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Commit | Line | Data |
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72b60351 DSH |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
05fdb8d3 RL |
5 | EVP_CIPHER_CTX_new, EVP_CIPHER_CTX_reset, EVP_CIPHER_CTX_free, |
6 | EVP_EncryptInit_ex, EVP_EncryptUpdate, EVP_EncryptFinal_ex, | |
7 | EVP_DecryptInit_ex, EVP_DecryptUpdate, EVP_DecryptFinal_ex, | |
8 | EVP_CipherInit_ex, EVP_CipherUpdate, EVP_CipherFinal_ex, | |
9 | EVP_CIPHER_CTX_set_key_length, EVP_CIPHER_CTX_ctrl, EVP_EncryptInit, | |
3811eed8 DSH |
10 | EVP_EncryptFinal, EVP_DecryptInit, EVP_DecryptFinal, |
11 | EVP_CipherInit, EVP_CipherFinal, EVP_get_cipherbyname, | |
12 | EVP_get_cipherbynid, EVP_get_cipherbyobj, EVP_CIPHER_nid, | |
13 | EVP_CIPHER_block_size, EVP_CIPHER_key_length, EVP_CIPHER_iv_length, | |
14 | EVP_CIPHER_flags, EVP_CIPHER_mode, EVP_CIPHER_type, EVP_CIPHER_CTX_cipher, | |
15 | EVP_CIPHER_CTX_nid, EVP_CIPHER_CTX_block_size, EVP_CIPHER_CTX_key_length, | |
16 | EVP_CIPHER_CTX_iv_length, EVP_CIPHER_CTX_get_app_data, | |
17 | EVP_CIPHER_CTX_set_app_data, EVP_CIPHER_CTX_type, EVP_CIPHER_CTX_flags, | |
18 | EVP_CIPHER_CTX_mode, EVP_CIPHER_param_to_asn1, EVP_CIPHER_asn1_to_param, | |
0517ffc4 | 19 | EVP_CIPHER_CTX_set_padding, EVP_enc_null, EVP_des_cbc, EVP_des_ecb, |
aafbe1cc MC |
20 | EVP_des_cfb, EVP_des_ofb, EVP_des_ede_cbc, EVP_des_ede, EVP_des_ede_ofb, |
21 | EVP_des_ede_cfb, EVP_des_ede3_cbc, EVP_des_ede3, EVP_des_ede3_ofb, | |
22 | EVP_des_ede3_cfb, EVP_desx_cbc, EVP_rc4, EVP_rc4_40, EVP_idea_cbc, | |
e03af178 | 23 | EVP_idea_ecb, EVP_idea_cfb, EVP_idea_ofb, EVP_rc2_cbc, |
aafbe1cc MC |
24 | EVP_rc2_ecb, EVP_rc2_cfb, EVP_rc2_ofb, EVP_rc2_40_cbc, EVP_rc2_64_cbc, |
25 | EVP_bf_cbc, EVP_bf_ecb, EVP_bf_cfb, EVP_bf_ofb, EVP_cast5_cbc, | |
26 | EVP_cast5_ecb, EVP_cast5_cfb, EVP_cast5_ofb, EVP_rc5_32_12_16_cbc, | |
c7497f34 RS |
27 | EVP_rc5_32_12_16_ecb, EVP_rc5_32_12_16_cfb, EVP_rc5_32_12_16_ofb, |
28 | EVP_aes_128_cbc, EVP_aes_128_ecb, EVP_aes_128_cfb, EVP_aes_128_ofb, | |
29 | EVP_aes_192_cbc, EVP_aes_192_ecb, EVP_aes_192_cfb, EVP_aes_192_ofb, | |
30 | EVP_aes_256_cbc, EVP_aes_256_ecb, EVP_aes_256_cfb, EVP_aes_256_ofb, | |
31 | EVP_aes_128_gcm, EVP_aes_192_gcm, EVP_aes_256_gcm, | |
32 | EVP_aes_128_ccm, EVP_aes_192_ccm, EVP_aes_256_ccm - EVP cipher routines | |
72b60351 | 33 | |
c952780c RS |
34 | =for comment generic |
35 | ||
72b60351 DSH |
36 | =head1 SYNOPSIS |
37 | ||
38 | #include <openssl/evp.h> | |
39 | ||
05fdb8d3 RL |
40 | EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void); |
41 | int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx); | |
42 | void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx); | |
3811eed8 DSH |
43 | |
44 | int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
1bc74519 | 45 | ENGINE *impl, unsigned char *key, unsigned char *iv); |
a91dedca | 46 | int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
4d524e10 | 47 | int *outl, unsigned char *in, int inl); |
3811eed8 DSH |
48 | int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, |
49 | int *outl); | |
50 | ||
51 | int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
1bc74519 | 52 | ENGINE *impl, unsigned char *key, unsigned char *iv); |
3811eed8 DSH |
53 | int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, |
54 | int *outl, unsigned char *in, int inl); | |
55 | int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, | |
56 | int *outl); | |
57 | ||
58 | int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
59 | ENGINE *impl, unsigned char *key, unsigned char *iv, int enc); | |
60 | int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, | |
61 | int *outl, unsigned char *in, int inl); | |
62 | int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, | |
63 | int *outl); | |
64 | ||
65 | int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, | |
66 | unsigned char *key, unsigned char *iv); | |
a91dedca | 67 | int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, |
4d524e10 UM |
68 | int *outl); |
69 | ||
a91dedca | 70 | int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, |
4d524e10 | 71 | unsigned char *key, unsigned char *iv); |
4d524e10 UM |
72 | int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, |
73 | int *outl); | |
74 | ||
a91dedca | 75 | int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, |
