<EVP_CIPHER-CAMELLIA(7)>, L<EVP_CIPHER-CAST(7)>, L<EVP_CIPHER-CHACHA(7)>, 233L<EVP_CIPHER-DES(7)>, L<EVP_CIPHER-IDEA(7)>, L<EVP_CIPHER-RC2(7)>, 234L<EVP_CIPHER-RC4(7)>, L<EVP_CIPHER-RC5(7)>, L<EVP_CIPHER-SEED(7)>, 235L<EVP_CIPHER-SM4(7)>, L<EVP_CIPHER-NULL(7)>, 236L<life_cycle-cipher(7)>, L<EVP_EncryptInit(3)> 237 238=head1 HISTORY 239 240The provider CIPHER interface was introduced in OpenSSL 3.0. 241 242=head1 COPYRIGHT 243 244Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved. 245 246Licensed under the Apache License 2.0 (the "License"). You may not use 247this file except in compliance with the License. You can obtain a copy 248in the file LICENSE in the source distribution or at 249L<https://www.openssl.org/source/license.html>. 250 251=cut 252