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Commit | Line | Data |
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72b60351 DSH |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
2cafb1df | 5 | EVP_CIPHER_fetch, |
550f974a RL |
6 | EVP_CIPHER_up_ref, |
7 | EVP_CIPHER_free, | |
8fa4d95e RT |
8 | EVP_CIPHER_CTX_new, |
9 | EVP_CIPHER_CTX_reset, | |
10 | EVP_CIPHER_CTX_free, | |
11 | EVP_EncryptInit_ex, | |
12 | EVP_EncryptUpdate, | |
13 | EVP_EncryptFinal_ex, | |
14 | EVP_DecryptInit_ex, | |
15 | EVP_DecryptUpdate, | |
16 | EVP_DecryptFinal_ex, | |
17 | EVP_CipherInit_ex, | |
18 | EVP_CipherUpdate, | |
19 | EVP_CipherFinal_ex, | |
20 | EVP_CIPHER_CTX_set_key_length, | |
21 | EVP_CIPHER_CTX_ctrl, | |
22 | EVP_EncryptInit, | |
23 | EVP_EncryptFinal, | |
24 | EVP_DecryptInit, | |
25 | EVP_DecryptFinal, | |
26 | EVP_CipherInit, | |
27 | EVP_CipherFinal, | |
f7397f0d | 28 | EVP_Cipher, |
8fa4d95e RT |
29 | EVP_get_cipherbyname, |
30 | EVP_get_cipherbynid, | |
31 | EVP_get_cipherbyobj, | |
7cfa1717 | 32 | EVP_CIPHER_is_a, |
c750bc08 | 33 | EVP_CIPHER_name, |
506cb0f6 | 34 | EVP_CIPHER_number, |
f651c727 | 35 | EVP_CIPHER_names_do_all, |
1d2622d4 | 36 | EVP_CIPHER_provider, |
8fa4d95e | 37 | EVP_CIPHER_nid, |
ae3ff60e RL |
38 | EVP_CIPHER_get_params, |
39 | EVP_CIPHER_gettable_params, | |
8fa4d95e RT |
40 | EVP_CIPHER_block_size, |
41 | EVP_CIPHER_key_length, | |
42 | EVP_CIPHER_iv_length, | |
43 | EVP_CIPHER_flags, | |
44 | EVP_CIPHER_mode, | |
45 | EVP_CIPHER_type, | |
46 | EVP_CIPHER_CTX_cipher, | |
c750bc08 | 47 | EVP_CIPHER_CTX_name, |
8fa4d95e | 48 | EVP_CIPHER_CTX_nid, |
ae3ff60e | 49 | EVP_CIPHER_CTX_get_params, |
41f7ecf3 | 50 | EVP_CIPHER_gettable_ctx_params, |
ae3ff60e | 51 | EVP_CIPHER_CTX_set_params, |
41f7ecf3 | 52 | EVP_CIPHER_settable_ctx_params, |
8fa4d95e RT |
53 | EVP_CIPHER_CTX_block_size, |
54 | EVP_CIPHER_CTX_key_length, | |
55 | EVP_CIPHER_CTX_iv_length, | |
dc64dc2e | 56 | EVP_CIPHER_CTX_tag_length, |
8fa4d95e RT |
57 | EVP_CIPHER_CTX_get_app_data, |
58 | EVP_CIPHER_CTX_set_app_data, | |
59 | EVP_CIPHER_CTX_type, | |
60 | EVP_CIPHER_CTX_flags, | |
61 | EVP_CIPHER_CTX_mode, | |
62 | EVP_CIPHER_param_to_asn1, | |
63 | EVP_CIPHER_asn1_to_param, | |
64 | EVP_CIPHER_CTX_set_padding, | |
c540f00f | 65 | EVP_enc_null, |
251e610c | 66 | EVP_CIPHER_do_all_provided |
8fa4d95e | 67 | - EVP cipher routines |
72b60351 DSH |
68 | |
69 | =head1 SYNOPSIS | |
70 | ||
bb82531f | 71 | =for openssl generic |
b97fdb57 | 72 | |
72b60351 DSH |
73 | #include <openssl/evp.h> |
74 | ||
2cafb1df RL |
75 | EVP_CIPHER *EVP_CIPHER_fetch(OPENSSL_CTX *ctx, const char *algorithm, |
76 | const char *properties); | |
550f974a RL |
77 | int EVP_CIPHER_up_ref(EVP_CIPHER *cipher); |
78 | void EVP_CIPHER_free(EVP_CIPHER *cipher); | |
05fdb8d3 RL |
79 | EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void); |
80 | int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx); | |
81 | void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx); | |
3811eed8 DSH |
82 | |
83 | int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 84 | ENGINE *impl, const unsigned char *key, const unsigned char *iv); |
a91dedca | 85 | int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
7bbb0050 | 86 | int *outl, const unsigned char *in, int inl); |
e9b77246 | 87 | int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl); |
3811eed8 DSH |
88 | |
89 | int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 90 | ENGINE *impl, const unsigned char *key, const unsigned char *iv); |
3811eed8 | 91 | int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
7bbb0050 | 92 | int *outl, const unsigned char *in, int inl); |
e9b77246 | 93 | int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
3811eed8 DSH |
94 | |
95 | int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 96 | ENGINE *impl, const unsigned char *key, const unsigned char *iv, int enc); |
3811eed8 | 97 | int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
b38fa985 | 98 | int *outl, const unsigned char *in, int inl); |
e9b77246 | 99 | int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
3811eed8 DSH |
100 | |
101 | int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 102 | const unsigned char *key, const unsigned char *iv); |
e9b77246 | 103 | int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl); |
4d524e10 | 104 | |
a91dedca | 105 | int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, |
b38fa985 | 106 | const unsigned char *key, const unsigned char *iv); |
e9b77246 | 107 | int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
4d524e10 | 108 | |
a91dedca | 109 | int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, |
b38fa985 | 110 | const unsigned char *key, const unsigned char *iv, int enc); |
e9b77246 | 111 | int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
72b60351 | 112 | |
f7397f0d RL |
113 | int EVP_Cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, |
114 | const unsigned char *in, unsigned int inl); | |
115 | ||
f2e5ca84 | 116 | int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding); |
a91dedca DSH |
117 | int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen); |
118 | int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr); | |
5c5eb286 | 119 | int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key); |
72b60351 DSH |
120 | |
121 | const EVP_CIPHER *EVP_get_cipherbyname(const char *name); | |
91da5e77 RS |
122 | const EVP_CIPHER *EVP_get_cipherbynid(int nid); |