4d524e10 | 76 | unsigned char *key, unsigned char *iv, int enc); |
4d524e10 UM |
77 | int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, |
78 | int *outl); | |
72b60351 | 79 | |
f2e5ca84 | 80 | int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding); |
a91dedca DSH |
81 | int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen); |
82 | int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr); | |
72b60351 DSH |
83 | |
84 | const EVP_CIPHER *EVP_get_cipherbyname(const char *name); | |
85 | #define EVP_get_cipherbynid(a) EVP_get_cipherbyname(OBJ_nid2sn(a)) | |
86 | #define EVP_get_cipherbyobj(a) EVP_get_cipherbynid(OBJ_obj2nid(a)) | |
87 | ||
1bc74519 RS |
88 | #define EVP_CIPHER_nid(e) ((e)->nid) |
89 | #define EVP_CIPHER_block_size(e) ((e)->block_size) | |
90 | #define EVP_CIPHER_key_length(e) ((e)->key_len) | |
91 | #define EVP_CIPHER_iv_length(e) ((e)->iv_len) | |
92 | #define EVP_CIPHER_flags(e) ((e)->flags) | |
93 | #define EVP_CIPHER_mode(e) ((e)->flags) & EVP_CIPH_MODE) | |
72b60351 | 94 | int EVP_CIPHER_type(const EVP_CIPHER *ctx); |
a91dedca | 95 | |
05fdb8d3 RL |
96 | const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *ctx); |
97 | int EVP_CIPHER_CTX_nid(const EVP_CIPHER_CTX *ctx); | |
98 | int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *ctx); | |
99 | int EVP_CIPHER_CTX_key_length(const EVP_CIPHER_CTX *ctx); | |
100 | int EVP_CIPHER_CTX_iv_length(const EVP_CIPHER_CTX *ctx); | |
101 | void *EVP_CIPHER_CTX_get_app_data(const EVP_CIPHER_CTX *ctx); | |
102 | void EVP_CIPHER_CTX_set_app_data(const EVP_CIPHER_CTX *ctx, void *data); | |
103 | int EVP_CIPHER_CTX_type(const EVP_CIPHER_CTX *ctx); | |
05fdb8d3 | 104 | int EVP_CIPHER_CTX_mode(const EVP_CIPHER_CTX *ctx); |
72b60351 | 105 | |
3f2b5a88 DSH |
106 | int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type); |
107 | int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type); | |
108 | ||
72b60351 DSH |
109 | =head1 DESCRIPTION |
110 | ||
111 | The EVP cipher routines are a high level interface to certain | |
112 | symmetric ciphers. | |
113 | ||
05fdb8d3 RL |
114 | EVP_CIPHER_CTX_new() creates a cipher context. |
115 | ||
116 | EVP_CIPHER_CTX_free() clears all information from a cipher context | |
117 | and free up any allocated memory associate with it, including B<ctx> | |
118 | itself. This function should be called after all operations using a | |
119 | cipher are complete so sensitive information does not remain in | |
120 | memory. | |
3811eed8 DSH |
121 | |
122 | EVP_EncryptInit_ex() sets up cipher context B<ctx> for encryption | |
05fdb8d3 | 123 | with cipher B<type> from ENGINE B<impl>. B<ctx> must be created |
3811eed8 | 124 | before calling this function. B<type> is normally supplied |
740ceb5b | 125 | by a function such as EVP_aes_256_cbc(). If B<impl> is NULL then the |
3811eed8 DSH |
126 | default implementation is used. B<key> is the symmetric key to use |
127 | and B<iv> is the IV to use (if necessary), the actual number of bytes | |
128 | used for the key and IV depends on the cipher. It is possible to set | |
129 | all parameters to NULL except B<type> in an initial call and supply | |
130 | the remaining parameters in subsequent calls, all of which have B<type> | |
131 | set to NULL. This is done when the default cipher parameters are not | |
132 | appropriate. | |
72b60351 DSH |
133 | |
134 | EVP_EncryptUpdate() encrypts B<inl> bytes from the buffer B<in> and | |
135 | writes the encrypted version to B<out>. This function can be called | |
136 | multiple times to encrypt successive blocks of data. The amount | |
137 | of data written depends on the block alignment of the encrypted data: | |
138 | as a result the amount of data written may be anything from zero bytes | |
5211e094 | 139 | to (inl + cipher_block_size - 1) so B<out> should contain sufficient |
c3a73daf AP |
140 | room. The actual number of bytes written is placed in B<outl>. It also |
141 | checks if B<in> and B<out> are partially overlapping, and if they are | |
142 | 0 is returned to indicate failure. | |
72b60351 | 143 | |
3811eed8 | 144 | If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts |
f2e5ca84 | 145 | the "final" data, that is any data that remains in a partial block. |
a09474dd RS |
146 | It uses standard block padding (aka PKCS padding) as described in |
147 | the NOTES section, below. The encrypted | |
