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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, |
8fa4d95e RT |
6 | EVP_CIPHER_CTX_new, |
7 | EVP_CIPHER_CTX_reset, | |
8 | EVP_CIPHER_CTX_free, | |
9 | EVP_EncryptInit_ex, | |
10 | EVP_EncryptUpdate, | |
11 | EVP_EncryptFinal_ex, | |
12 | EVP_DecryptInit_ex, | |
13 | EVP_DecryptUpdate, | |
14 | EVP_DecryptFinal_ex, | |
15 | EVP_CipherInit_ex, | |
16 | EVP_CipherUpdate, | |
17 | EVP_CipherFinal_ex, | |
18 | EVP_CIPHER_CTX_set_key_length, | |
19 | EVP_CIPHER_CTX_ctrl, | |
20 | EVP_EncryptInit, | |
21 | EVP_EncryptFinal, | |
22 | EVP_DecryptInit, | |
23 | EVP_DecryptFinal, | |
24 | EVP_CipherInit, | |
25 | EVP_CipherFinal, | |
26 | EVP_get_cipherbyname, | |
27 | EVP_get_cipherbynid, | |
28 | EVP_get_cipherbyobj, | |
c750bc08 | 29 | EVP_CIPHER_name, |
1d2622d4 | 30 | EVP_CIPHER_provider, |
8fa4d95e RT |
31 | EVP_CIPHER_nid, |
32 | EVP_CIPHER_block_size, | |
33 | EVP_CIPHER_key_length, | |
34 | EVP_CIPHER_iv_length, | |
35 | EVP_CIPHER_flags, | |
36 | EVP_CIPHER_mode, | |
37 | EVP_CIPHER_type, | |
38 | EVP_CIPHER_CTX_cipher, | |
c750bc08 | 39 | EVP_CIPHER_CTX_name, |
8fa4d95e RT |
40 | EVP_CIPHER_CTX_nid, |
41 | EVP_CIPHER_CTX_block_size, | |
42 | EVP_CIPHER_CTX_key_length, | |
43 | EVP_CIPHER_CTX_iv_length, | |
44 | EVP_CIPHER_CTX_get_app_data, | |
45 | EVP_CIPHER_CTX_set_app_data, | |
46 | EVP_CIPHER_CTX_type, | |
47 | EVP_CIPHER_CTX_flags, | |
48 | EVP_CIPHER_CTX_mode, | |
49 | EVP_CIPHER_param_to_asn1, | |
50 | EVP_CIPHER_asn1_to_param, | |
51 | EVP_CIPHER_CTX_set_padding, | |
c540f00f RL |
52 | EVP_enc_null, |
53 | EVP_CIPHER_do_all_ex | |
8fa4d95e | 54 | - EVP cipher routines |
72b60351 DSH |
55 | |
56 | =head1 SYNOPSIS | |
57 | ||
b97fdb57 RL |
58 | =for comment generic |
59 | ||
72b60351 DSH |
60 | #include <openssl/evp.h> |
61 | ||
2cafb1df RL |
62 | EVP_CIPHER *EVP_CIPHER_fetch(OPENSSL_CTX *ctx, const char *algorithm, |
63 | const char *properties); | |
05fdb8d3 RL |
64 | EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void); |
65 | int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx); | |
66 | void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx); | |
3811eed8 DSH |
67 | |
68 | int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 69 | ENGINE *impl, const unsigned char *key, const unsigned char *iv); |
a91dedca | 70 | int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
7bbb0050 | 71 | int *outl, const unsigned char *in, int inl); |
e9b77246 | 72 | int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl); |
3811eed8 DSH |
73 | |
74 | int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 75 | ENGINE *impl, const unsigned char *key, const unsigned char *iv); |
3811eed8 | 76 | int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
7bbb0050 | 77 | int *outl, const unsigned char *in, int inl); |
e9b77246 | 78 | int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
3811eed8 DSH |
79 | |
80 | int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 81 | ENGINE *impl, const unsigned char *key, const unsigned char *iv, int enc); |
3811eed8 | 82 | int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
b38fa985 | 83 | int *outl, const unsigned char *in, int inl); |
e9b77246 | 84 | int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
3811eed8 DSH |
85 | |
86 | int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
b38fa985 | 87 | const unsigned char *key, const unsigned char *iv); |
e9b77246 | 88 | int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl); |
4d524e10 | 89 | |
a91dedca | 90 | int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, |
b38fa985 | 91 | const unsigned char *key, const unsigned char *iv); |
e9b77246 | 92 | int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
4d524e10 | 93 | |
a91dedca | 94 | int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, |
b38fa985 | 95 | const unsigned char *key, const unsigned char *iv, int enc); |
e9b77246 | 96 | int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl); |
72b60351 | 97 | |
f2e5ca84 | 98 | int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding); |
a91dedca DSH |
99 | int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen); |
100 | int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr); | |
5c5eb286 | 101 | int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key); |
72b60351 DSH |
102 | |
103 | const EVP_CIPHER *EVP_get_cipherbyname(const char *name); | |
91da5e77 RS |
104 | const EVP_CIPHER *EVP_get_cipherbynid(int nid); |
105 | const EVP_CIPHER *EVP_get_cipherbyobj(const ASN1_OBJECT *a); | |
106 | ||
107 | int EVP_CIPHER_nid(const EVP_CIPHER *e); | |
