xref: /openssl/doc/man3/EVP_CIPHER_meth_new.pod (revision 7ed6de99) 
1=pod
2
3=head1 NAME
4
5EVP_CIPHER_meth_new, EVP_CIPHER_meth_dup, EVP_CIPHER_meth_free,
6EVP_CIPHER_meth_set_iv_length, EVP_CIPHER_meth_set_flags,
7EVP_CIPHER_meth_set_impl_ctx_size, EVP_CIPHER_meth_set_init,
8EVP_CIPHER_meth_set_do_cipher, EVP_CIPHER_meth_set_cleanup,
9EVP_CIPHER_meth_set_set_asn1_params, EVP_CIPHER_meth_set_get_asn1_params,
10EVP_CIPHER_meth_set_ctrl, EVP_CIPHER_meth_get_init,
11EVP_CIPHER_meth_get_do_cipher, EVP_CIPHER_meth_get_cleanup,
12EVP_CIPHER_meth_get_set_asn1_params, EVP_CIPHER_meth_get_get_asn1_params,
13EVP_CIPHER_meth_get_ctrl
14- Routines to build up EVP_CIPHER methods
15
16=head1 SYNOPSIS
17
18 #include <openssl/evp.h>
19
20The following functions have been deprecated since OpenSSL 3.0, and can be
21hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
22see L<openssl_user_macros(7)>:
23
24 EVP_CIPHER *EVP_CIPHER_meth_new(int cipher_type, int block_size, int key_len);
25 EVP_CIPHER *EVP_CIPHER_meth_dup(const EVP_CIPHER *cipher);
26 void EVP_CIPHER_meth_free(EVP_CIPHER *cipher);
27
28 int EVP_CIPHER_meth_set_iv_length(EVP_CIPHER *cipher, int iv_len);
29 int EVP_CIPHER_meth_set_flags(EVP_CIPHER *cipher, unsigned long flags);
30 int EVP_CIPHER_meth_set_impl_ctx_size(EVP_CIPHER *cipher, int ctx_size);
31 int EVP_CIPHER_meth_set_init(EVP_CIPHER *cipher,
32                              int (*init)(EVP_CIPHER_CTX *ctx,
33                                          const unsigned char *key,
34                                          const unsigned char *iv,
35                                          int enc));
36 int EVP_CIPHER_meth_set_do_cipher(EVP_CIPHER *cipher,
37                                   int (*do_cipher)(EVP_CIPHER_CTX *ctx,
38                                                    unsigned char *out,
39                                                    const unsigned char *in,
40                                                    size_t inl));
41 int EVP_CIPHER_meth_set_cleanup(EVP_CIPHER *cipher,
42                                 int (*cleanup)(EVP_CIPHER_CTX *));
43 int EVP_CIPHER_meth_set_set_asn1_params(EVP_CIPHER *cipher,
44                                         int (*set_asn1_parameters)(EVP_CIPHER_CTX *,
45                                                                    ASN1_TYPE *));
46 int EVP_CIPHER_meth_set_get_asn1_params(EVP_CIPHER *cipher,
47                                         int (*get_asn1_parameters)(EVP_CIPHER_CTX *,
48                                                                    ASN1_TYPE *));
49 int EVP_CIPHER_meth_set_ctrl(EVP_CIPHER *cipher,
50                              int (*ctrl)(EVP_CIPHER_CTX *, int type,
51                                          int arg, void *ptr));
52
53 int (*EVP_CIPHER_meth_get_init(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *ctx,
54                                                           const unsigned char *key,
55                                                           const unsigned char *iv,
56                                                           int enc);
57 int (*EVP_CIPHER_meth_get_do_cipher(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *ctx,
58                                                                unsigned char *out,
59                                                                const unsigned char *in,
60                                                                size_t inl);
61 int (*EVP_CIPHER_meth_get_cleanup(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *);
62 int (*EVP_CIPHER_meth_get_set_asn1_params(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *,
63                                                                      ASN1_TYPE *);
64 int (*EVP_CIPHER_meth_get_get_asn1_params(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *,
65                                                                      ASN1_TYPE *);
66 int (*EVP_CIPHER_meth_get_ctrl(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *,
67                                                           int type, int arg,
68                                                           void *ptr);
69
70=head1 DESCRIPTION
71
72All of the functions described on this page are deprecated.