f2e5ca84 DSH |
148 | final data is written to B<out> which should have sufficient space for |
149 | one cipher block. The number of bytes written is placed in B<outl>. After | |
150 | this function is called the encryption operation is finished and no further | |
151 | calls to EVP_EncryptUpdate() should be made. | |
152 | ||
3811eed8 | 153 | If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more |
f2e5ca84 | 154 | data and it will return an error if any data remains in a partial block: |
c7497f34 | 155 | that is if the total data length is not a multiple of the block size. |
72b60351 | 156 | |
3811eed8 | 157 | EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex() are the |
72b60351 | 158 | corresponding decryption operations. EVP_DecryptFinal() will return an |
f2e5ca84 DSH |
159 | error code if padding is enabled and the final block is not correctly |
160 | formatted. The parameters and restrictions are identical to the encryption | |
161 | operations except that if padding is enabled the decrypted data buffer B<out> | |
162 | passed to EVP_DecryptUpdate() should have sufficient room for | |
163 | (B<inl> + cipher_block_size) bytes unless the cipher block size is 1 in | |
164 | which case B<inl> bytes is sufficient. | |
72b60351 | 165 | |
3811eed8 DSH |
166 | EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex() are |
167 | functions that can be used for decryption or encryption. The operation | |
168 | performed depends on the value of the B<enc> parameter. It should be set | |
169 | to 1 for encryption, 0 for decryption and -1 to leave the value unchanged | |
170 | (the actual value of 'enc' being supplied in a previous call). | |
171 | ||
05fdb8d3 RL |
172 | EVP_CIPHER_CTX_reset() clears all information from a cipher context |
173 | and free up any allocated memory associate with it, except the B<ctx> | |
174 | itself. This function should be called anytime B<ctx> is to be reused | |
175 | for another EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal() | |
176 | series of calls. | |
3811eed8 DSH |
177 | |
178 | EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit() behave in a | |
d4a43700 | 179 | similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and |
2b4ffc65 | 180 | EVP_CipherInit_ex() except the B<ctx> parameter does not need to be |
3811eed8 | 181 | initialized and they always use the default cipher implementation. |
72b60351 | 182 | |
538860a3 RS |
183 | EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() are |
184 | identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and | |
185 | EVP_CipherFinal_ex(). In previous releases they also cleaned up | |
186 | the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean() | |
187 | must be called to free any context resources. | |
72b60351 | 188 | |
3f2b5a88 DSH |
189 | EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() |
190 | return an EVP_CIPHER structure when passed a cipher name, a NID or an | |
191 | ASN1_OBJECT structure. | |
192 | ||
193 | EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return the NID of a cipher when | |
194 | passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> structure. The actual NID | |
195 | value is an internal value which may not have a corresponding OBJECT | |
196 | IDENTIFIER. | |
197 | ||
83f68df3 CPLG |
198 | EVP_CIPHER_CTX_set_padding() enables or disables padding. This |
199 | function should be called after the context is set up for encryption | |
200 | or decryption with EVP_EncryptInit_ex(), EVP_DecryptInit_ex() or | |
201 | EVP_CipherInit_ex(). By default encryption operations are padded using | |
202 | standard block padding and the padding is checked and removed when | |
203 | decrypting. If the B<pad> parameter is zero then no padding is | |
204 | performed, the total amount of data encrypted or decrypted must then | |
205 | be a multiple of the block size or an error will occur. | |
f2e5ca84 | 206 | |
3f2b5a88 DSH |
207 | EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key |
208 | length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> | |
209 | structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum key length | |
a91dedca DSH |
210 | for all ciphers. Note: although EVP_CIPHER_key_length() is fixed for a |
211 | given cipher, the value of EVP_CIPHER_CTX_key_length() may be different | |