c750bc08 | 108 | const char *EVP_CIPHER_name(const EVP_CIPHER *cipher); |
1d2622d4 | 109 | const OSSL_PROVIDER *EVP_CIPHER_provider(const EVP_CIPHER *cipher); |
91da5e77 | 110 | int EVP_CIPHER_block_size(const EVP_CIPHER *e); |
91da5e77 RS |
111 | int EVP_CIPHER_key_length(const EVP_CIPHER *e); |
112 | int EVP_CIPHER_iv_length(const EVP_CIPHER *e); | |
113 | unsigned long EVP_CIPHER_flags(const EVP_CIPHER *e); | |
114 | unsigned long EVP_CIPHER_mode(const EVP_CIPHER *e); | |
72b60351 | 115 | int EVP_CIPHER_type(const EVP_CIPHER *ctx); |
a91dedca | 116 | |
05fdb8d3 RL |
117 | const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *ctx); |
118 | int EVP_CIPHER_CTX_nid(const EVP_CIPHER_CTX *ctx); | |
c750bc08 | 119 | const char *EVP_CIPHER_CTX_name(const EVP_CIPHER_CTX *ctx); |
05fdb8d3 RL |
120 | int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *ctx); |
121 | int EVP_CIPHER_CTX_key_length(const EVP_CIPHER_CTX *ctx); | |
122 | int EVP_CIPHER_CTX_iv_length(const EVP_CIPHER_CTX *ctx); | |
123 | void *EVP_CIPHER_CTX_get_app_data(const EVP_CIPHER_CTX *ctx); | |
124 | void EVP_CIPHER_CTX_set_app_data(const EVP_CIPHER_CTX *ctx, void *data); | |
125 | int EVP_CIPHER_CTX_type(const EVP_CIPHER_CTX *ctx); | |
05fdb8d3 | 126 | int EVP_CIPHER_CTX_mode(const EVP_CIPHER_CTX *ctx); |
72b60351 | 127 | |
3f2b5a88 DSH |
128 | int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type); |
129 | int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type); | |
130 | ||
c540f00f RL |
131 | void EVP_CIPHER_do_all_ex(OPENSSL_CTX *libctx, |
132 | void (*fn)(EVP_CIPHER *cipher, void *arg), | |
133 | void *arg); | |
134 | ||
72b60351 DSH |
135 | =head1 DESCRIPTION |
136 | ||
137 | The EVP cipher routines are a high level interface to certain | |
138 | symmetric ciphers. | |
139 | ||
2cafb1df RL |
140 | EVP_CIPHER_fetch() fetches the cipher implementation for the given |
141 | B<algorithm> from any provider offering it, within the criteria given | |
142 | by the B<properties>. | |
143 | See L<provider(7)/Fetching algorithms> for further information. | |
144 | ||
145 | The returned value must eventually be freed with | |
146 | L<EVP_CIPHER_meth_free(3)>. | |
147 | ||
05fdb8d3 RL |
148 | EVP_CIPHER_CTX_new() creates a cipher context. |
149 | ||
150 | EVP_CIPHER_CTX_free() clears all information from a cipher context | |
151 | and free up any allocated memory associate with it, including B<ctx> | |
152 | itself. This function should be called after all operations using a | |
153 | cipher are complete so sensitive information does not remain in | |
154 | memory. | |
3811eed8 DSH |
155 | |
156 | EVP_EncryptInit_ex() sets up cipher context B<ctx> for encryption | |
2cafb1df RL |
157 | with cipher B<type>. B<type> is typically supplied by a function such |
158 | as EVP_aes_256_cbc(), or a value explicitly fetched with | |
159 | EVP_CIPHER_fetch(). If B<impl> is non-NULL, its implementation of the | |
160 | cipher B<type> is used if there is one, and if not, the default | |
161 | implementation is used. B<key> is the symmetric key to use | |
3811eed8 DSH |
162 | and B<iv> is the IV to use (if necessary), the actual number of bytes |
163 | used for the key and IV depends on the cipher. It is possible to set | |
164 | all parameters to NULL except B<type> in an initial call and supply | |
165 | the remaining parameters in subsequent calls, all of which have B<type> | |
166 | set to NULL. This is done when the default cipher parameters are not | |
167 | appropriate. | |
72b60351 DSH |
168 | |
169 | EVP_EncryptUpdate() encrypts B<inl> bytes from the buffer B<in> and | |
170 | writes the encrypted version to B<out>. This function can be called | |
171 | multiple times to encrypt successive blocks of data. The amount | |
172 | of data written depends on the block alignment of the encrypted data: | |
173 | as a result the amount of data written may be anything from zero bytes | |
5211e094 | 174 | to (inl + cipher_block_size - 1) so B<out> should contain sufficient |
c3a73daf AP |
175 | room. The actual number of bytes written is placed in B<outl>. It also |
176 | checks if B<in> and B<out> are partially overlapping, and if they are | |
177 | 0 is returned to indicate failure. | |
72b60351 | 178 | |
3811eed8 | 179 | If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts |
f2e5ca84 | 180 | the "final" data, that is any data that remains in a partial block. |
a09474dd RS |
181 | It uses standard block padding (aka PKCS padding) as described in |
182 | the NOTES section, below. The encrypted | |
f2e5ca84 DSH |
183 | final data is written to B<out> which should have sufficient space for |
