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 - Routines to build up EVP_CIPHER methods
14
15=head1 SYNOPSIS
16
17 #include <openssl/evp.h>
18
19 EVP_CIPHER *EVP_CIPHER_meth_new(int cipher_type, int block_size, int key_len);
20 EVP_CIPHER *EVP_CIPHER_meth_dup(const EVP_CIPHER *cipher);
21 void EVP_CIPHER_meth_free(EVP_CIPHER *cipher);
22
23 int EVP_CIPHER_meth_set_iv_length(EVP_CIPHER *cipher, int iv_len);
24 int EVP_CIPHER_meth_set_flags(EVP_CIPHER *cipher, unsigned long flags);
25 int EVP_CIPHER_meth_set_impl_ctx_size(EVP_CIPHER *cipher, int ctx_size);
26 int EVP_CIPHER_meth_set_init(EVP_CIPHER *cipher,
27                              int (*init)(EVP_CIPHER_CTX *ctx,
28                                          const unsigned char *key,
29                                          const unsigned char *iv,
30                                          int enc));
31 int EVP_CIPHER_meth_set_do_cipher(EVP_CIPHER *cipher,
32                                   int (*do_cipher)(EVP_CIPHER_CTX *ctx,
33                                                    unsigned char *out,
34                                                    const unsigned char *in,
35                                                    size_t inl));
36 int EVP_CIPHER_meth_set_cleanup(EVP_CIPHER *cipher,
37                                 int (*cleanup)(EVP_CIPHER_CTX *));
38 int EVP_CIPHER_meth_set_set_asn1_params(EVP_CIPHER *cipher,
39                                         int (*set_asn1_parameters)(EVP_CIPHER_CTX *,
40                                                                    ASN1_TYPE *));
41 int EVP_CIPHER_meth_set_get_asn1_params(EVP_CIPHER *cipher,
42                                         int (*get_asn1_parameters)(EVP_CIPHER_CTX *,
43                                                                    ASN1_TYPE *));
44 int EVP_CIPHER_meth_set_ctrl(EVP_CIPHER *cipher,
45                              int (*ctrl)(EVP_CIPHER_CTX *, int type,
46                                          int arg, void *ptr));
47
48 int (*EVP_CIPHER_meth_get_init(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *ctx,
49                                                           const unsigned char *key,
50                                                           const unsigned char *iv,
51                                                           int enc);
52 int (*EVP_CIPHER_meth_get_do_cipher(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *ctx,
53                                                                unsigned char *out,
54                                                                const unsigned char *in,
55                                                                size_t inl);
56 int (*EVP_CIPHER_meth_get_cleanup(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *);
57 int (*EVP_CIPHER_meth_get_set_asn1_params(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *,
58                                                                      ASN1_TYPE *);
59 int (*EVP_CIPHER_meth_get_get_asn1_params(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *,
60                                                                      ASN1_TYPE *);
61 int (*EVP_CIPHER_meth_get_ctrl(const EVP_CIPHER *cipher))(EVP_CIPHER_CTX *,
62                                                           int type, int arg,
63                                                           void *ptr);
64
65=head1 DESCRIPTION
66
67The B<EVP_CIPHER> type is a structure for symmetric cipher method
68implementation.
69
70EVP_CIPHER_meth_new() creates a new B<EVP_CIPHER> structure.
71
72EVP_CIPHER_meth_dup() creates a copy of B<cipher>.
73
74EVP_CIPHER_meth_free() destroys a B<EVP_CIPHER> structure.
75
76EVP_CIPHER_meth_set_iv_length() sets the length of the IV.
77This is only needed when the implemented cipher mode requires it.
78
79EVP_CIPHER_meth_set_flags() sets the flags to describe optional
80behaviours in the particular B<cipher>.
81With the exception of cipher modes, of which only one may be present,
82several flags can be or'd together.
83The available flags are:
84
85=over 4
86
87=item EVP_CIPH_STREAM_CIPHER, EVP_CIPH_ECB_MODE EVP_CIPH_CBC_MODE,
88EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE, EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE,
89EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE, EVP_CIPH_WRAP_MODE,
90EVP_CIPH_OCB_MODE
91
92The cipher mode.
93
94=item EVP_CIPH_VARIABLE_LENGTH
95
96This cipher is of variable length.
97
98=item EVP_CIPH_CUSTOM_IV
99
100Storing and initialising the IV is left entirely to the
101implementation.
102
103=item EVP_CIPH_ALWAYS_CALL_INIT
104
105Set this if the implementation's init() function should be called even
106if B<key> is B<NULL>.
107
108=item EVP_CIPH_CTRL_INIT
109
110Set this to have the implementation's ctrl() function called with
111command code B<EVP_CTRL_INIT> early in its setup.
112
113=item EVP_CIPH_CUSTOM_KEY_LENGTH
114
115Checking and setting the key length after creating the B<EVP_CIPHER>
116is left to the implementation.
117Whenever someone uses EVP_CIPHER_CTX_set_key_length() on a
118B<EVP_CIPHER> with this flag set, the implementation's ctrl() function
119will be called with the control code B<EVP_CTRL_SET_KEY_LENGTH> and
120the key length in B<arg>.