212 | for variable key length ciphers. | |
213 | ||
214 | EVP_CIPHER_CTX_set_key_length() sets the key length of the cipher ctx. | |
215 | If the cipher is a fixed length cipher then attempting to set the key | |
216 | length to any value other than the fixed value is an error. | |
3f2b5a88 DSH |
217 | |
218 | EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV | |
219 | length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>. | |
220 | It will return zero if the cipher does not use an IV. The constant | |
221 | B<EVP_MAX_IV_LENGTH> is the maximum IV length for all ciphers. | |
222 | ||
223 | EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block | |
224 | size of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> | |
14f46560 | 225 | structure. The constant B<EVP_MAX_BLOCK_LENGTH> is also the maximum block |
3f2b5a88 DSH |
226 | length for all ciphers. |
227 | ||
228 | EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the type of the passed | |
229 | cipher or context. This "type" is the actual NID of the cipher OBJECT | |
230 | IDENTIFIER as such it ignores the cipher parameters and 40 bit RC2 and | |
41e68ef2 DSH |
231 | 128 bit RC2 have the same NID. If the cipher does not have an object |
232 | identifier or does not have ASN1 support this function will return | |
233 | B<NID_undef>. | |
3f2b5a88 DSH |
234 | |
235 | EVP_CIPHER_CTX_cipher() returns the B<EVP_CIPHER> structure when passed | |
236 | an B<EVP_CIPHER_CTX> structure. | |
237 | ||
a91dedca DSH |
238 | EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return the block cipher mode: |
239 | EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE or | |
240 | EVP_CIPH_OFB_MODE. If the cipher is a stream cipher then | |
241 | EVP_CIPH_STREAM_CIPHER is returned. | |
242 | ||
3f2b5a88 DSH |
243 | EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter" based |
244 | on the passed cipher. This will typically include any parameters and an | |
245 | IV. The cipher IV (if any) must be set when this call is made. This call | |
246 | should be made before the cipher is actually "used" (before any | |
247 | EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example). This function | |
248 | may fail if the cipher does not have any ASN1 support. | |
249 | ||
250 | EVP_CIPHER_asn1_to_param() sets the cipher parameters based on an ASN1 | |
251 | AlgorithmIdentifier "parameter". The precise effect depends on the cipher | |
252 | In the case of RC2, for example, it will set the IV and effective key length. | |
253 | This function should be called after the base cipher type is set but before | |
254 | the key is set. For example EVP_CipherInit() will be called with the IV and | |
255 | key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally | |
256 | EVP_CipherInit() again with all parameters except the key set to NULL. It is | |
257 | possible for this function to fail if the cipher does not have any ASN1 support | |
258 | or the parameters cannot be set (for example the RC2 effective key length | |
a91dedca DSH |
259 | is not supported. |
260 | ||
261 | EVP_CIPHER_CTX_ctrl() allows various cipher specific parameters to be determined | |
aa714f3a | 262 | and set. |
3f2b5a88 | 263 | |
72b60351 DSH |
264 | =head1 RETURN VALUES |
265 | ||
05fdb8d3 RL |
266 | EVP_CIPHER_CTX_new() returns a pointer to a newly created |
267 | B<EVP_CIPHER_CTX> for success and B<NULL> for failure. | |
268 | ||
0e304b7f NL |
269 | EVP_EncryptInit_ex(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex() |
270 | return 1 for success and 0 for failure. | |
72b60351 | 271 | |
3811eed8 DSH |
272 | EVP_DecryptInit_ex() and EVP_DecryptUpdate() return 1 for success and 0 for failure. |
273 | EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success. | |
72b60351 | 274 | |
3811eed8 | 275 | EVP_CipherInit_ex() and EVP_CipherUpdate() return 1 for success and 0 for failure. |
21d5ed98 | 276 | EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success. |
72b60351 | 277 | |
05fdb8d3 | 278 | EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure. |
3f2b5a88 DSH |
279 | |
280 | EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj() | |
281 | return an B<EVP_CIPHER> structure or NULL on error. | |
282 | ||
283 | EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return a NID. | |
284 | ||
285 | EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block | |