73Applications should instead use the OSSL_PROVIDER APIs.
74
75The B<EVP_CIPHER> type is a structure for symmetric cipher method
76implementation.
77
78EVP_CIPHER_meth_new() creates a new B<EVP_CIPHER> structure.
79
80EVP_CIPHER_meth_dup() creates a copy of B<cipher>.
81
82EVP_CIPHER_meth_free() destroys a B<EVP_CIPHER> structure.
83If the argument is NULL, nothing is done.
84
85EVP_CIPHER_meth_set_iv_length() sets the length of the IV.
86This is only needed when the implemented cipher mode requires it.
87
88EVP_CIPHER_meth_set_flags() sets the flags to describe optional
89behaviours in the particular B<cipher>.
90With the exception of cipher modes, of which only one may be present,
91several flags can be or'd together.
92The available flags are:
93
94=over 4
95
96=item EVP_CIPH_STREAM_CIPHER, EVP_CIPH_ECB_MODE EVP_CIPH_CBC_MODE,
97EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE, EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE,
98EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE, EVP_CIPH_WRAP_MODE,
99EVP_CIPH_OCB_MODE, EVP_CIPH_SIV_MODE
100
101The cipher mode.
102
103=item EVP_CIPH_VARIABLE_LENGTH
104
105This cipher is of variable length.
106
107=item EVP_CIPH_CUSTOM_IV
108
109Storing and initialising the IV is left entirely to the
110implementation.
111
112=item EVP_CIPH_ALWAYS_CALL_INIT
113
114Set this if the implementation's init() function should be called even
115if B<key> is B<NULL>.
116
117=item EVP_CIPH_CTRL_INIT
118
119Set this to have the implementation's ctrl() function called with
120command code B<EVP_CTRL_INIT> early in its setup.
121
122=item EVP_CIPH_CUSTOM_KEY_LENGTH
123
124Checking and setting the key length after creating the B<EVP_CIPHER>
125is left to the implementation.
126Whenever someone uses EVP_CIPHER_CTX_set_key_length() on a
127B<EVP_CIPHER> with this flag set, the implementation's ctrl() function
128will be called with the control code B<EVP_CTRL_SET_KEY_LENGTH> and
129the key length in B<arg>.
130
131=item EVP_CIPH_NO_PADDING
132
133Don't use standard block padding.
134
135=item EVP_CIPH_RAND_KEY
136
137Making a key with random content is left to the implementation.
138This is done by calling the implementation's ctrl() function with the
139control code B<EVP_CTRL_RAND_KEY> and the pointer to the key memory
140storage in B<ptr>.
141
142=item EVP_CIPH_CUSTOM_COPY
143
144Set this to have the implementation's ctrl() function called with
145command code B<EVP_CTRL_COPY> at the end of EVP_CIPHER_CTX_copy().
146The intended use is for further things to deal with after the
147implementation specific data block has been copied.
148The destination B<EVP_CIPHER_CTX> is passed to the control with the
149B<ptr> parameter.
150The implementation specific data block is reached with
151EVP_CIPHER_CTX_get_cipher_data().
152
153=item EVP_CIPH_FLAG_DEFAULT_ASN1
154
155Use the default EVP routines to pass IV to and from ASN.1.
156
157=item EVP_CIPH_FLAG_LENGTH_BITS
158
159Signals that the length of the input buffer for encryption /
160decryption is to be understood as the number of bits instead of
161bytes for this implementation.
162This is only useful for CFB1 ciphers.
163
164=item EVP_CIPH_FLAG_CTS
165
166Indicates that the cipher uses ciphertext stealing. This is currently
167used to indicate that the cipher is a one shot that only allows a single call to
168EVP_CipherUpdate().
169
170=item EVP_CIPH_FLAG_CUSTOM_CIPHER
171
172This indicates that the implementation takes care of everything,
173including padding, buffering and finalization.