184 | one cipher block. The number of bytes written is placed in B<outl>. After | |
185 | this function is called the encryption operation is finished and no further | |
186 | calls to EVP_EncryptUpdate() should be made. | |
187 | ||
3811eed8 | 188 | If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more |
f2e5ca84 | 189 | data and it will return an error if any data remains in a partial block: |
c7497f34 | 190 | that is if the total data length is not a multiple of the block size. |
72b60351 | 191 | |
3811eed8 | 192 | EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex() are the |
72b60351 | 193 | corresponding decryption operations. EVP_DecryptFinal() will return an |
f2e5ca84 DSH |
194 | error code if padding is enabled and the final block is not correctly |
195 | formatted. The parameters and restrictions are identical to the encryption | |
196 | operations except that if padding is enabled the decrypted data buffer B<out> | |
197 | passed to EVP_DecryptUpdate() should have sufficient room for | |
198 | (B<inl> + cipher_block_size) bytes unless the cipher block size is 1 in | |
199 | which case B<inl> bytes is sufficient. | |
72b60351 | 200 | |
3811eed8 DSH |
201 | EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex() are |
202 | functions that can be used for decryption or encryption. The operation | |
203 | performed depends on the value of the B<enc> parameter. It should be set | |
204 | to 1 for encryption, 0 for decryption and -1 to leave the value unchanged | |
205 | (the actual value of 'enc' being supplied in a previous call). | |
206 | ||
05fdb8d3 RL |
207 | EVP_CIPHER_CTX_reset() clears all information from a cipher context |
208 | and free up any allocated memory associate with it, except the B<ctx> | |
209 | itself. This function should be called anytime B<ctx> is to be reused | |
210 | for another EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal() | |
211 | series of calls. | |
3811eed8 DSH |
212 | |
213 | EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit() behave in a | |
d4a43700 | 214 | similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and |
b45497c3 | 215 | EVP_CipherInit_ex() except they always use the default cipher implementation. |
72b60351 | 216 | |
538860a3 RS |
217 | EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() are |
218 | identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and | |
219 | EVP_CipherFinal_ex(). In previous releases they also cleaned up | |
220 | the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean() | |
221 | must be called to free any context resources. | |
72b60351 | 222 | |
3f2b5a88 DSH |
223 | EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() |
224 | return an EVP_CIPHER structure when passed a cipher name, a NID or an | |
225 | ASN1_OBJECT structure. | |
226 | ||
227 | EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return the NID of a cipher when | |
228 | passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> structure. The actual NID | |
229 | value is an internal value which may not have a corresponding OBJECT | |
230 | IDENTIFIER. | |
231 | ||
83f68df3 CPLG |
232 | EVP_CIPHER_CTX_set_padding() enables or disables padding. This |
233 | function should be called after the context is set up for encryption | |
234 | or decryption with EVP_EncryptInit_ex(), EVP_DecryptInit_ex() or | |
235 | EVP_CipherInit_ex(). By default encryption operations are padded using | |
236 | standard block padding and the padding is checked and removed when | |
237 | decrypting. If the B<pad> parameter is zero then no padding is | |
238 | performed, the total amount of data encrypted or decrypted must then | |
239 | be a multiple of the block size or an error will occur. | |
f2e5ca84 | 240 | |
3f2b5a88 DSH |
241 | EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key |
242 | length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> | |
243 | structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum key length | |
a91dedca DSH |
244 | for all ciphers. Note: although EVP_CIPHER_key_length() is fixed for a |
245 | given cipher, the value of EVP_CIPHER_CTX_key_length() may be different | |
246 | for variable key length ciphers. | |
247 | ||
248 | EVP_CIPHER_CTX_set_key_length() sets the key length of the cipher ctx. | |
249 | If the cipher is a fixed length cipher then attempting to set the key | |
250 | length to any value other than the fixed value is an error. | |
3f2b5a88 DSH |
251 | |
252 | EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV | |
253 | length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>. | |
254 | It will return zero if the cipher does not use an IV. The constant | |