286 | size. | |
287 | ||
288 | EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key | |
289 | length. | |
290 | ||
f2e5ca84 DSH |
291 | EVP_CIPHER_CTX_set_padding() always returns 1. |
292 | ||
3f2b5a88 DSH |
293 | EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV |
294 | length or zero if the cipher does not use an IV. | |
295 | ||
41e68ef2 DSH |
296 | EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the NID of the cipher's |
297 | OBJECT IDENTIFIER or NID_undef if it has no defined OBJECT IDENTIFIER. | |
298 | ||
299 | EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure. | |
300 | ||
c03726ca RS |
301 | EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater |
302 | than zero for success and zero or a negative number. | |
41e68ef2 | 303 | |
a91dedca DSH |
304 | =head1 CIPHER LISTING |
305 | ||
306 | All algorithms have a fixed key length unless otherwise stated. | |
307 | ||
308 | =over 4 | |
309 | ||
310 | =item EVP_enc_null() | |
311 | ||
312 | Null cipher: does nothing. | |
313 | ||
c7497f34 | 314 | =item EVP_aes_128_cbc(), EVP_aes_128_ecb(), EVP_aes_128_cfb(), EVP_aes_128_ofb() |
a91dedca | 315 | |
c7497f34 | 316 | AES with a 128-bit key in CBC, ECB, CFB and OFB modes respectively. |
a91dedca | 317 | |
c7497f34 RS |
318 | =item EVP_aes_192_cbc(), EVP_aes_192_ecb(), EVP_aes_192_cfb(), EVP_aes_192_ofb() |
319 | ||
320 | AES with a 192-bit key in CBC, ECB, CFB and OFB modes respectively. | |
321 | ||
322 | =item EVP_aes_256_cbc(), EVP_aes_256_ecb(), EVP_aes_256_cfb(), EVP_aes_256_ofb() | |
323 | ||
324 | AES with a 256-bit key in CBC, ECB, CFB and OFB modes respectively. | |
325 | ||
326 | =item EVP_des_cbc(), EVP_des_ecb(), EVP_des_cfb(), EVP_des_ofb() | |
327 | ||
328 | DES in CBC, ECB, CFB and OFB modes respectively. | |
329 | ||
0517ffc4 | 330 | =item EVP_des_ede_cbc(), EVP_des_ede(), EVP_des_ede_ofb(), EVP_des_ede_cfb() |
a91dedca DSH |
331 | |
332 | Two key triple DES in CBC, ECB, CFB and OFB modes respectively. | |
333 | ||
0517ffc4 | 334 | =item EVP_des_ede3_cbc(), EVP_des_ede3(), EVP_des_ede3_ofb(), EVP_des_ede3_cfb() |
a91dedca DSH |
335 | |
336 | Three key triple DES in CBC, ECB, CFB and OFB modes respectively. | |
337 | ||
c7497f34 | 338 | =item EVP_desx_cbc() |
a91dedca DSH |
339 | |
340 | DESX algorithm in CBC mode. | |
341 | ||
c7497f34 | 342 | =item EVP_rc4() |
a91dedca DSH |
343 | |
344 | RC4 stream cipher. This is a variable key length cipher with default key length 128 bits. | |
345 | ||
c7497f34 | 346 | =item EVP_rc4_40() |
a91dedca | 347 | |
c7497f34 RS |
348 | RC4 stream cipher with 40 bit key length. |
349 | This is obsolete and new code should use EVP_rc4() | |
a91dedca DSH |
350 | and the EVP_CIPHER_CTX_set_key_length() function. |
351 | ||
e03af178 | 352 | =item EVP_idea_cbc() EVP_idea_ecb(), EVP_idea_cfb(), EVP_idea_ofb() |
a91dedca | 353 | |
c8973693 | 354 | IDEA encryption algorithm in CBC, ECB, CFB and OFB modes respectively. |
a91dedca | 355 | |
c7497f34 | 356 | =item EVP_rc2_cbc(), EVP_rc2_ecb(), EVP_rc2_cfb(), EVP_rc2_ofb() |
a91dedca DSH |
357 | |
358 | RC2 encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key | |
359 | length cipher with an additional parameter called "effective key bits" or "effective key length". | |
360 | By default both are set to 128 bits. | |
361 | ||
c7497f34 | 362 | =item EVP_rc2_40_cbc(), EVP_rc2_64_cbc() |
a91dedca DSH |
363 | |
364 | RC2 algorithm in CBC mode with a default key length and effective key length of 40 and 64 bits. | |
365 | These are obsolete and new code should use EVP_rc2_cbc(), EVP_CIPHER_CTX_set_key_length() and | |
366 | EVP_CIPHER_CTX_ctrl() to set the key length and effective key length. | |
367 | ||
c7497f34 | 368 | =item EVP_bf_cbc(), EVP_bf_ecb(), EVP_bf_cfb(), EVP_bf_ofb() |
a91dedca DSH |
369 | |
370 | Blowfish encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key | |
371 | length cipher. | |
372 | ||
c7497f34 | 373 | =item EVP_cast5_cbc(), EVP_cast5_ecb(), EVP_cast5_cfb(), EVP_cast5_ofb() |
a91dedca DSH |
374 | |
375 | CAST encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key | |
376 | length cipher. | |
377 | ||
c7497f34 | 378 | =item EVP_rc5_32_12_16_cbc(), EVP_rc5_32_12_16_ecb(), EVP_rc5_32_12_16_cfb(), EVP_rc5_32_12_16_ofb() |
a91dedca DSH |
379 | |
380 | RC5 encryption algorithm in CBC, ECB, CFB and OFB modes respectively. This is a variable key length | |
