5 enc - symmetric cipher routines
9 B<openssl enc -I<cipher>>
39 B<openssl> I<[cipher]> [B<...>]
43 The symmetric cipher commands allow data to be encrypted or decrypted
44 using various block and stream ciphers using keys based on passwords
45 or explicitly provided. Base64 encoding or decoding can also be performed
46 either by itself or in addition to the encryption or decryption.
54 Print out a usage message.
58 List all supported ciphers.
62 The input filename, standard input by default.
64 =item B<-out filename>
66 The output filename, standard output by default.
70 The password source. For more information about the format of B<arg>
71 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
75 Encrypt the input data: this is the default.
79 Decrypt the input data.
83 Base64 process the data. This means that if encryption is taking place
84 the data is base64 encoded after encryption. If decryption is set then
85 the input data is base64 decoded before being decrypted.
93 If the B<-a> option is set then base64 process the data on one line.
97 The password to derive the key from. This is for compatibility with previous
98 versions of OpenSSL. Superseded by the B<-pass> argument.
100 =item B<-kfile filename>
102 Read the password to derive the key from the first line of B<filename>.
103 This is for compatibility with previous versions of OpenSSL. Superseded by
104 the B<-pass> argument.
108 Use the specified digest to create the key from the passphrase.
109 The default algorithm is sha-256.
113 Don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
114 used except for test purposes or compatibility with ancient versions of
119 Use salt (randomly generated or provide with B<-S> option) when
120 encrypting, this is the default.
124 The actual salt to use: this must be represented as a string of hex digits.
128 The actual key to use: this must be represented as a string comprised only
129 of hex digits. If only the key is specified, the IV must additionally specified
130 using the B<-iv> option. When both a key and a password are specified, the
131 key given with the B<-K> option will be used and the IV generated from the
132 password will be taken. It does not make much sense to specify both key
137 The actual IV to use: this must be represented as a string comprised only
138 of hex digits. When only the key is specified using the B<-K> option, the
139 IV must explicitly be defined. When a password is being specified using
140 one of the other options, the IV is generated from this password.
144 Print out the key and IV used.
148 Print out the key and IV used then immediately exit: don't do any encryption
151 =item B<-bufsize number>
153 Set the buffer size for I/O.
157 Disable standard block padding.
161 Debug the BIOs used for I/O.
165 Compress or decompress clear text using zlib before encryption or after
166 decryption. This option exists only if OpenSSL with compiled with zlib
167 or zlib-dynamic option.
171 Use NULL cipher (no encryption or decryption of input).
173 =item B<-rand file...>
175 A file or files containing random data used to seed the random number
177 Multiple files can be specified separated by an OS-dependent character.
178 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
181 =item [B<-writerand file>]
183 Writes random data to the specified I<file> upon exit.
184 This can be used with a subsequent B<-rand> flag.
190 The program can be called either as B<openssl cipher> or
191 B<openssl enc -cipher>. The first form doesn't work with
192 engine-provided ciphers, because this form is processed before the
193 configuration file is read and any ENGINEs loaded.
194 Use the B<list> command to get a list of supported ciphers.
196 Engines which provide entirely new encryption algorithms (such as the ccgost
197 engine which provides gost89 algorithm) should be configured in the
198 configuration file. Engines specified on the command line using -engine
199 options can only be used for hardware-assisted implementations of
200 ciphers which are supported by the OpenSSL core or another engine specified
201 in the configuration file.
203 When the enc command lists supported ciphers, ciphers provided by engines,
204 specified in the configuration files are listed too.
206 A password will be prompted for to derive the key and IV if necessary.
208 The B<-salt> option should B<ALWAYS> be used if the key is being derived
209 from a password unless you want compatibility with previous versions of
212 Without the B<-salt> option it is possible to perform efficient dictionary
213 attacks on the password and to attack stream cipher encrypted data. The reason
214 for this is that without the salt the same password always generates the same
215 encryption key. When the salt is being used the first eight bytes of the
216 encrypted data are reserved for the salt: it is generated at random when
217 encrypting a file and read from the encrypted file when it is decrypted.
219 Some of the ciphers do not have large keys and others have security
220 implications if not used correctly. A beginner is advised to just use
221 a strong block cipher, such as AES, in CBC mode.
223 All the block ciphers normally use PKCS#5 padding, also known as standard
224 block padding. This allows a rudimentary integrity or password check to
225 be performed. However since the chance of random data passing the test
226 is better than 1 in 256 it isn't a very good test.
228 If padding is disabled then the input data must be a multiple of the cipher
231 All RC2 ciphers have the same key and effective key length.
233 Blowfish and RC5 algorithms use a 128 bit key.
235 =head1 SUPPORTED CIPHERS
237 Note that some of these ciphers can be disabled at compile time
238 and some are available only if an appropriate engine is configured
239 in the configuration file. The output of the B<enc> command run with
240 the B<-ciphers> option (that is B<openssl enc -ciphers>) produces a
241 list of ciphers, supported by your version of OpenSSL, including
242 ones provided by configured engines.