123 | const EVP_CIPHER *EVP_get_cipherbyobj(const ASN1_OBJECT *a); | |
124 | ||
125 | int EVP_CIPHER_nid(const EVP_CIPHER *e); | |
506cb0f6 | 126 | int EVP_CIPHER_number(const EVP_CIPHER *e); |
7cfa1717 | 127 | int EVP_CIPHER_is_a(const EVP_CIPHER *cipher, const char *name); |
f651c727 RL |
128 | void EVP_CIPHER_names_do_all(const EVP_CIPHER *cipher, |
129 | void (*fn)(const char *name, void *data), | |
130 | void *data); | |
c750bc08 | 131 | const char *EVP_CIPHER_name(const EVP_CIPHER *cipher); |
1d2622d4 | 132 | const OSSL_PROVIDER *EVP_CIPHER_provider(const EVP_CIPHER *cipher); |
91da5e77 | 133 | int EVP_CIPHER_block_size(const EVP_CIPHER *e); |
91da5e77 RS |
134 | int EVP_CIPHER_key_length(const EVP_CIPHER *e); |
135 | int EVP_CIPHER_iv_length(const EVP_CIPHER *e); | |
136 | unsigned long EVP_CIPHER_flags(const EVP_CIPHER *e); | |
137 | unsigned long EVP_CIPHER_mode(const EVP_CIPHER *e); | |
72b60351 | 138 | int EVP_CIPHER_type(const EVP_CIPHER *ctx); |
a91dedca | 139 | |
05fdb8d3 RL |
140 | const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *ctx); |
141 | int EVP_CIPHER_CTX_nid(const EVP_CIPHER_CTX *ctx); | |
c750bc08 | 142 | const char *EVP_CIPHER_CTX_name(const EVP_CIPHER_CTX *ctx); |
ae3ff60e RL |
143 | |
144 | int EVP_CIPHER_get_params(EVP_CIPHER *cipher, OSSL_PARAM params[]); | |
145 | int EVP_CIPHER_CTX_set_params(EVP_CIPHER_CTX *ctx, const OSSL_PARAM params[]); | |
146 | int EVP_CIPHER_CTX_get_params(EVP_CIPHER_CTX *ctx, OSSL_PARAM params[]); | |
147 | const OSSL_PARAM *EVP_CIPHER_gettable_params(const EVP_CIPHER *cipher); | |
41f7ecf3 P |
148 | const OSSL_PARAM *EVP_CIPHER_settable_ctx_params(const EVP_CIPHER *cipher); |
149 | const OSSL_PARAM *EVP_CIPHER_gettable_ctx_params(const EVP_CIPHER *cipher); | |
05fdb8d3 RL |
150 | int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *ctx); |
151 | int EVP_CIPHER_CTX_key_length(const EVP_CIPHER_CTX *ctx); | |
152 | int EVP_CIPHER_CTX_iv_length(const EVP_CIPHER_CTX *ctx); | |
dc64dc2e | 153 | int EVP_CIPHER_CTX_tag_length(const EVP_CIPHER_CTX *ctx); |
05fdb8d3 RL |
154 | void *EVP_CIPHER_CTX_get_app_data(const EVP_CIPHER_CTX *ctx); |
155 | void EVP_CIPHER_CTX_set_app_data(const EVP_CIPHER_CTX *ctx, void *data); | |
156 | int EVP_CIPHER_CTX_type(const EVP_CIPHER_CTX *ctx); | |
05fdb8d3 | 157 | int EVP_CIPHER_CTX_mode(const EVP_CIPHER_CTX *ctx); |
72b60351 | 158 | |
3f2b5a88 DSH |
159 | int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type); |
160 | int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type); | |
161 | ||
251e610c RL |
162 | void EVP_CIPHER_do_all_provided(OPENSSL_CTX *libctx, |
163 | void (*fn)(EVP_CIPHER *cipher, void *arg), | |
164 | void *arg); | |
c540f00f | 165 | |
72b60351 DSH |
166 | =head1 DESCRIPTION |
167 | ||
168 | The EVP cipher routines are a high level interface to certain | |
169 | symmetric ciphers. | |
170 | ||
550f974a RL |
171 | The B<EVP_CIPHER> type is a structure for cipher method implementation. |
172 | ||
2cafb1df RL |
173 | EVP_CIPHER_fetch() fetches the cipher implementation for the given |
174 | B<algorithm> from any provider offering it, within the criteria given | |
175 | by the B<properties>. | |
176 | See L<provider(7)/Fetching algorithms> for further information. | |
177 | ||
550f974a RL |
178 | The returned value must eventually be freed with EVP_CIPHER_free(). |
179 | ||
180 | EVP_CIPHER_up_ref() increments the reference count for an B<EVP_CIPHER> | |
181 | structure. | |
182 | ||
183 | EVP_CIPHER_free() decrements the reference count for the B<EVP_CIPHER> | |
184 | structure. | |
185 | If the reference count drops to 0 then the structure is freed. | |
2cafb1df | 186 | |
05fdb8d3 RL |
187 | EVP_CIPHER_CTX_new() creates a cipher context. |
188 | ||
189 | EVP_CIPHER_CTX_free() clears all information from a cipher context | |
190 | and free up any allocated memory associate with it, including B<ctx> | |
191 | itself. This function should be called after all operations using a | |
192 | cipher are complete so sensitive information does not remain in | |
193 | memory. | |
3811eed8 DSH |
194 | |
195 | EVP_EncryptInit_ex() sets up cipher context B<ctx> for encryption | |
2cafb1df RL |
196 | with cipher B<type>. B<type> is typically supplied by a function such |
197 | as EVP_aes_256_cbc(), or a value explicitly fetched with | |
198 | EVP_CIPHER_fetch(). If B<impl> is non-NULL, its implementation of the | |
199 | cipher B<type> is used if there is one, and if not, the default | |
200 | implementation is used. B<key> is the symmetric key to use | |
3811eed8 DSH |
201 | and B<iv> is the IV to use (if necessary), the actual number of bytes |
202 | used for the key and IV depends on the cipher. It is possible to set | |
203 | all parameters to NULL except B<type> in an initial call and supply | |
204 | the remaining parameters in subsequent calls, all of which have B<type> | |
205 | set to NULL. This is done when the default cipher parameters are not | |
206 | appropriate. | |
a672a02a SL |
207 | For EVP_CIPH_GCM_MODE the IV will be generated internally if it is not |
208 | specified. | |
72b60351 DSH |
209 | |
210 | EVP_EncryptUpdate() encrypts B<inl> bytes from the buffer B<in> and | |
211 | writes the encrypted version to B<out>. This function can be called | |
212 | multiple times to encrypt successive blocks of data. The amount | |
213 | of data written depends on the block alignment of the encrypted data: | |
214 | as a result the amount of data written may be anything from zero bytes | |