381 | cipher with an additional "number of rounds" parameter. By default the key length is set to 128 | |
382 | bits and 12 rounds. | |
383 | ||
c7497f34 | 384 | =item EVP_aes_128_gcm(), EVP_aes_192_gcm(), EVP_aes_256_gcm() |
aa714f3a DSH |
385 | |
386 | AES Galois Counter Mode (GCM) for 128, 192 and 256 bit keys respectively. | |
387 | These ciphers require additional control operations to function correctly: see | |
1bc74519 | 388 | the L</GCM and OCB Modes> section below for details. |
e4bbee96 MC |
389 | |
390 | =item EVP_aes_128_ocb(void), EVP_aes_192_ocb(void), EVP_aes_256_ocb(void) | |
391 | ||
8483a003 | 392 | Offset Codebook Mode (OCB) for 128, 192 and 256 bit keys respectively. |
e4bbee96 | 393 | These ciphers require additional control operations to function correctly: see |
1bc74519 | 394 | the L</GCM and OCB Modes> section below for details. |
aa714f3a | 395 | |
c7497f34 | 396 | =item EVP_aes_128_ccm(), EVP_aes_192_ccm(), EVP_aes_256_ccm() |
aa714f3a DSH |
397 | |
398 | AES Counter with CBC-MAC Mode (CCM) for 128, 192 and 256 bit keys respectively. | |
399 | These ciphers require additional control operations to function correctly: see | |
400 | CCM mode section below for details. | |
401 | ||
a91dedca DSH |
402 | =back |
403 | ||
e4bbee96 | 404 | =head1 GCM and OCB Modes |
aa714f3a | 405 | |
e4bbee96 MC |
406 | For GCM and OCB mode ciphers the behaviour of the EVP interface is subtly |
407 | altered and several additional ctrl operations are supported. | |
aa714f3a DSH |
408 | |
409 | To specify any additional authenticated data (AAD) a call to EVP_CipherUpdate(), | |
c7497f34 | 410 | EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output |
aa714f3a DSH |
411 | parameter B<out> set to B<NULL>. |
412 | ||
413 | When decrypting the return value of EVP_DecryptFinal() or EVP_CipherFinal() | |
414 | indicates if the operation was successful. If it does not indicate success | |
415 | the authentication operation has failed and any output data B<MUST NOT> | |
416 | be used as it is corrupted. | |
417 | ||
e4bbee96 | 418 | The following ctrls are supported in both GCM and OCB modes: |
aa714f3a | 419 | |
e640fa02 | 420 | EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL); |
aa714f3a | 421 | |
e4bbee96 MC |
422 | Sets the IV length: this call can only be made before specifying an IV. If |
423 | not called a default IV length is used. For GCM AES and OCB AES the default is | |
424 | 12 (i.e. 96 bits). For OCB mode the maximum is 15. | |
c7497f34 | 425 | |
e640fa02 | 426 | EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag); |
aa714f3a DSH |
427 | |
428 | Writes B<taglen> bytes of the tag value to the buffer indicated by B<tag>. | |
429 | This call can only be made when encrypting data and B<after> all data has been | |
e4bbee96 MC |
430 | processed (e.g. after an EVP_EncryptFinal() call). For OCB mode the taglen must |
431 | either be 16 or the value previously set via EVP_CTRL_OCB_SET_TAGLEN. | |
aa714f3a | 432 | |
e640fa02 | 433 | EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag); |
aa714f3a DSH |
434 | |
435 | Sets the expected tag to B<taglen> bytes from B<tag>. This call is only legal | |
436 | when decrypting data and must be made B<before> any data is processed (e.g. | |
e4bbee96 | 437 | before any EVP_DecryptUpdate() call). For OCB mode the taglen must |
e640fa02 MC |
438 | either be 16 or the value previously set via EVP_CTRL_AEAD_SET_TAG. |
439 | ||
440 | In OCB mode calling this with B<tag> set to NULL sets the tag length. The tag | |
441 | length can only be set before specifying an IV. If not called a default tag | |
442 | length is used. For OCB AES the default is 16 (i.e. 128 bits). This is also the | |
443 | maximum tag length for OCB. | |
aa714f3a | 444 | |
c1e35057 | 445 | See L</EXAMPLES> below for an example of the use of GCM mode. |
aa714f3a DSH |
446 | |
447 | =head1 CCM Mode | |
448 | ||
e640fa02 | 449 | The behaviour of CCM mode ciphers is similar to GCM mode but with a few |
aa714f3a DSH |
450 | additional requirements and different ctrl values. |
451 | ||
e4bbee96 | 452 | Like GCM and OCB modes any additional authenticated data (AAD) is passed by calling |
c7497f34 | 453 | EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output |
aa714f3a DSH |
454 | parameter B<out> set to B<NULL>. Additionally the total plaintext or ciphertext |
