5 enc - symmetric cipher routines
9 B<openssl enc -ciphername>
40 The symmetric cipher commands allow data to be encrypted or decrypted
41 using various block and stream ciphers using keys based on passwords
42 or explicitly provided. Base64 encoding or decoding can also be performed
43 either by itself or in addition to the encryption or decryption.
51 Print out a usage message.
55 List all supported ciphers.
59 The input filename, standard input by default.
61 =item B<-out filename>
63 The output filename, standard output by default.
67 The password source. For more information about the format of B<arg>
68 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
72 Encrypt the input data: this is the default.
76 Decrypt the input data.
80 Base64 process the data. This means that if encryption is taking place
81 the data is base64 encoded after encryption. If decryption is set then
82 the input data is base64 decoded before being decrypted.
90 If the B<-a> option is set then base64 process the data on one line.
94 The password to derive the key from. This is for compatibility with previous
95 versions of OpenSSL. Superseded by the B<-pass> argument.
97 =item B<-kfile filename>
99 Read the password to derive the key from the first line of B<filename>.
100 This is for compatibility with previous versions of OpenSSL. Superseded by
101 the B<-pass> argument.
105 Use the specified digest to create the key from the passphrase.
106 The default algorithm is sha-256.
110 Don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
111 used except for test purposes or compatibility with ancient versions of
116 Use salt (randomly generated or provide with B<-S> option) when
117 encrypting, this is the default.
121 The actual salt to use: this must be represented as a string of hex digits.
125 The actual key to use: this must be represented as a string comprised only
126 of hex digits. If only the key is specified, the IV must additionally specified
127 using the B<-iv> option. When both a key and a password are specified, the
128 key given with the B<-K> option will be used and the IV generated from the
129 password will be taken. It does not make much sense to specify both key
134 The actual IV to use: this must be represented as a string comprised only
135 of hex digits. When only the key is specified using the B<-K> option, the
136 IV must explicitly be defined. When a password is being specified using
137 one of the other options, the IV is generated from this password.
141 Print out the key and IV used.
145 Print out the key and IV used then immediately exit: don't do any encryption
148 =item B<-bufsize number>
150 Set the buffer size for I/O.
154 Disable standard block padding.
158 Debug the BIOs used for I/O.
162 Compress or decompress clear text using zlib before encryption or after
163 decryption. This option exists only if OpenSSL with compiled with zlib
164 or zlib-dynamic option.
168 Use NULL cipher (no encryption or decryption of input).
170 =item B<-rand file...>
172 A file or files containing random data used to seed the random number
174 Multiple files can be specified separated by an OS-dependent character.
175 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
178 =item [B<-writerand file>]
180 Writes random data to the specified I<file> upon exit.
181 This can be used with a subsequent B<-rand> flag.
187 The program can be called either as B<openssl ciphername> or
188 B<openssl enc -ciphername>. The first form doesn't work with
189 engine-provided ciphers, because this form is processed before the
190 configuration file is read and any ENGINEs loaded.
192 Engines which provide entirely new encryption algorithms (such as the ccgost
193 engine which provides gost89 algorithm) should be configured in the
194 configuration file. Engines specified on the command line using -engine
195 options can only be used for hardware-assisted implementations of
196 ciphers which are supported by the OpenSSL core or another engine specified
197 in the configuration file.
199 When the enc command lists supported ciphers, ciphers provided by engines,
200 specified in the configuration files are listed too.
202 A password will be prompted for to derive the key and IV if necessary.
204 The B<-salt> option should B<ALWAYS> be used if the key is being derived
205 from a password unless you want compatibility with previous versions of
208 Without the B<-salt> option it is possible to perform efficient dictionary
209 attacks on the password and to attack stream cipher encrypted data. The reason
210 for this is that without the salt the same password always generates the same
211 encryption key. When the salt is being used the first eight bytes of the
212 encrypted data are reserved for the salt: it is generated at random when
213 encrypting a file and read from the encrypted file when it is decrypted.
215 Some of the ciphers do not have large keys and others have security
216 implications if not used correctly. A beginner is advised to just use
217 a strong block cipher, such as AES, in CBC mode.
219 All the block ciphers normally use PKCS#5 padding, also known as standard
220 block padding. This allows a rudimentary integrity or password check to
221 be performed. However since the chance of random data passing the test
222 is better than 1 in 256 it isn't a very good test.
224 If padding is disabled then the input data must be a multiple of the cipher
227 All RC2 ciphers have the same key and effective key length.
229 Blowfish and RC5 algorithms use a 128 bit key.
231 =head1 SUPPORTED CIPHERS
233 Note that some of these ciphers can be disabled at compile time
234 and some are available only if an appropriate engine is configured
235 in the configuration file. The output of the B<enc> command run with
236 the B<-ciphers> option (that is B<openssl enc -ciphers>) produces a
237 list of ciphers, supported by your version of OpenSSL, including
238 ones provided by configured engines.