5211e094 | 215 | to (inl + cipher_block_size - 1) so B<out> should contain sufficient |
c3a73daf AP |
216 | room. The actual number of bytes written is placed in B<outl>. It also |
217 | checks if B<in> and B<out> are partially overlapping, and if they are | |
218 | 0 is returned to indicate failure. | |
72b60351 | 219 | |
3811eed8 | 220 | If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts |
f2e5ca84 | 221 | the "final" data, that is any data that remains in a partial block. |
a09474dd RS |
222 | It uses standard block padding (aka PKCS padding) as described in |
223 | the NOTES section, below. The encrypted | |
f2e5ca84 DSH |
224 | final data is written to B<out> which should have sufficient space for |
225 | one cipher block. The number of bytes written is placed in B<outl>. After | |
226 | this function is called the encryption operation is finished and no further | |
227 | calls to EVP_EncryptUpdate() should be made. | |
228 | ||
3811eed8 | 229 | If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more |
f2e5ca84 | 230 | data and it will return an error if any data remains in a partial block: |
c7497f34 | 231 | that is if the total data length is not a multiple of the block size. |
72b60351 | 232 | |
3811eed8 | 233 | EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex() are the |
72b60351 | 234 | corresponding decryption operations. EVP_DecryptFinal() will return an |
f2e5ca84 DSH |
235 | error code if padding is enabled and the final block is not correctly |
236 | formatted. The parameters and restrictions are identical to the encryption | |
237 | operations except that if padding is enabled the decrypted data buffer B<out> | |
238 | passed to EVP_DecryptUpdate() should have sufficient room for | |
239 | (B<inl> + cipher_block_size) bytes unless the cipher block size is 1 in | |
240 | which case B<inl> bytes is sufficient. | |
72b60351 | 241 | |
3811eed8 DSH |
242 | EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex() are |
243 | functions that can be used for decryption or encryption. The operation | |
244 | performed depends on the value of the B<enc> parameter. It should be set | |
245 | to 1 for encryption, 0 for decryption and -1 to leave the value unchanged | |
246 | (the actual value of 'enc' being supplied in a previous call). | |
247 | ||
05fdb8d3 RL |
248 | EVP_CIPHER_CTX_reset() clears all information from a cipher context |
249 | and free up any allocated memory associate with it, except the B<ctx> | |
250 | itself. This function should be called anytime B<ctx> is to be reused | |
251 | for another EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal() | |
252 | series of calls. | |
3811eed8 DSH |
253 | |
254 | EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit() behave in a | |
d4a43700 | 255 | similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and |
b45497c3 | 256 | EVP_CipherInit_ex() except they always use the default cipher implementation. |
72b60351 | 257 | |
538860a3 RS |
258 | EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() are |
259 | identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and | |
260 | EVP_CipherFinal_ex(). In previous releases they also cleaned up | |
261 | the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean() | |
262 | must be called to free any context resources. | |
72b60351 | 263 | |
f7397f0d RL |
264 | EVP_Cipher() encrypts or decrypts a maximum I<inl> amount of bytes from |
265 | I<in> and leaves the result in I<out>. | |
266 | If the cipher doesn't have the flag B<EVP_CIPH_FLAG_CUSTOM_CIPHER> set, | |
267 | then I<inl> must be a multiple of EVP_CIPHER_block_size(). If it isn't, | |
268 | the result is undefined. If the cipher has that flag set, then I<inl> | |
269 | can be any size. | |
270 | This function is historic and shouldn't be used in an application, please | |
271 | consider using EVP_CipherUpdate() and EVP_CipherFinal_ex instead. | |
272 | ||
3f2b5a88 DSH |
273 | EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() |
274 | return an EVP_CIPHER structure when passed a cipher name, a NID or an | |
275 | ASN1_OBJECT structure. | |
276 | ||
277 | EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return the NID of a cipher when | |
278 | passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> structure. The actual NID | |
279 | value is an internal value which may not have a corresponding OBJECT | |
280 | IDENTIFIER. | |
281 | ||
83f68df3 CPLG |
282 | EVP_CIPHER_CTX_set_padding() enables or disables padding. This |
283 | function should be called after the context is set up for encryption | |
284 | or decryption with EVP_EncryptInit_ex(), EVP_DecryptInit_ex() or | |
285 | EVP_CipherInit_ex(). By default encryption operations are padded using | |
286 | standard block padding and the padding is checked and removed when | |
287 | decrypting. If the B<pad> parameter is zero then no padding is | |
288 | performed, the total amount of data encrypted or decrypted must then | |
289 | be a multiple of the block size or an error will occur. | |
f2e5ca84 | 290 | |
ae3ff60e RL |
291 | EVP_CIPHER_get_params() retrieves the requested list of algorithm |
292 | B<params> from a B<cipher>. | |
293 | ||
294 | EVP_CIPHER_CTX_set_params() Sets the list of operation B<params> into a CIPHER | |
295 | context B<ctx>. | |
296 | ||
297 | EVP_CIPHER_CTX_get_params() retrieves the requested list of operation | |
298 | B<params> from CIPHER context B<ctx>. | |
299 | ||
41f7ecf3 P |
300 | EVP_CIPHER_gettable_params(), EVP_CIPHER_gettable_ctx_params(), and |