455 | length B<MUST> be passed to EVP_CipherUpdate(), EVP_EncryptUpdate() or | |
c7497f34 | 456 | EVP_DecryptUpdate() with the output and input parameters (B<in> and B<out>) |
aa714f3a DSH |
457 | set to B<NULL> and the length passed in the B<inl> parameter. |
458 | ||
459 | The following ctrls are supported in CCM mode: | |
c7497f34 | 460 | |
e640fa02 | 461 | EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag); |
aa714f3a DSH |
462 | |
463 | This call is made to set the expected B<CCM> tag value when decrypting or | |
464 | the length of the tag (with the B<tag> parameter set to NULL) when encrypting. | |
465 | The tag length is often referred to as B<M>. If not set a default value is | |
466 | used (12 for AES). | |
467 | ||
468 | EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL); | |
469 | ||
470 | Sets the CCM B<L> value. If not set a default is used (8 for AES). | |
471 | ||
e640fa02 | 472 | EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL); |
aa714f3a DSH |
473 | |
474 | Sets the CCM nonce (IV) length: this call can only be made before specifying | |
475 | an nonce value. The nonce length is given by B<15 - L> so it is 7 by default | |
476 | for AES. | |
477 | ||
478 | ||
479 | ||
72b60351 DSH |
480 | =head1 NOTES |
481 | ||
482 | Where possible the B<EVP> interface to symmetric ciphers should be used in | |
483 | preference to the low level interfaces. This is because the code then becomes | |
75b76068 JW |
484 | transparent to the cipher used and much more flexible. Additionally, the |
485 | B<EVP> interface will ensure the use of platform specific cryptographic | |
486 | acceleration such as AES-NI (the low level interfaces do not provide the | |
487 | guarantee). | |
72b60351 | 488 | |
c7497f34 | 489 | PKCS padding works by adding B<n> padding bytes of value B<n> to make the total |
72b60351 DSH |
490 | length of the encrypted data a multiple of the block size. Padding is always |
491 | added so if the data is already a multiple of the block size B<n> will equal | |
492 | the block size. For example if the block size is 8 and 11 bytes are to be | |
493 | encrypted then 5 padding bytes of value 5 will be added. | |
494 | ||
495 | When decrypting the final block is checked to see if it has the correct form. | |
496 | ||
f2e5ca84 DSH |
497 | Although the decryption operation can produce an error if padding is enabled, |
498 | it is not a strong test that the input data or key is correct. A random block | |
499 | has better than 1 in 256 chance of being of the correct format and problems with | |
500 | the input data earlier on will not produce a final decrypt error. | |
501 | ||
502 | If padding is disabled then the decryption operation will always succeed if | |
503 | the total amount of data decrypted is a multiple of the block size. | |
72b60351 | 504 | |
3811eed8 DSH |
505 | The functions EVP_EncryptInit(), EVP_EncryptFinal(), EVP_DecryptInit(), |
506 | EVP_CipherInit() and EVP_CipherFinal() are obsolete but are retained for | |
507 | compatibility with existing code. New code should use EVP_EncryptInit_ex(), | |
508 | EVP_EncryptFinal_ex(), EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(), | |
509 | EVP_CipherInit_ex() and EVP_CipherFinal_ex() because they can reuse an | |
510 | existing context without allocating and freeing it up on each call. | |
a91dedca | 511 | |
72b60351 DSH |
512 | =head1 BUGS |
513 | ||
a91dedca DSH |
514 | For RC5 the number of rounds can currently only be set to 8, 12 or 16. This is |
515 | a limitation of the current RC5 code rather than the EVP interface. | |
516 | ||
a91dedca DSH |
517 | EVP_MAX_KEY_LENGTH and EVP_MAX_IV_LENGTH only refer to the internal ciphers with |
518 | default key lengths. If custom ciphers exceed these values the results are | |
c7497f34 | 519 | unpredictable. This is because it has become standard practice to define a |
a91dedca DSH |
520 | generic key as a fixed unsigned char array containing EVP_MAX_KEY_LENGTH bytes. |
521 | ||
c8973693 | 522 | The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested |
a91dedca DSH |
523 | for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode. |
524 | ||
525 | =head1 EXAMPLES | |
526 | ||
fd4592be | 527 | Encrypt a string using IDEA: |
18135561 DSH |
528 | |
529 | int do_crypt(char *outfile) | |
1bc74519 RS |
530 | { |