244 The B<enc> program does not support authenticated encryption modes
245 like CCM and GCM. The utility does not store or retrieve the
251 bf-cbc Blowfish in CBC mode
253 bf-cfb Blowfish in CFB mode
254 bf-ecb Blowfish in ECB mode
255 bf-ofb Blowfish in OFB mode
257 cast-cbc CAST in CBC mode
258 cast Alias for cast-cbc
259 cast5-cbc CAST5 in CBC mode
260 cast5-cfb CAST5 in CFB mode
261 cast5-ecb CAST5 in ECB mode
262 cast5-ofb CAST5 in OFB mode
264 des-cbc DES in CBC mode
265 des Alias for des-cbc
266 des-cfb DES in CBC mode
267 des-ofb DES in OFB mode
268 des-ecb DES in ECB mode
270 des-ede-cbc Two key triple DES EDE in CBC mode
271 des-ede Two key triple DES EDE in ECB mode
272 des-ede-cfb Two key triple DES EDE in CFB mode
273 des-ede-ofb Two key triple DES EDE in OFB mode
275 des-ede3-cbc Three key triple DES EDE in CBC mode
276 des-ede3 Three key triple DES EDE in ECB mode
277 des3 Alias for des-ede3-cbc
278 des-ede3-cfb Three key triple DES EDE CFB mode
279 des-ede3-ofb Three key triple DES EDE in OFB mode
283 gost89 GOST 28147-89 in CFB mode (provided by ccgost engine)
284 gost89-cnt `GOST 28147-89 in CNT mode (provided by ccgost engine)
286 idea-cbc IDEA algorithm in CBC mode
287 idea same as idea-cbc
288 idea-cfb IDEA in CFB mode
289 idea-ecb IDEA in ECB mode
290 idea-ofb IDEA in OFB mode
292 rc2-cbc 128 bit RC2 in CBC mode
293 rc2 Alias for rc2-cbc
294 rc2-cfb 128 bit RC2 in CFB mode
295 rc2-ecb 128 bit RC2 in ECB mode
296 rc2-ofb 128 bit RC2 in OFB mode
297 rc2-64-cbc 64 bit RC2 in CBC mode
298 rc2-40-cbc 40 bit RC2 in CBC mode
304 rc5-cbc RC5 cipher in CBC mode
305 rc5 Alias for rc5-cbc
306 rc5-cfb RC5 cipher in CFB mode
307 rc5-ecb RC5 cipher in ECB mode
308 rc5-ofb RC5 cipher in OFB mode
310 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
311 aes[128|192|256] Alias for aes-[128|192|256]-cbc
312 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
313 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
314 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
315 aes-[128|192|256]-ctr 128/192/256 bit AES in CTR mode
316 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
317 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
319 camellia-[128|192|256]-cbc 128/192/256 bit Camellia in CBC mode
320 camellia[128|192|256] Alias for camellia-[128|192|256]-cbc
321 camellia-[128|192|256]-cfb 128/192/256 bit Camellia in 128 bit CFB mode
322 camellia-[128|192|256]-cfb1 128/192/256 bit Camellia in 1 bit CFB mode
323 camellia-[128|192|256]-cfb8 128/192/256 bit Camellia in 8 bit CFB mode
324 camellia-[128|192|256]-ctr 128/192/256 bit Camellia in CTR mode
325 camellia-[128|192|256]-ecb 128/192/256 bit Camellia in ECB mode
326 camellia-[128|192|256]-ofb 128/192/256 bit Camellia in OFB mode
330 Just base64 encode a binary file:
332 openssl base64 -in file.bin -out file.b64
336 openssl base64 -d -in file.b64 -out file.bin
338 Encrypt a file using triple DES in CBC mode using a prompted password:
340 openssl des3 -salt -in file.txt -out file.des3
342 Decrypt a file using a supplied password:
344 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
346 Encrypt a file then base64 encode it (so it can be sent via mail for example)
347 using Blowfish in CBC mode:
349 openssl bf -a -salt -in file.txt -out file.bf
351 Base64 decode a file then decrypt it:
353 openssl bf -d -salt -a -in file.bf -out file.txt
355 Decrypt some data using a supplied 40 bit RC4 key:
357 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
361 The B<-A> option when used with large files doesn't work properly.
363 There should be an option to allow an iteration count to be included.
365 The B<enc> program only supports a fixed number of algorithms with
366 certain parameters. So if, for example, you want to use RC2 with a
367 76 bit key or RC4 with an 84 bit key you can't use this program.
371 The default digest was changed from MD5 to SHA256 in Openssl 1.1.0.
375 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
377 Licensed under the OpenSSL license (the "License"). You may not use
378 this file except in compliance with the License. You can obtain a copy
379 in the file LICENSE in the source distribution or at
380 L<https://www.openssl.org/source/license.html>.