240 The B<enc> program does not support authenticated encryption modes
241 like CCM and GCM. The utility does not store or retrieve the
247 bf-cbc Blowfish in CBC mode
249 bf-cfb Blowfish in CFB mode
250 bf-ecb Blowfish in ECB mode
251 bf-ofb Blowfish in OFB mode
253 cast-cbc CAST in CBC mode
254 cast Alias for cast-cbc
255 cast5-cbc CAST5 in CBC mode
256 cast5-cfb CAST5 in CFB mode
257 cast5-ecb CAST5 in ECB mode
258 cast5-ofb CAST5 in OFB mode
260 des-cbc DES in CBC mode
261 des Alias for des-cbc
262 des-cfb DES in CBC mode
263 des-ofb DES in OFB mode
264 des-ecb DES in ECB mode
266 des-ede-cbc Two key triple DES EDE in CBC mode
267 des-ede Two key triple DES EDE in ECB mode
268 des-ede-cfb Two key triple DES EDE in CFB mode
269 des-ede-ofb Two key triple DES EDE in OFB mode
271 des-ede3-cbc Three key triple DES EDE in CBC mode
272 des-ede3 Three key triple DES EDE in ECB mode
273 des3 Alias for des-ede3-cbc
274 des-ede3-cfb Three key triple DES EDE CFB mode
275 des-ede3-ofb Three key triple DES EDE in OFB mode
279 gost89 GOST 28147-89 in CFB mode (provided by ccgost engine)
280 gost89-cnt `GOST 28147-89 in CNT mode (provided by ccgost engine)
282 idea-cbc IDEA algorithm in CBC mode
283 idea same as idea-cbc
284 idea-cfb IDEA in CFB mode
285 idea-ecb IDEA in ECB mode
286 idea-ofb IDEA in OFB mode
288 rc2-cbc 128 bit RC2 in CBC mode
289 rc2 Alias for rc2-cbc
290 rc2-cfb 128 bit RC2 in CFB mode
291 rc2-ecb 128 bit RC2 in ECB mode
292 rc2-ofb 128 bit RC2 in OFB mode
293 rc2-64-cbc 64 bit RC2 in CBC mode
294 rc2-40-cbc 40 bit RC2 in CBC mode
300 rc5-cbc RC5 cipher in CBC mode
301 rc5 Alias for rc5-cbc
302 rc5-cfb RC5 cipher in CFB mode
303 rc5-ecb RC5 cipher in ECB mode
304 rc5-ofb RC5 cipher in OFB mode
306 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
307 aes[128|192|256] Alias for aes-[128|192|256]-cbc
308 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
309 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
310 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
311 aes-[128|192|256]-ctr 128/192/256 bit AES in CTR mode
312 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
313 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
315 camellia-[128|192|256]-cbc 128/192/256 bit Camellia in CBC mode
316 camellia[128|192|256] Alias for camellia-[128|192|256]-cbc
317 camellia-[128|192|256]-cfb 128/192/256 bit Camellia in 128 bit CFB mode
318 camellia-[128|192|256]-cfb1 128/192/256 bit Camellia in 1 bit CFB mode
319 camellia-[128|192|256]-cfb8 128/192/256 bit Camellia in 8 bit CFB mode
320 camellia-[128|192|256]-ctr 128/192/256 bit Camellia in CTR mode
321 camellia-[128|192|256]-ecb 128/192/256 bit Camellia in ECB mode
322 camellia-[128|192|256]-ofb 128/192/256 bit Camellia in OFB mode
326 Just base64 encode a binary file:
328 openssl base64 -in file.bin -out file.b64
332 openssl base64 -d -in file.b64 -out file.bin
334 Encrypt a file using triple DES in CBC mode using a prompted password:
336 openssl des3 -salt -in file.txt -out file.des3
338 Decrypt a file using a supplied password:
340 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
342 Encrypt a file then base64 encode it (so it can be sent via mail for example)
343 using Blowfish in CBC mode:
345 openssl bf -a -salt -in file.txt -out file.bf
347 Base64 decode a file then decrypt it:
349 openssl bf -d -salt -a -in file.bf -out file.txt
351 Decrypt some data using a supplied 40 bit RC4 key:
353 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
357 The B<-A> option when used with large files doesn't work properly.
359 There should be an option to allow an iteration count to be included.
361 The B<enc> program only supports a fixed number of algorithms with
362 certain parameters. So if, for example, you want to use RC2 with a
363 76 bit key or RC4 with an 84 bit key you can't use this program.
367 The default digest was changed from MD5 to SHA256 in Openssl 1.1.0.
371 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
373 Licensed under the OpenSSL license (the "License"). You may not use
374 this file except in compliance with the License. You can obtain a copy
375 in the file LICENSE in the source distribution or at
376 L<https://www.openssl.org/source/license.html>.