531 | unsigned char outbuf[1024]; | |
532 | int outlen, tmplen; | |
533 | /* Bogus key and IV: we'd normally set these from | |
534 | * another source. | |
535 | */ | |
536 | unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; | |
537 | unsigned char iv[] = {1,2,3,4,5,6,7,8}; | |
538 | char intext[] = "Some Crypto Text"; | |
539 | EVP_CIPHER_CTX ctx; | |
540 | FILE *out; | |
541 | ||
542 | ctx = EVP_CIPHER_CTX_new(); | |
543 | EVP_EncryptInit_ex(ctx, EVP_idea_cbc(), NULL, key, iv); | |
544 | ||
545 | if(!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) | |
546 | { | |
547 | /* Error */ | |
548 | return 0; | |
549 | } | |
550 | /* Buffer passed to EVP_EncryptFinal() must be after data just | |
551 | * encrypted to avoid overwriting it. | |
552 | */ | |
553 | if(!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) | |
554 | { | |
555 | /* Error */ | |
556 | return 0; | |
557 | } | |
558 | outlen += tmplen; | |
559 | EVP_CIPHER_CTX_free(ctx); | |
560 | /* Need binary mode for fopen because encrypted data is | |
561 | * binary data. Also cannot use strlen() on it because | |
18135561 | 562 | * it wont be null terminated and may contain embedded |
1bc74519 RS |
563 | * nulls. |
564 | */ | |
565 | out = fopen(outfile, "wb"); | |
566 | fwrite(outbuf, 1, outlen, out); | |
567 | fclose(out); | |
568 | return 1; | |
569 | } | |
18135561 DSH |
570 | |
571 | The ciphertext from the above example can be decrypted using the B<openssl> | |
fd4592be | 572 | utility with the command line (shown on two lines for clarity): |
c7497f34 | 573 | |
fd4592be JS |
574 | openssl idea -d <filename |
575 | -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 | |
18135561 | 576 | |
fd4592be JS |
577 | General encryption and decryption function example using FILE I/O and AES128 |
578 | with a 128-bit key: | |
18135561 DSH |
579 | |
580 | int do_crypt(FILE *in, FILE *out, int do_encrypt) | |
1bc74519 RS |
581 | { |
582 | /* Allow enough space in output buffer for additional block */ | |
583 | unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH]; | |
584 | int inlen, outlen; | |
585 | EVP_CIPHER_CTX *ctx; | |
586 | /* Bogus key and IV: we'd normally set these from | |
587 | * another source. | |
588 | */ | |
589 | unsigned char key[] = "0123456789abcdeF"; | |
590 | unsigned char iv[] = "1234567887654321"; | |
591 | ||
592 | /* Don't set key or IV right away; we want to check lengths */ | |
593 | ctx = EVP_CIPHER_CTX_new(); | |
594 | EVP_CipherInit_ex(&ctx, EVP_aes_128_cbc(), NULL, NULL, NULL, | |
595 | do_encrypt); | |
596 | OPENSSL_assert(EVP_CIPHER_CTX_key_length(ctx) == 16); | |
597 | OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) == 16); | |
598 | ||
599 | /* Now we can set key and IV */ | |
600 | EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, do_encrypt); | |
601 | ||
602 | for(;;) | |
603 | { | |
604 | inlen = fread(inbuf, 1, 1024, in); | |
605 | if(inlen <= 0) break; | |
606 | if(!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) | |
607 | { | |
608 | /* Error */ | |
609 | EVP_CIPHER_CTX_free(ctx); | |
610 | return 0; | |
611 | } | |
612 | fwrite(outbuf, 1, outlen, out); | |
613 | } | |
614 | if(!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) | |
615 | { | |
616 | /* Error */ | |
617 | EVP_CIPHER_CTX_free(ctx); | |
618 | return 0; | |
619 | } | |
620 | fwrite(outbuf, 1, outlen, out); | |
621 | ||
622 | EVP_CIPHER_CTX_free(ctx); | |
623 | return 1; | |
624 | } | |
18135561 DSH |
625 | |
626 | ||
72b60351 DSH |
627 | =head1 SEE ALSO |
628 | ||
9b86974e | 629 | L<evp(3)> |
72b60351 DSH |
630 | |
631 | =head1 HISTORY | |
632 | ||
e4bbee96 | 633 | Support for OCB mode was added in OpenSSL 1.1.0 |
a528d4f0 | 634 | |
05fdb8d3 RL |
635 | B<EVP_CIPHER_CTX> was made opaque in OpenSSL 1.1.0. As a result, |
636 | EVP_CIPHER_CTX_reset() appeared and EVP_CIPHER_CTX_cleanup() | |
637 | disappeared. EVP_CIPHER_CTX_init() remains as an alias for | |
638 | EVP_CIPHER_CTX_reset(). | |
639 | ||
e2f92610 RS |
640 | =head1 COPYRIGHT |
641 | ||
642 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
643 | ||
644 | Licensed under the OpenSSL license (the "License"). You may not use | |
645 | this file except in compliance with the License. You can obtain a copy | |
646 | in the file LICENSE in the source distribution or at | |
647 | L<https://www.openssl.org/source/license.html>. | |
648 | ||
649 | =cut |