301 | EVP_CIPHER_settable_ctx_params() get a constant B<OSSL_PARAM> array | |
79c44b4e | 302 | that describes the retrievable and settable parameters, i.e. parameters |
ae3ff60e RL |
303 | that can be used with EVP_CIPHER_get_params(), EVP_CIPHER_CTX_get_params() |
304 | and EVP_CIPHER_CTX_set_params(), respectively. | |
305 | See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor. | |
306 | ||
3f2b5a88 DSH |
307 | EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key |
308 | length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> | |
309 | structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum key length | |
a91dedca DSH |
310 | for all ciphers. Note: although EVP_CIPHER_key_length() is fixed for a |
311 | given cipher, the value of EVP_CIPHER_CTX_key_length() may be different | |
312 | for variable key length ciphers. | |
313 | ||
314 | EVP_CIPHER_CTX_set_key_length() sets the key length of the cipher ctx. | |
315 | If the cipher is a fixed length cipher then attempting to set the key | |
316 | length to any value other than the fixed value is an error. | |
3f2b5a88 DSH |
317 | |
318 | EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV | |
319 | length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>. | |
320 | It will return zero if the cipher does not use an IV. The constant | |
321 | B<EVP_MAX_IV_LENGTH> is the maximum IV length for all ciphers. | |
322 | ||
dc64dc2e SL |
323 | EVP_CIPHER_CTX_tag_length() returns the tag length of a AEAD cipher when passed |
324 | a B<EVP_CIPHER_CTX>. It will return zero if the cipher does not support a tag. | |
325 | It returns a default value if the tag length has not been set. | |
326 | ||
3f2b5a88 DSH |
327 | EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block |
328 | size of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> | |
14f46560 | 329 | structure. The constant B<EVP_MAX_BLOCK_LENGTH> is also the maximum block |
3f2b5a88 DSH |
330 | length for all ciphers. |
331 | ||
332 | EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the type of the passed | |
333 | cipher or context. This "type" is the actual NID of the cipher OBJECT | |
334 | IDENTIFIER as such it ignores the cipher parameters and 40 bit RC2 and | |
41e68ef2 DSH |
335 | 128 bit RC2 have the same NID. If the cipher does not have an object |
336 | identifier or does not have ASN1 support this function will return | |
337 | B<NID_undef>. | |
3f2b5a88 | 338 | |
251e610c | 339 | EVP_CIPHER_is_a() returns 1 if I<cipher> is an implementation of an |
7cfa1717 | 340 | algorithm that's identifiable with I<name>, otherwise 0. |
e4a1d023 RL |
341 | If I<cipher> is a legacy cipher (it's the return value from the likes |
342 | of EVP_aes128() rather than the result of an EVP_CIPHER_fetch()), only | |
343 | cipher names registered with the default library context (see | |
344 | L<OPENSSL_CTX(3)>) will be considered. | |
7cfa1717 | 345 | |
506cb0f6 RL |
346 | EVP_CIPHER_number() returns the internal dynamic number assigned to |
347 | the I<cipher>. This is only useful with fetched B<EVP_CIPHER>s. | |
348 | ||
c750bc08 | 349 | EVP_CIPHER_name() and EVP_CIPHER_CTX_name() return the name of the passed |
251e610c | 350 | cipher or context. For fetched ciphers with multiple names, only one |
f651c727 RL |
351 | of them is returned; it's recommended to use EVP_CIPHER_names_do_all() |
352 | instead. | |
353 | ||
354 | EVP_CIPHER_names_do_all() traverses all names for the I<cipher>, and | |
355 | calls I<fn> with each name and I<data>. This is only useful with | |
356 | fetched B<EVP_CIPHER>s. | |
c750bc08 | 357 | |
1d2622d4 RL |
358 | EVP_CIPHER_provider() returns an B<OSSL_PROVIDER> pointer to the provider |
359 | that implements the given B<EVP_CIPHER>. | |
360 | ||
3f2b5a88 DSH |
361 | EVP_CIPHER_CTX_cipher() returns the B<EVP_CIPHER> structure when passed |
362 | an B<EVP_CIPHER_CTX> structure. | |
363 | ||
a91dedca | 364 | EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return the block cipher mode: |
338ead0f PS |
365 | EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE, |
366 | EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE, | |
11dbdc07 MC |
367 | EVP_CIPH_WRAP_MODE, EVP_CIPH_OCB_MODE or EVP_CIPH_SIV_MODE. If the cipher is a |
368 | stream cipher then EVP_CIPH_STREAM_CIPHER is returned. | |
369 | ||
370 | EVP_CIPHER_flags() returns any flags associated with the cipher. See | |
371 | EVP_CIPHER_meth_set_flags() for a list of currently defined flags. | |
a91dedca | 372 | |
3f2b5a88 DSH |
373 | EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter" based |
374 | on the passed cipher. This will typically include any parameters and an | |
375 | IV. The cipher IV (if any) must be set when this call is made. This call | |
376 | should be made before the cipher is actually "used" (before any | |
377 | EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example). This function | |
378 | may fail if the cipher does not have any ASN1 support. | |
379 | ||
380 | EVP_CIPHER_asn1_to_param() sets the cipher parameters based on an ASN1 | |
381 | AlgorithmIdentifier "parameter". The precise effect depends on the cipher | |
382 | In the case of RC2, for example, it will set the IV and effective key length. | |
383 | This function should be called after the base cipher type is set but before | |
384 | the key is set. For example EVP_CipherInit() will be called with the IV and | |
385 | key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally | |
386 | EVP_CipherInit() again with all parameters except the key set to NULL. It is | |
387 | possible for this function to fail if the cipher does not have any ASN1 support | |
388 | or the parameters cannot be set (for example the RC2 effective key length | |
a91dedca DSH |
389 | is not supported. |
390 | ||
391 | EVP_CIPHER_CTX_ctrl() allows various cipher specific parameters to be determined | |
aa714f3a | 392 | and set. |
3f2b5a88 | 393 | |
5c5eb286 PS |
394 | EVP_CIPHER_CTX_rand_key() generates a random key of the appropriate length |
395 | based on the cipher context. The EVP_CIPHER can provide its own random key | |
396 | generation routine to support keys of a specific form. B<Key> must point to a | |
397 | buffer at least as big as the value returned by EVP_CIPHER_CTX_key_length(). | |
398 | ||
251e610c | 399 | EVP_CIPHER_do_all_provided() traverses all ciphers implemented by all activated |
c540f00f RL |
400 | providers in the given library context I<libctx>, and for each of the |
401 | implementations, calls the given function I<fn> with the implementation method | |
402 | and the given I<arg> as argument. | |
403 | ||
72b60351 DSH |
404 | =head1 RETURN VALUES |
405 | ||
2cafb1df RL |
406 | EVP_CIPHER_fetch() returns a pointer to a B<EVP_CIPHER> for success |
407 | and B<NULL> for failure. | |
408 | ||
550f974a RL |
409 | EVP_CIPHER_up_ref() returns 1 for success or 0 otherwise. |
410 | ||
05fdb8d3 RL |
411 | EVP_CIPHER_CTX_new() returns a pointer to a newly created |
412 | B<EVP_CIPHER_CTX> for success and B<NULL> for failure. | |
413 | ||
0e304b7f NL |
414 | EVP_EncryptInit_ex(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex() |
415 | return 1 for success and 0 for failure. | |
72b60351 | 416 | |
3811eed8 DSH |
417 | EVP_DecryptInit_ex() and EVP_DecryptUpdate() return 1 for success and 0 for failure. |
418 | EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success. | |
72b60351 | 419 | |
3811eed8 | 420 | EVP_CipherInit_ex() and EVP_CipherUpdate() return 1 for success and 0 for failure. |
21d5ed98 | 421 | EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success. |
72b60351 | 422 | |
f7397f0d RL |
423 | EVP_Cipher() returns the amount of encrypted / decrypted bytes, or -1 |
424 | on failure, if the flag B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is set for the | |
425 | cipher. EVP_Cipher() returns 1 on success or 0 on failure, if the flag | |
426 | B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is not set for the cipher. | |
427 | ||
05fdb8d3 | 428 | EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure. |
3f2b5a88 DSH |
429 | |
430 | EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() | |
431 | return an B<EVP_CIPHER> structure or NULL on error. | |
432 | ||
433 | EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return a NID. | |
434 | ||
435 | EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block | |
436 | size. | |
437 | ||
438 | EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key | |
439 | length. | |
440 | ||
f2e5ca84 DSH |
441 | EVP_CIPHER_CTX_set_padding() always returns 1. |
442 | ||
3f2b5a88 DSH |
443 | EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV |
444 | length or zero if the cipher does not use an IV. | |
445 | ||
dc64dc2e SL |
446 | EVP_CIPHER_CTX_tag_length() return the tag length or zero if the cipher does not |
447 | use a tag. | |
448 | ||
41e68ef2 DSH |
449 | EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the NID of the cipher's |
450 | OBJECT IDENTIFIER or NID_undef if it has no defined OBJECT IDENTIFIER. | |
451 | ||
452 | EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure. | |
453 | ||
c03726ca | 454 | EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater |
49c9c1b3 | 455 | than zero for success and zero or a negative number on failure. |
41e68ef2 | 456 | |
5c5eb286 PS |
457 | EVP_CIPHER_CTX_rand_key() returns 1 for success. |
458 | ||
a91dedca DSH |
459 | =head1 CIPHER LISTING |
460 | ||
461 | All algorithms have a fixed key length unless otherwise stated. | |
462 | ||
6e4618a0 | 463 | Refer to L</SEE ALSO> for the full list of ciphers available through the EVP |
8fa4d95e RT |
464 | interface. |
465 | ||
a91dedca DSH |
466 | =over 4 |
467 | ||
468 | =item EVP_enc_null() | |
469 | ||
470 | Null cipher: does nothing. | |
471 | ||
8fa4d95e | 472 | =back |
a91dedca | 473 | |
485d3361 | 474 | =head1 AEAD INTERFACE |
a91dedca | 475 | |
8fa4d95e RT |
476 | The EVP interface for Authenticated Encryption with Associated Data (AEAD) |
477 | modes are subtly altered and several additional I<ctrl> operations are supported | |
478 | depending on the mode specified. | |
a91dedca | 479 | |
8fa4d95e RT |
480 | To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(), |
481 | EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output | |
482 | parameter B<out> set to B<NULL>. | |
a91dedca | 483 | |
8fa4d95e RT |
484 | When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal() |
485 | indicates whether the operation was successful. If it does not indicate success, | |
486 | the authentication operation has failed and any output data B<MUST NOT> be used | |
487 | as it is corrupted. | |
a91dedca | 488 | |
8fa4d95e | 489 | =head2 GCM and OCB Modes |
a91dedca | 490 | |
8fa4d95e | 491 | The following I<ctrl>s are supported in GCM and OCB modes. |
a91dedca | 492 | |
8fa4d95e | 493 | =over 4 |
a91dedca | 494 | |
8fa4d95e | 495 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) |