255 | B<EVP_MAX_IV_LENGTH> is the maximum IV length for all ciphers. | |
256 | ||
257 | EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block | |
258 | size of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> | |
14f46560 | 259 | structure. The constant B<EVP_MAX_BLOCK_LENGTH> is also the maximum block |
3f2b5a88 DSH |
260 | length for all ciphers. |
261 | ||
262 | EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the type of the passed | |
263 | cipher or context. This "type" is the actual NID of the cipher OBJECT | |
264 | IDENTIFIER as such it ignores the cipher parameters and 40 bit RC2 and | |
41e68ef2 DSH |
265 | 128 bit RC2 have the same NID. If the cipher does not have an object |
266 | identifier or does not have ASN1 support this function will return | |
267 | B<NID_undef>. | |
3f2b5a88 | 268 | |
c750bc08 RL |
269 | EVP_CIPHER_name() and EVP_CIPHER_CTX_name() return the name of the passed |
270 | cipher or context. | |
271 | ||
1d2622d4 RL |
272 | EVP_CIPHER_provider() returns an B<OSSL_PROVIDER> pointer to the provider |
273 | that implements the given B<EVP_CIPHER>. | |
274 | ||
3f2b5a88 DSH |
275 | EVP_CIPHER_CTX_cipher() returns the B<EVP_CIPHER> structure when passed |
276 | an B<EVP_CIPHER_CTX> structure. | |
277 | ||
a91dedca | 278 | EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return the block cipher mode: |
338ead0f PS |
279 | EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE, |
280 | EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE, | |
11dbdc07 MC |
281 | EVP_CIPH_WRAP_MODE, EVP_CIPH_OCB_MODE or EVP_CIPH_SIV_MODE. If the cipher is a |
282 | stream cipher then EVP_CIPH_STREAM_CIPHER is returned. | |
283 | ||
284 | EVP_CIPHER_flags() returns any flags associated with the cipher. See | |
285 | EVP_CIPHER_meth_set_flags() for a list of currently defined flags. | |
a91dedca | 286 | |
3f2b5a88 DSH |
287 | EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter" based |
288 | on the passed cipher. This will typically include any parameters and an | |
289 | IV. The cipher IV (if any) must be set when this call is made. This call | |
290 | should be made before the cipher is actually "used" (before any | |
291 | EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example). This function | |
292 | may fail if the cipher does not have any ASN1 support. | |
293 | ||
294 | EVP_CIPHER_asn1_to_param() sets the cipher parameters based on an ASN1 | |
295 | AlgorithmIdentifier "parameter". The precise effect depends on the cipher | |
296 | In the case of RC2, for example, it will set the IV and effective key length. | |
297 | This function should be called after the base cipher type is set but before | |
298 | the key is set. For example EVP_CipherInit() will be called with the IV and | |
299 | key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally | |
300 | EVP_CipherInit() again with all parameters except the key set to NULL. It is | |
301 | possible for this function to fail if the cipher does not have any ASN1 support | |
302 | or the parameters cannot be set (for example the RC2 effective key length | |
a91dedca DSH |
303 | is not supported. |
304 | ||
305 | EVP_CIPHER_CTX_ctrl() allows various cipher specific parameters to be determined | |
aa714f3a | 306 | and set. |
3f2b5a88 | 307 | |
5c5eb286 PS |
308 | EVP_CIPHER_CTX_rand_key() generates a random key of the appropriate length |
309 | based on the cipher context. The EVP_CIPHER can provide its own random key | |
310 | generation routine to support keys of a specific form. B<Key> must point to a | |
311 | buffer at least as big as the value returned by EVP_CIPHER_CTX_key_length(). | |
312 | ||
c540f00f RL |
313 | EVP_CIPHER_do_all_ex() traverses all ciphers implemented by all activated |
314 | providers in the given library context I<libctx>, and for each of the | |
315 | implementations, calls the given function I<fn> with the implementation method | |
316 | and the given I<arg> as argument. | |
317 | ||
72b60351 DSH |
318 | =head1 RETURN VALUES |
319 | ||
2cafb1df RL |
320 | EVP_CIPHER_fetch() returns a pointer to a B<EVP_CIPHER> for success |
321 | and B<NULL> for failure. | |
322 | ||
05fdb8d3 RL |
323 | EVP_CIPHER_CTX_new() returns a pointer to a newly created |
324 | B<EVP_CIPHER_CTX> for success and B<NULL> for failure. | |
325 | ||
0e304b7f NL |
326 | EVP_EncryptInit_ex(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex() |
327 | return 1 for success and 0 for failure. | |
72b60351 | 328 | |
3811eed8 DSH |
329 | EVP_DecryptInit_ex() and EVP_DecryptUpdate() return 1 for success and 0 for failure. |
330 | EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success. | |