174The EVP routines will simply give them control and do nothing more.
175
176=item EVP_CIPH_FLAG_AEAD_CIPHER
177
178This indicates that this is an AEAD cipher implementation.
179
180=item EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK
181
182Allow interleaving of crypto blocks, a particular optimization only applicable
183to certain TLS ciphers.
184
185=back
186
187EVP_CIPHER_meth_set_impl_ctx_size() sets the size of the EVP_CIPHER's
188implementation context so that it can be automatically allocated.
189
190EVP_CIPHER_meth_set_init() sets the cipher init function for
191B<cipher>.
192The cipher init function is called by EVP_CipherInit(),
193EVP_CipherInit_ex(), EVP_EncryptInit(), EVP_EncryptInit_ex(),
194EVP_DecryptInit(), EVP_DecryptInit_ex().
195
196EVP_CIPHER_meth_set_do_cipher() sets the cipher function for
197B<cipher>.
198The cipher function is called by EVP_CipherUpdate(),
199EVP_EncryptUpdate(), EVP_DecryptUpdate(), EVP_CipherFinal(),
200EVP_EncryptFinal(), EVP_EncryptFinal_ex(), EVP_DecryptFinal() and
201EVP_DecryptFinal_ex().
202
203EVP_CIPHER_meth_set_cleanup() sets the function for B<cipher> to do
204extra cleanup before the method's private data structure is cleaned
205out and freed.
206Note that the cleanup function is passed a B<EVP_CIPHER_CTX *>, the
207private data structure is then available with
208EVP_CIPHER_CTX_get_cipher_data().
209This cleanup function is called by EVP_CIPHER_CTX_reset() and
210EVP_CIPHER_CTX_free().
211
212EVP_CIPHER_meth_set_set_asn1_params() sets the function for B<cipher>
213to set the AlgorithmIdentifier "parameter" based on the passed cipher.
214This function is called by EVP_CIPHER_param_to_asn1().
215EVP_CIPHER_meth_set_get_asn1_params() sets the function for B<cipher>
216that sets the cipher parameters based on an ASN.1 AlgorithmIdentifier
217"parameter".
218Both these functions are needed when there is a need for custom data
219(more or other than the cipher IV).
220They are called by EVP_CIPHER_param_to_asn1() and
221EVP_CIPHER_asn1_to_param() respectively if defined.
222
223EVP_CIPHER_meth_set_ctrl() sets the control function for B<cipher>.
224
225EVP_CIPHER_meth_get_init(), EVP_CIPHER_meth_get_do_cipher(),
226EVP_CIPHER_meth_get_cleanup(), EVP_CIPHER_meth_get_set_asn1_params(),
227EVP_CIPHER_meth_get_get_asn1_params() and EVP_CIPHER_meth_get_ctrl()
228are all used to retrieve the method data given with the
229EVP_CIPHER_meth_set_*() functions above.
230
231=head1 RETURN VALUES
232
233EVP_CIPHER_meth_new() and EVP_CIPHER_meth_dup() return a pointer to a
234newly created B<EVP_CIPHER>, or NULL on failure.
235All EVP_CIPHER_meth_set_*() functions return 1.
236All EVP_CIPHER_meth_get_*() functions return pointers to their
237respective B<cipher> function.
238
239=head1 SEE ALSO
240
241L<EVP_EncryptInit(3)>
242
243=head1 HISTORY
244
245All of these functions were deprecated in OpenSSL 3.0.
246
247The functions described here were added in OpenSSL 1.1.0.
248The B<EVP_CIPHER> structure created with these functions became reference
249counted in OpenSSL 3.0.
250
251=head1 COPYRIGHT
252
253Copyright 2016-2024 The OpenSSL Project Authors. All Rights Reserved.
254
255Licensed under the Apache License 2.0 (the "License").  You may not use
256this file except in compliance with the License.  You can obtain a copy
257in the file LICENSE in the source distribution or at
258L<https://www.openssl.org/source/license.html>.
259
260=cut
261