a91dedca | 496 | |
8fa4d95e RT |
497 | Sets the IV length. This call can only be made before specifying an IV. If |
498 | not called a default IV length is used. | |
a91dedca | 499 | |
8fa4d95e RT |
500 | For GCM AES and OCB AES the default is 12 (i.e. 96 bits). For OCB mode the |
501 | maximum is 15. | |
a91dedca | 502 | |
8fa4d95e | 503 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag) |
a91dedca | 504 | |
8fa4d95e RT |
505 | Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>. |
506 | This call can only be made when encrypting data and B<after> all data has been | |
507 | processed (e.g. after an EVP_EncryptFinal() call). | |
a91dedca | 508 | |
8fa4d95e RT |
509 | For OCB, C<taglen> must either be 16 or the value previously set via |
510 | B<EVP_CTRL_AEAD_SET_TAG>. | |
a91dedca | 511 | |
8fa4d95e | 512 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag) |
a91dedca | 513 | |
8fa4d95e RT |
514 | Sets the expected tag to C<taglen> bytes from C<tag>. |
515 | The tag length can only be set before specifying an IV. | |
516 | C<taglen> must be between 1 and 16 inclusive. | |
a91dedca | 517 | |
8fa4d95e | 518 | For GCM, this call is only valid when decrypting data. |
a91dedca | 519 | |
8fa4d95e RT |
520 | For OCB, this call is valid when decrypting data to set the expected tag, |
521 | and before encryption to set the desired tag length. | |
a91dedca | 522 | |
8fa4d95e RT |
523 | In OCB mode, calling this before encryption with C<tag> set to C<NULL> sets the |
524 | tag length. If this is not called prior to encryption, a default tag length is | |
525 | used. | |
a91dedca | 526 | |
8fa4d95e RT |
527 | For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the |
528 | maximum tag length for OCB. | |
a91dedca | 529 | |
8fa4d95e | 530 | =back |
a91dedca | 531 | |
8fa4d95e | 532 | =head2 CCM Mode |
a91dedca | 533 | |
8fa4d95e RT |
534 | The EVP interface for CCM mode is similar to that of the GCM mode but with a |
535 | few additional requirements and different I<ctrl> values. | |
aa714f3a | 536 | |
8fa4d95e RT |
537 | For CCM mode, the total plaintext or ciphertext length B<MUST> be passed to |
538 | EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output | |
539 | and input parameters (B<in> and B<out>) set to B<NULL> and the length passed in | |
540 | the B<inl> parameter. | |
e4bbee96 | 541 | |
8fa4d95e | 542 | The following I<ctrl>s are supported in CCM mode. |
e4bbee96 | 543 | |
8fa4d95e | 544 | =over 4 |
aa714f3a | 545 | |
8fa4d95e | 546 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag) |
aa714f3a | 547 | |
8fa4d95e RT |
548 | This call is made to set the expected B<CCM> tag value when decrypting or |
549 | the length of the tag (with the C<tag> parameter set to NULL) when encrypting. | |
550 | The tag length is often referred to as B<M>. If not set a default value is | |
67c81ec3 TN |
551 | used (12 for AES). When decrypting, the tag needs to be set before passing |
552 | in data to be decrypted, but as in GCM and OCB mode, it can be set after | |
485d3361 | 553 | passing additional authenticated data (see L</AEAD INTERFACE>). |
aa714f3a | 554 | |
8fa4d95e | 555 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL) |
625b9d6b | 556 | |
8fa4d95e | 557 | Sets the CCM B<L> value. If not set a default is used (8 for AES). |
625b9d6b | 558 | |
8fa4d95e | 559 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) |
625b9d6b | 560 | |
8fa4d95e RT |
561 | Sets the CCM nonce (IV) length. This call can only be made before specifying an |
562 | nonce value. The nonce length is given by B<15 - L> so it is 7 by default for | |
563 | AES. | |
625b9d6b | 564 | |
a91dedca DSH |
565 | =back |
566 | ||
b1ceb439 TS |
567 | =head2 SIV Mode |
568 | ||
569 | For SIV mode ciphers the behaviour of the EVP interface is subtly | |
570 | altered and several additional ctrl operations are supported. | |
571 | ||
572 | To specify any additional authenticated data (AAD) and/or a Nonce, a call to | |
573 | EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made | |
574 | with the output parameter B<out> set to B<NULL>. | |
575 | ||
576 | RFC5297 states that the Nonce is the last piece of AAD before the actual | |
577 | encrypt/decrypt takes place. The API does not differentiate the Nonce from | |
578 | other AAD. | |
579 | ||
580 | When decrypting the return value of EVP_DecryptFinal() or EVP_CipherFinal() | |
581 | indicates if the operation was successful. If it does not indicate success | |
582 | the authentication operation has failed and any output data B<MUST NOT> | |
583 | be used as it is corrupted. | |
584 | ||
585 | The following ctrls are supported in both SIV modes. | |
586 | ||
587 | =over 4 | |
588 | ||
589 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag); | |
590 | ||
591 | Writes B<taglen> bytes of the tag value to the buffer indicated by B<tag>. | |
592 | This call can only be made when encrypting data and B<after> all data has been | |
593 | processed (e.g. after an EVP_EncryptFinal() call). For SIV mode the taglen must | |
594 | be 16. | |
595 | ||
596 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag); | |
597 | ||
598 | Sets the expected tag to B<taglen> bytes from B<tag>. This call is only legal | |
599 | when decrypting data and must be made B<before> any data is processed (e.g. | |
600 | before any EVP_DecryptUpdate() call). For SIV mode the taglen must be 16. | |
601 | ||
602 | =back | |
603 | ||
604 | SIV mode makes two passes over the input data, thus, only one call to | |