72b60351 | 331 | |
3811eed8 | 332 | EVP_CipherInit_ex() and EVP_CipherUpdate() return 1 for success and 0 for failure. |
21d5ed98 | 333 | EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success. |
72b60351 | 334 | |
05fdb8d3 | 335 | EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure. |
3f2b5a88 DSH |
336 | |
337 | EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() | |
338 | return an B<EVP_CIPHER> structure or NULL on error. | |
339 | ||
340 | EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return a NID. | |
341 | ||
342 | EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block | |
343 | size. | |
344 | ||
345 | EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key | |
346 | length. | |
347 | ||
f2e5ca84 DSH |
348 | EVP_CIPHER_CTX_set_padding() always returns 1. |
349 | ||
3f2b5a88 DSH |
350 | EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV |
351 | length or zero if the cipher does not use an IV. | |
352 | ||
41e68ef2 DSH |
353 | EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the NID of the cipher's |
354 | OBJECT IDENTIFIER or NID_undef if it has no defined OBJECT IDENTIFIER. | |
355 | ||
356 | EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure. | |
357 | ||
c03726ca | 358 | EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater |
49c9c1b3 | 359 | than zero for success and zero or a negative number on failure. |
41e68ef2 | 360 | |
5c5eb286 PS |
361 | EVP_CIPHER_CTX_rand_key() returns 1 for success. |
362 | ||
a91dedca DSH |
363 | =head1 CIPHER LISTING |
364 | ||
365 | All algorithms have a fixed key length unless otherwise stated. | |
366 | ||
8fa4d95e RT |
367 | Refer to L<SEE ALSO> for the full list of ciphers available through the EVP |
368 | interface. | |
369 | ||
a91dedca DSH |
370 | =over 4 |
371 | ||
372 | =item EVP_enc_null() | |
373 | ||
374 | Null cipher: does nothing. | |
375 | ||
8fa4d95e | 376 | =back |
a91dedca | 377 | |
8fa4d95e | 378 | =head1 AEAD Interface |
a91dedca | 379 | |
8fa4d95e RT |
380 | The EVP interface for Authenticated Encryption with Associated Data (AEAD) |
381 | modes are subtly altered and several additional I<ctrl> operations are supported | |
382 | depending on the mode specified. | |
a91dedca | 383 | |
8fa4d95e RT |
384 | To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(), |
385 | EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output | |
386 | parameter B<out> set to B<NULL>. | |
a91dedca | 387 | |
8fa4d95e RT |
388 | When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal() |
389 | indicates whether the operation was successful. If it does not indicate success, | |
390 | the authentication operation has failed and any output data B<MUST NOT> be used | |
391 | as it is corrupted. | |
a91dedca | 392 | |
8fa4d95e | 393 | =head2 GCM and OCB Modes |
a91dedca | 394 | |
8fa4d95e | 395 | The following I<ctrl>s are supported in GCM and OCB modes. |
a91dedca | 396 | |
8fa4d95e | 397 | =over 4 |
a91dedca | 398 | |
8fa4d95e | 399 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) |
a91dedca | 400 | |
8fa4d95e RT |
401 | Sets the IV length. This call can only be made before specifying an IV. If |
402 | not called a default IV length is used. | |
a91dedca | 403 | |
8fa4d95e RT |
404 | For GCM AES and OCB AES the default is 12 (i.e. 96 bits). For OCB mode the |
405 | maximum is 15. | |
a91dedca | 406 | |
8fa4d95e | 407 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag) |
a91dedca | 408 | |
8fa4d95e RT |
409 | Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>. |
410 | This call can only be made when encrypting data and B<after> all data has been | |
411 | processed (e.g. after an EVP_EncryptFinal() call). | |
a91dedca | 412 | |
8fa4d95e RT |
413 | For OCB, C<taglen> must either be 16 or the value previously set via |
414 | B<EVP_CTRL_AEAD_SET_TAG>. | |
a91dedca | 415 | |
8fa4d95e | 416 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag) |
a91dedca | 417 | |
8fa4d95e RT |
418 | Sets the expected tag to C<taglen> bytes from C<tag>. |
419 | The tag length can only be set before specifying an IV. | |
420 | C<taglen> must be between 1 and 16 inclusive. | |
a91dedca | 421 | |
8fa4d95e | 422 | For GCM, this call is only valid when decrypting data. |
a91dedca | 423 | |
8fa4d95e RT |
424 | For OCB, this call is valid when decrypting data to set the expected tag, |
425 | and before encryption to set the desired tag length. | |
a91dedca | 426 | |
8fa4d95e RT |
427 | In OCB mode, calling this before encryption with C<tag> set to C<NULL> sets the |
428 | tag length. If this is not called prior to encryption, a default tag length is | |
429 | used. | |