121
122=item EVP_CIPH_NO_PADDING
123
124Don't use standard block padding.
125
126=item EVP_CIPH_RAND_KEY
127
128Making a key with random content is left to the implementation.
129This is done by calling the implementation's ctrl() function with the
130control code B<EVP_CTRL_RAND_KEY> and the pointer to the key memory
131storage in B<ptr>.
132
133=item EVP_CIPH_CUSTOM_COPY
134
135Set this to have the implementation's ctrl() function called with
136command code B<EVP_CTRL_COPY> at the end of EVP_CIPHER_CTX_copy().
137The intended use is for further things to deal with after the
138implementation specific data block has been copied.
139The destination B<EVP_CIPHER_CTX> is passed to the control with the
140B<ptr> parameter.
141The implementation specific data block is reached with
142EVP_CIPHER_CTX_get_cipher_data().
143
144=item EVP_CIPH_FLAG_DEFAULT_ASN1
145
146Use the default EVP routines to pass IV to and from ASN.1.
147
148=item EVP_CIPH_FLAG_LENGTH_BITS
149
150Signals that the length of the input buffer for encryption /
151decryption is to be understood as the number of bits instead of
152bytes for this implementation.
153This is only useful for CFB1 ciphers.
154
155=begin comment
156The FIPS flags seem to be unused, so I'm hiding them until I get an
157explanation or they get removed.  /RL
158
159=item EVP_CIPH_FLAG_FIPS
160
161=item EVP_CIPH_FLAG_NON_FIPS_ALLOW
162
163=end comment
164
165=item EVP_CIPH_FLAG_CUSTOM_CIPHER
166
167This indicates that the implementation takes care of everything,
168including padding, buffering and finalization.
169The EVP routines will simply give them control and do nothing more.
170
171=item EVP_CIPH_FLAG_AEAD_CIPHER
172
173This indicates that this is an AEAD cipher implementation.
174
175=item EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK
176
177Allow interleaving of crypto blocks, a particular optimization only applicable
178to certain TLS ciphers.
179
180=back
181
182EVP_CIPHER_meth_set_impl_ctx_size() sets the size of the EVP_CIPHER's
183implementation context so that it can be automatically allocated.
184
185EVP_CIPHER_meth_set_init() sets the cipher init function for
186B<cipher>.
187The cipher init function is called by EVP_CipherInit(),
188EVP_CipherInit_ex(), EVP_EncryptInit(), EVP_EncryptInit_ex(),
189EVP_DecryptInit(), EVP_DecryptInit_ex().
190
191EVP_CIPHER_meth_set_do_cipher() sets the cipher function for
192B<cipher>.
193The cipher function is called by EVP_CipherUpdate(),
194EVP_EncryptUpdate(), EVP_DecryptUpdate(), EVP_CipherFinal(),
195EVP_EncryptFinal(), EVP_EncryptFinal_ex(), EVP_DecryptFinal() and
196EVP_DecryptFinal_ex().
197
198EVP_CIPHER_meth_set_cleanup() sets the function for B<cipher> to do
199extra cleanup before the method's private data structure is cleaned
200out and freed.
201Note that the cleanup function is passed a B<EVP_CIPHER_CTX *>, the
202private data structure is then available with
203EVP_CIPHER_CTX_get_cipher_data().
204This cleanup function is called by EVP_CIPHER_CTX_reset() and
205EVP_CIPHER_CTX_free().
206
207EVP_CIPHER_meth_set_set_asn1_params() sets the function for B<cipher>
208to set the AlgorithmIdentifier "parameter" based on the passed cipher.
209This function is called by EVP_CIPHER_param_to_asn1().
210EVP_CIPHER_meth_set_get_asn1_params() sets the function for B<cipher>
211that sets the cipher parameters based on an ASN.1 AlgorithmIdentifier
212"parameter".
213Both these functions are needed when there is a need for custom data
214(more or other than the cipher IV).
215They are called by EVP_CIPHER_param_to_asn1() and
216EVP_CIPHER_asn1_to_param() respectively if defined.
217
218EVP_CIPHER_meth_set_ctrl() sets the control function for B<cipher>.
219
220EVP_CIPHER_meth_get_init(), EVP_CIPHER_meth_get_do_cipher(),
221EVP_CIPHER_meth_get_cleanup(), EVP_CIPHER_meth_get_set_asn1_params(),
222EVP_CIPHER_meth_get_get_asn1_params() and EVP_CIPHER_meth_get_ctrl()
223are all used to retrieve the method data given with the
224EVP_CIPHER_meth_set_*() functions above.
225
226=head1 RETURN VALUES
227
228EVP_CIPHER_meth_new() and EVP_CIPHER_meth_dup() return a pointer to a
229newly created B<EVP_CIPHER>, or NULL on failure.
230All EVP_CIPHER_meth_set_*() functions return 1.
231All EVP_CIPHER_meth_get_*() functions return pointers to their
232respective B<cipher> function.
233
234=head1 SEE ALSO
235
236L<EVP_EncryptInit>
237
238=head1 HISTORY
239
240The functions described here were added in OpenSSL 1.1.0.
241
242=head1 COPYRIGHT
243
244Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
245
246Licensed under the OpenSSL license (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