605 | EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made | |
606 | with B<out> set to a non-B<NULL> value. A call to EVP_Decrypt_Final() or | |
607 | EVP_CipherFinal() is not required, but will indicate if the update | |
608 | operation succeeded. | |
609 | ||
8fa4d95e | 610 | =head2 ChaCha20-Poly1305 |
aa714f3a | 611 | |
8fa4d95e | 612 | The following I<ctrl>s are supported for the ChaCha20-Poly1305 AEAD algorithm. |
aa714f3a | 613 | |
8fa4d95e | 614 | =over 4 |
aa714f3a | 615 | |
8fa4d95e | 616 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) |
aa714f3a | 617 | |
8fa4d95e RT |
618 | Sets the nonce length. This call can only be made before specifying the nonce. |
619 | If not called a default nonce length of 12 (i.e. 96 bits) is used. The maximum | |
27d56312 MC |
620 | nonce length is 12 bytes (i.e. 96-bits). If a nonce of less than 12 bytes is set |
621 | then the nonce is automatically padded with leading 0 bytes to make it 12 bytes | |
622 | in length. | |
c7497f34 | 623 | |
8fa4d95e | 624 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag) |
aa714f3a | 625 | |
8fa4d95e | 626 | Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>. |
aa714f3a | 627 | This call can only be made when encrypting data and B<after> all data has been |
8fa4d95e | 628 | processed (e.g. after an EVP_EncryptFinal() call). |
c7497f34 | 629 | |
8fa4d95e RT |
630 | C<taglen> specified here must be 16 (B<POLY1305_BLOCK_SIZE>, i.e. 128-bits) or |
631 | less. | |
aa714f3a | 632 | |
8fa4d95e | 633 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag) |
aa714f3a | 634 | |
8fa4d95e RT |
635 | Sets the expected tag to C<taglen> bytes from C<tag>. |
636 | The tag length can only be set before specifying an IV. | |
637 | C<taglen> must be between 1 and 16 (B<POLY1305_BLOCK_SIZE>) inclusive. | |
638 | This call is only valid when decrypting data. | |
aa714f3a | 639 | |
8fa4d95e | 640 | =back |
aa714f3a | 641 | |
72b60351 DSH |
642 | =head1 NOTES |
643 | ||
644 | Where possible the B<EVP> interface to symmetric ciphers should be used in | |
645 | preference to the low level interfaces. This is because the code then becomes | |
75b76068 JW |
646 | transparent to the cipher used and much more flexible. Additionally, the |
647 | B<EVP> interface will ensure the use of platform specific cryptographic | |
648 | acceleration such as AES-NI (the low level interfaces do not provide the | |
649 | guarantee). | |
72b60351 | 650 | |
c7497f34 | 651 | PKCS padding works by adding B<n> padding bytes of value B<n> to make the total |
72b60351 DSH |
652 | length of the encrypted data a multiple of the block size. Padding is always |
653 | added so if the data is already a multiple of the block size B<n> will equal | |
654 | the block size. For example if the block size is 8 and 11 bytes are to be | |
655 | encrypted then 5 padding bytes of value 5 will be added. | |
656 | ||
657 | When decrypting the final block is checked to see if it has the correct form. | |
658 | ||
f2e5ca84 DSH |
659 | Although the decryption operation can produce an error if padding is enabled, |
660 | it is not a strong test that the input data or key is correct. A random block | |
661 | has better than 1 in 256 chance of being of the correct format and problems with | |
662 | the input data earlier on will not produce a final decrypt error. | |
663 | ||
664 | If padding is disabled then the decryption operation will always succeed if | |
665 | the total amount of data decrypted is a multiple of the block size. | |
72b60351 | 666 | |
3811eed8 DSH |
667 | The functions EVP_EncryptInit(), EVP_EncryptFinal(), EVP_DecryptInit(), |
668 | EVP_CipherInit() and EVP_CipherFinal() are obsolete but are retained for | |
669 | compatibility with existing code. New code should use EVP_EncryptInit_ex(), | |
670 | EVP_EncryptFinal_ex(), EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(), | |
671 | EVP_CipherInit_ex() and EVP_CipherFinal_ex() because they can reuse an | |
672 | existing context without allocating and freeing it up on each call. | |
a91dedca | 673 | |
32745fcc DB |
674 | There are some differences between functions EVP_CipherInit() and |
675 | EVP_CipherInit_ex(), significant in some circumstances. EVP_CipherInit() fills | |
676 | the passed context object with zeros. As a consequence, EVP_CipherInit() does | |
677 | not allow step-by-step initialization of the ctx when the I<key> and I<iv> are | |
678 | passed in separate calls. It also means that the flags set for the CTX are | |
679 | removed, and it is especially important for the | |
680 | B<EVP_CIPHER_CTX_FLAG_WRAP_ALLOW> flag treated specially in | |
681 | EVP_CipherInit_ex(). | |
682 | ||
91da5e77 RS |
683 | EVP_get_cipherbynid(), and EVP_get_cipherbyobj() are implemented as macros. |
684 | ||
72b60351 DSH |
685 | =head1 BUGS |
686 | ||
8fa4d95e RT |
687 | B<EVP_MAX_KEY_LENGTH> and B<EVP_MAX_IV_LENGTH> only refer to the internal |
688 | ciphers with default key lengths. If custom ciphers exceed these values the | |
689 | results are unpredictable. This is because it has become standard practice to | |
690 | define a generic key as a fixed unsigned char array containing | |
691 | B<EVP_MAX_KEY_LENGTH> bytes. | |
a91dedca | 692 | |
c8973693 | 693 | The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested |
a91dedca DSH |
694 | for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode. |
695 | ||
696 | =head1 EXAMPLES | |
697 | ||
fd4592be | 698 | Encrypt a string using IDEA: |