a91dedca | 430 | |
8fa4d95e RT |
431 | For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the |
432 | maximum tag length for OCB. | |
a91dedca | 433 | |
8fa4d95e | 434 | =back |
a91dedca | 435 | |
8fa4d95e | 436 | =head2 CCM Mode |
a91dedca | 437 | |
8fa4d95e RT |
438 | The EVP interface for CCM mode is similar to that of the GCM mode but with a |
439 | few additional requirements and different I<ctrl> values. | |
aa714f3a | 440 | |
8fa4d95e RT |
441 | For CCM mode, the total plaintext or ciphertext length B<MUST> be passed to |
442 | EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output | |
443 | and input parameters (B<in> and B<out>) set to B<NULL> and the length passed in | |
444 | the B<inl> parameter. | |
e4bbee96 | 445 | |
8fa4d95e | 446 | The following I<ctrl>s are supported in CCM mode. |
e4bbee96 | 447 | |
8fa4d95e | 448 | =over 4 |
aa714f3a | 449 | |
8fa4d95e | 450 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag) |
aa714f3a | 451 | |
8fa4d95e RT |
452 | This call is made to set the expected B<CCM> tag value when decrypting or |
453 | the length of the tag (with the C<tag> parameter set to NULL) when encrypting. | |
454 | The tag length is often referred to as B<M>. If not set a default value is | |
67c81ec3 TN |
455 | used (12 for AES). When decrypting, the tag needs to be set before passing |
456 | in data to be decrypted, but as in GCM and OCB mode, it can be set after | |
457 | passing additional authenticated data (see L<AEAD Interface>). | |
aa714f3a | 458 | |
8fa4d95e | 459 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL) |
625b9d6b | 460 | |
8fa4d95e | 461 | Sets the CCM B<L> value. If not set a default is used (8 for AES). |
625b9d6b | 462 | |
8fa4d95e | 463 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) |
625b9d6b | 464 | |
8fa4d95e RT |
465 | Sets the CCM nonce (IV) length. This call can only be made before specifying an |
466 | nonce value. The nonce length is given by B<15 - L> so it is 7 by default for | |
467 | AES. | |
625b9d6b | 468 | |
a91dedca DSH |
469 | =back |
470 | ||
b1ceb439 TS |
471 | =head2 SIV Mode |
472 | ||
473 | For SIV mode ciphers the behaviour of the EVP interface is subtly | |
474 | altered and several additional ctrl operations are supported. | |
475 | ||
476 | To specify any additional authenticated data (AAD) and/or a Nonce, a call to | |
477 | EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made | |
478 | with the output parameter B<out> set to B<NULL>. | |
479 | ||
480 | RFC5297 states that the Nonce is the last piece of AAD before the actual | |
481 | encrypt/decrypt takes place. The API does not differentiate the Nonce from | |
482 | other AAD. | |
483 | ||
484 | When decrypting the return value of EVP_DecryptFinal() or EVP_CipherFinal() | |
485 | indicates if the operation was successful. If it does not indicate success | |
486 | the authentication operation has failed and any output data B<MUST NOT> | |
487 | be used as it is corrupted. | |
488 | ||
489 | The following ctrls are supported in both SIV modes. | |
490 | ||
491 | =over 4 | |
492 | ||
493 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag); | |
494 | ||
495 | Writes B<taglen> bytes of the tag value to the buffer indicated by B<tag>. | |
496 | This call can only be made when encrypting data and B<after> all data has been | |
497 | processed (e.g. after an EVP_EncryptFinal() call). For SIV mode the taglen must | |
498 | be 16. | |
499 | ||
500 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag); | |
501 | ||
502 | Sets the expected tag to B<taglen> bytes from B<tag>. This call is only legal | |
503 | when decrypting data and must be made B<before> any data is processed (e.g. | |
504 | before any EVP_DecryptUpdate() call). For SIV mode the taglen must be 16. | |
505 | ||
506 | =back | |
507 | ||
508 | SIV mode makes two passes over the input data, thus, only one call to | |
509 | EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made | |
510 | with B<out> set to a non-B<NULL> value. A call to EVP_Decrypt_Final() or | |
511 | EVP_CipherFinal() is not required, but will indicate if the update | |
512 | operation succeeded. | |
513 | ||
8fa4d95e | 514 | =head2 ChaCha20-Poly1305 |
aa714f3a | 515 | |
8fa4d95e | 516 | The following I<ctrl>s are supported for the ChaCha20-Poly1305 AEAD algorithm. |
aa714f3a | 517 | |
8fa4d95e | 518 | =over 4 |
aa714f3a | 519 | |
8fa4d95e | 520 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL) |
aa714f3a | 521 | |
8fa4d95e RT |
522 | Sets the nonce length. This call can only be made before specifying the nonce. |
523 | If not called a default nonce length of 12 (i.e. 96 bits) is used. The maximum | |