18135561 DSH |
699 | |
700 | int do_crypt(char *outfile) | |
2947af32 BB |
701 | { |
702 | unsigned char outbuf[1024]; | |
703 | int outlen, tmplen; | |
704 | /* | |
705 | * Bogus key and IV: we'd normally set these from | |
706 | * another source. | |
707 | */ | |
708 | unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; | |
709 | unsigned char iv[] = {1,2,3,4,5,6,7,8}; | |
710 | char intext[] = "Some Crypto Text"; | |
711 | EVP_CIPHER_CTX *ctx; | |
712 | FILE *out; | |
713 | ||
714 | ctx = EVP_CIPHER_CTX_new(); | |
715 | EVP_EncryptInit_ex(ctx, EVP_idea_cbc(), NULL, key, iv); | |
716 | ||
717 | if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) { | |
718 | /* Error */ | |
519a5d1e | 719 | EVP_CIPHER_CTX_free(ctx); |
2947af32 BB |
720 | return 0; |
721 | } | |
722 | /* | |
723 | * Buffer passed to EVP_EncryptFinal() must be after data just | |
724 | * encrypted to avoid overwriting it. | |
725 | */ | |
726 | if (!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) { | |
727 | /* Error */ | |
519a5d1e | 728 | EVP_CIPHER_CTX_free(ctx); |
2947af32 BB |
729 | return 0; |
730 | } | |
731 | outlen += tmplen; | |
732 | EVP_CIPHER_CTX_free(ctx); | |
733 | /* | |
734 | * Need binary mode for fopen because encrypted data is | |
735 | * binary data. Also cannot use strlen() on it because | |
736 | * it won't be NUL terminated and may contain embedded | |
737 | * NULs. | |
738 | */ | |
739 | out = fopen(outfile, "wb"); | |
519a5d1e GZ |
740 | if (out == NULL) { |
741 | /* Error */ | |
742 | return 0; | |
743 | } | |
2947af32 BB |
744 | fwrite(outbuf, 1, outlen, out); |
745 | fclose(out); | |
746 | return 1; | |
747 | } | |
18135561 DSH |
748 | |
749 | The ciphertext from the above example can be decrypted using the B<openssl> | |
fd4592be | 750 | utility with the command line (shown on two lines for clarity): |
c7497f34 | 751 | |
2947af32 BB |
752 | openssl idea -d \ |
753 | -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 <filename | |
18135561 | 754 | |
fd4592be JS |
755 | General encryption and decryption function example using FILE I/O and AES128 |
756 | with a 128-bit key: | |
18135561 DSH |
757 | |
758 | int do_crypt(FILE *in, FILE *out, int do_encrypt) | |
2947af32 BB |
759 | { |
760 | /* Allow enough space in output buffer for additional block */ | |
761 | unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH]; | |
762 | int inlen, outlen; | |
763 | EVP_CIPHER_CTX *ctx; | |
764 | /* | |
765 | * Bogus key and IV: we'd normally set these from | |
766 | * another source. | |
767 | */ | |
768 | unsigned char key[] = "0123456789abcdeF"; | |
769 | unsigned char iv[] = "1234567887654321"; | |
770 | ||
771 | /* Don't set key or IV right away; we want to check lengths */ | |
772 | ctx = EVP_CIPHER_CTX_new(); | |
773 | EVP_CipherInit_ex(&ctx, EVP_aes_128_cbc(), NULL, NULL, NULL, | |
774 | do_encrypt); | |
775 | OPENSSL_assert(EVP_CIPHER_CTX_key_length(ctx) == 16); | |
776 | OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) == 16); | |
777 | ||
778 | /* Now we can set key and IV */ | |
779 | EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, do_encrypt); | |
780 | ||
781 | for (;;) { | |
782 | inlen = fread(inbuf, 1, 1024, in); | |
783 | if (inlen <= 0) | |
784 | break; | |
785 | if (!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) { | |
786 | /* Error */ | |
787 | EVP_CIPHER_CTX_free(ctx); | |
788 | return 0; | |
789 | } | |
790 | fwrite(outbuf, 1, outlen, out); | |
791 | } | |
792 | if (!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) { | |
793 | /* Error */ | |
794 | EVP_CIPHER_CTX_free(ctx); | |
795 | return 0; | |
796 | } | |
797 | fwrite(outbuf, 1, outlen, out); | |
798 | ||
799 | EVP_CIPHER_CTX_free(ctx); | |
800 | return 1; | |
801 | } | |
18135561 DSH |
802 | |
803 | ||
72b60351 DSH |
804 | =head1 SEE ALSO |
805 | ||
b97fdb57 | 806 | L<evp(7)> |
72b60351 | 807 | |
8fa4d95e RT |
808 | Supported ciphers are listed in: |
809 | ||
d7cea0b8 RS |
810 | L<EVP_aes_128_gcm(3)>, |
811 | L<EVP_aria_128_gcm(3)>, | |
812 | L<EVP_bf_cbc(3)>, | |
813 | L<EVP_camellia_128_ecb(3)>, | |
814 | L<EVP_cast5_cbc(3)>, | |
8fa4d95e | 815 | L<EVP_chacha20(3)>, |
d7cea0b8 RS |
816 | L<EVP_des_cbc(3)>, |
817 | L<EVP_desx_cbc(3)>, | |
818 | L<EVP_idea_cbc(3)>, | |
819 | L<EVP_rc2_cbc(3)>, | |
8fa4d95e | 820 | L<EVP_rc4(3)>, |
d7cea0b8 RS |
821 | L<EVP_rc5_32_12_16_cbc(3)>, |
822 | L<EVP_seed_cbc(3)>, | |
823 | L<EVP_sm4_cbc(3)> | |
8fa4d95e | 824 | |
72b60351 DSH |
825 | =head1 HISTORY |
826 | ||
fc5ecadd | 827 | Support for OCB mode was added in OpenSSL 1.1.0. |
a528d4f0 | 828 | |
05fdb8d3 RL |
829 | B<EVP_CIPHER_CTX> was made opaque in OpenSSL 1.1.0. As a result, |
830 | EVP_CIPHER_CTX_reset() appeared and EVP_CIPHER_CTX_cleanup() | |
831 | disappeared. EVP_CIPHER_CTX_init() remains as an alias for | |
832 | EVP_CIPHER_CTX_reset(). | |
833 | ||
550f974a RL |
834 | The EVP_CIPHER_fetch(), EVP_CIPHER_free(), EVP_CIPHER_up_ref(), |
835 | EVP_CIPHER_CTX_set_params() and EVP_CIPHER_CTX_get_params() functions | |
836 | were added in 3.0. | |
837 | ||
e2f92610 RS |
838 | =head1 COPYRIGHT |
839 | ||
0d664759 | 840 | Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 | 841 | |
4746f25a | 842 | Licensed under the Apache License 2.0 (the "License"). You may not use |
e2f92610 RS |
843 | this file except in compliance with the License. You can obtain a copy |
844 | in the file LICENSE in the source distribution or at | |
845 | L<https://www.openssl.org/source/license.html>. | |
846 | ||
847 | =cut |