27d56312 MC |
524 | nonce length is 12 bytes (i.e. 96-bits). If a nonce of less than 12 bytes is set |
525 | then the nonce is automatically padded with leading 0 bytes to make it 12 bytes | |
526 | in length. | |
c7497f34 | 527 | |
8fa4d95e | 528 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag) |
aa714f3a | 529 | |
8fa4d95e | 530 | Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>. |
aa714f3a | 531 | This call can only be made when encrypting data and B<after> all data has been |
8fa4d95e | 532 | processed (e.g. after an EVP_EncryptFinal() call). |
c7497f34 | 533 | |
8fa4d95e RT |
534 | C<taglen> specified here must be 16 (B<POLY1305_BLOCK_SIZE>, i.e. 128-bits) or |
535 | less. | |
aa714f3a | 536 | |
8fa4d95e | 537 | =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag) |
aa714f3a | 538 | |
8fa4d95e RT |
539 | Sets the expected tag to C<taglen> bytes from C<tag>. |
540 | The tag length can only be set before specifying an IV. | |
541 | C<taglen> must be between 1 and 16 (B<POLY1305_BLOCK_SIZE>) inclusive. | |
542 | This call is only valid when decrypting data. | |
aa714f3a | 543 | |
8fa4d95e | 544 | =back |
aa714f3a | 545 | |
72b60351 DSH |
546 | =head1 NOTES |
547 | ||
548 | Where possible the B<EVP> interface to symmetric ciphers should be used in | |
549 | preference to the low level interfaces. This is because the code then becomes | |
75b76068 JW |
550 | transparent to the cipher used and much more flexible. Additionally, the |
551 | B<EVP> interface will ensure the use of platform specific cryptographic | |
552 | acceleration such as AES-NI (the low level interfaces do not provide the | |
553 | guarantee). | |
72b60351 | 554 | |
c7497f34 | 555 | PKCS padding works by adding B<n> padding bytes of value B<n> to make the total |
72b60351 DSH |
556 | length of the encrypted data a multiple of the block size. Padding is always |
557 | added so if the data is already a multiple of the block size B<n> will equal | |
558 | the block size. For example if the block size is 8 and 11 bytes are to be | |
559 | encrypted then 5 padding bytes of value 5 will be added. | |
560 | ||
561 | When decrypting the final block is checked to see if it has the correct form. | |
562 | ||
f2e5ca84 DSH |
563 | Although the decryption operation can produce an error if padding is enabled, |
564 | it is not a strong test that the input data or key is correct. A random block | |
565 | has better than 1 in 256 chance of being of the correct format and problems with | |
566 | the input data earlier on will not produce a final decrypt error. | |
567 | ||
568 | If padding is disabled then the decryption operation will always succeed if | |
569 | the total amount of data decrypted is a multiple of the block size. | |
72b60351 | 570 | |
3811eed8 DSH |
571 | The functions EVP_EncryptInit(), EVP_EncryptFinal(), EVP_DecryptInit(), |
572 | EVP_CipherInit() and EVP_CipherFinal() are obsolete but are retained for | |
573 | compatibility with existing code. New code should use EVP_EncryptInit_ex(), | |
574 | EVP_EncryptFinal_ex(), EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(), | |
575 | EVP_CipherInit_ex() and EVP_CipherFinal_ex() because they can reuse an | |
576 | existing context without allocating and freeing it up on each call. | |
a91dedca | 577 | |
91da5e77 RS |
578 | EVP_get_cipherbynid(), and EVP_get_cipherbyobj() are implemented as macros. |
579 | ||
72b60351 DSH |
580 | =head1 BUGS |
581 | ||
8fa4d95e RT |
582 | B<EVP_MAX_KEY_LENGTH> and B<EVP_MAX_IV_LENGTH> only refer to the internal |
583 | ciphers with default key lengths. If custom ciphers exceed these values the | |
584 | results are unpredictable. This is because it has become standard practice to | |
585 | define a generic key as a fixed unsigned char array containing | |
586 | B<EVP_MAX_KEY_LENGTH> bytes. | |
a91dedca | 587 | |
c8973693 | 588 | The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested |
a91dedca DSH |
589 | for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode. |
590 | ||
591 | =head1 EXAMPLES | |
592 | ||
fd4592be | 593 | Encrypt a string using IDEA: |
18135561 DSH |
594 | |
595 | int do_crypt(char *outfile) | |
2947af32 BB |
596 | { |
597 | unsigned char outbuf[1024]; | |
598 | int outlen, tmplen; | |
599 | /* | |
600 | * Bogus key and IV: we'd normally set these from | |
601 | * another source. | |
602 | */ | |
603 | unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; | |
604 | unsigned char iv[] = {1,2,3,4,5,6,7,8}; | |
605 | char intext[] = "Some Crypto Text"; | |
606 | EVP_CIPHER_CTX *ctx; | |
607 | FILE *out; | |
608 | ||
609 | ctx = EVP_CIPHER_CTX_new(); | |
610 | EVP_EncryptInit_ex(ctx, EVP_idea_cbc(), NULL, key, iv); | |
611 | ||
612 | if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) { | |
613 | /* Error */ | |
519a5d1e | 614 | EVP_CIPHER_CTX_free(ctx); |
2947af32 BB |
615 | return 0; |
616 | } | |
617 | /* | |
618 | * Buffer passed to EVP_EncryptFinal() must be after data just | |
619 | * encrypted to avoid overwriting it. | |
620 | */ | |
621 | if (!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) { | |
622 | /* Error */ | |
519a5d1e | 623 | EVP_CIPHER_CTX_free(ctx); |
2947af32 BB |
624 | return 0; |
625 | } | |
626 | outlen += tmplen; | |
627 | EVP_CIPHER_CTX_free(ctx); | |
628 | /* | |
629 | * Need binary mode for fopen because encrypted data is | |
630 | * binary data. Also cannot use strlen() on it because | |
631 | * it won't be NUL terminated and may contain embedded | |
632 | * NULs. | |
633 | */ | |
634 | out = fopen(outfile, "wb"); | |
519a5d1e GZ |
635 | if (out == NULL) { |
636 | /* Error */ | |
637 | return 0; | |
638 | } | |
2947af32 BB |
639 | fwrite(outbuf, 1, outlen, out); |
640 | fclose(out); | |
641 | return 1; | |
642 | } | |
18135561 DSH |
643 | |
644 | The ciphertext from the above example can be decrypted using the B<openssl> | |
fd4592be | 645 | utility with the command line (shown on two lines for clarity): |
c7497f34 | 646 | |
2947af32 BB |
647 | openssl idea -d \ |
648 | -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 <filename | |
18135561 | 649 | |
fd4592be JS |
650 | General encryption and decryption function example using FILE I/O and AES128 |
651 | with a 128-bit key: | |
18135561 DSH |
652 | |
653 | int do_crypt(FILE *in, FILE *out, int do_encrypt) | |
2947af32 BB |
654 | { |
655 | /* Allow enough space in output buffer for additional block */ | |
656 | unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH]; | |
657 | int inlen, outlen; | |
658 | EVP_CIPHER_CTX *ctx; | |
659 | /* | |
660 | * Bogus key and IV: we'd normally set these from | |
661 | * another source. | |
662 | */ | |
663 | unsigned char key[] = "0123456789abcdeF"; | |
664 | unsigned char iv[] = "1234567887654321"; | |
665 | ||
666 | /* Don't set key or IV right away; we want to check lengths */ | |
667 | ctx = EVP_CIPHER_CTX_new(); | |
668 | EVP_CipherInit_ex(&ctx, EVP_aes_128_cbc(), NULL, NULL, NULL, | |
669 | do_encrypt); | |
670 | OPENSSL_assert(EVP_CIPHER_CTX_key_length(ctx) == 16); | |
671 | OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) == 16); | |
672 | ||
673 | /* Now we can set key and IV */ | |
674 | EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, do_encrypt); | |
675 | ||
676 | for (;;) { | |
677 | inlen = fread(inbuf, 1, 1024, in); | |
678 | if (inlen <= 0) | |
679 | break; | |
680 | if (!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) { | |
681 | /* Error */ | |
682 | EVP_CIPHER_CTX_free(ctx); | |
683 | return 0; | |
684 | } | |
685 | fwrite(outbuf, 1, outlen, out); | |
686 | } | |
687 | if (!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) { | |
688 | /* Error */ | |
689 | EVP_CIPHER_CTX_free(ctx); | |
690 | return 0; | |
691 | } | |
692 | fwrite(outbuf, 1, outlen, out); | |
693 | ||
694 | EVP_CIPHER_CTX_free(ctx); | |
695 | return 1; | |
696 | } | |
18135561 DSH |
697 | |
698 | ||
72b60351 DSH |
699 | =head1 SEE ALSO |
700 | ||
b97fdb57 | 701 | L<evp(7)> |
72b60351 | 702 | |
8fa4d95e RT |
703 | Supported ciphers are listed in: |
704 | ||
705 | L<EVP_aes(3)>, | |
706 | L<EVP_aria(3)>, | |
707 | L<EVP_bf(3)>, | |
708 | L<EVP_camellia(3)>, | |
709 | L<EVP_cast5(3)>, | |
710 | L<EVP_chacha20(3)>, | |
711 | L<EVP_des(3)>, | |
712 | L<EVP_desx(3)>, | |
713 | L<EVP_idea(3)>, | |
714 | L<EVP_rc2(3)>, | |
715 | L<EVP_rc4(3)>, | |
716 | L<EVP_rc5(3)>, | |
717 | L<EVP_seed(3)>, | |
718 | L<EVP_sm4(3)> | |
719 | ||
72b60351 DSH |
720 | =head1 HISTORY |
721 | ||
fc5ecadd | 722 | Support for OCB mode was added in OpenSSL 1.1.0. |
a528d4f0 | 723 | |
05fdb8d3 RL |
724 | B<EVP_CIPHER_CTX> was made opaque in OpenSSL 1.1.0. As a result, |
725 | EVP_CIPHER_CTX_reset() appeared and EVP_CIPHER_CTX_cleanup() | |
726 | disappeared. EVP_CIPHER_CTX_init() remains as an alias for | |
727 | EVP_CIPHER_CTX_reset(). | |
728 | ||
e2f92610 RS |
729 | =head1 COPYRIGHT |
730 | ||
0d664759 | 731 | Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 | 732 | |
4746f25a | 733 | Licensed under the Apache License 2.0 (the "License"). You may not use |
e2f92610 RS |
734 | this file except in compliance with the License. You can obtain a copy |
735 | in the file LICENSE in the source distribution or at | |
736 | L<https://www.openssl.org/source/license.html>. | |
737 | ||
738 | =cut |