5 enc - symmetric cipher routines
9 B<openssl enc -ciphername>
38 The symmetric cipher commands allow data to be encrypted or decrypted
39 using various block and stream ciphers using keys based on passwords
40 or explicitly provided. Base64 encoding or decoding can also be performed
41 either by itself or in addition to the encryption or decryption.
49 Print out a usage message.
53 List all supported ciphers.
57 the input filename, standard input by default.
59 =item B<-out filename>
61 the output filename, standard output by default.
65 the password source. For more information about the format of B<arg>
66 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
70 encrypt the input data: this is the default.
74 decrypt the input data.
78 base64 process the data. This means that if encryption is taking place
79 the data is base64 encoded after encryption. If decryption is set then
80 the input data is base64 decoded before being decrypted.
88 if the B<-a> option is set then base64 process the data on one line.
92 the password to derive the key from. This is for compatibility with previous
93 versions of OpenSSL. Superseded by the B<-pass> argument.
95 =item B<-kfile filename>
97 read the password to derive the key from the first line of B<filename>.
98 This is for compatibility with previous versions of OpenSSL. Superseded by
99 the B<-pass> argument.
103 Use the specified digest to create the key from the passphrase.
104 The default algorithm is sha-256.
108 don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
109 used except for test purposes or compatibility with ancient versions of
114 use salt (randomly generated or provide with B<-S> option) when
115 encrypting (this is the default).
119 the actual salt to use: this must be represented as a string of hex digits.
123 the actual key to use: this must be represented as a string comprised only
124 of hex digits. If only the key is specified, the IV must additionally specified
125 using the B<-iv> option. When both a key and a password are specified, the
126 key given with the B<-K> option will be used and the IV generated from the
127 password will be taken. It probably does not make much sense to specify
128 both key and password.
132 the actual IV to use: this must be represented as a string comprised only
133 of hex digits. When only the key is specified using the B<-K> option, the
134 IV must explicitly be defined. When a password is being specified using
135 one of the other options, the IV is generated from this password.
139 print out the key and IV used.
143 print out the key and IV used then immediately exit: don't do any encryption
146 =item B<-bufsize number>
148 set the buffer size for I/O
152 disable standard block padding
156 debug the BIOs used for I/O.
160 Compress or decompress clear text using zlib before encryption or after
161 decryption. This option exists only if OpenSSL with compiled with zlib
162 or zlib-dynamic option.
166 Use NULL cipher (no encryption or decryption of input).
172 The program can be called either as B<openssl ciphername> or
173 B<openssl enc -ciphername>. But the first form doesn't work with
174 engine-provided ciphers, because this form is processed before the
175 configuration file is read and any ENGINEs loaded.
177 Engines which provide entirely new encryption algorithms (such as ccgost
178 engine which provides gost89 algorithm) should be configured in the
179 configuration file. Engines, specified in the command line using -engine
180 options can only be used for hardware-assisted implementations of
181 ciphers, which are supported by OpenSSL core or other engine, specified
182 in the configuration file.
184 When enc command lists supported ciphers, ciphers provided by engines,
185 specified in the configuration files are listed too.
187 A password will be prompted for to derive the key and IV if necessary.
189 The B<-salt> option should B<ALWAYS> be used if the key is being derived
190 from a password unless you want compatibility with previous versions of
193 Without the B<-salt> option it is possible to perform efficient dictionary
194 attacks on the password and to attack stream cipher encrypted data. The reason
195 for this is that without the salt the same password always generates the same
196 encryption key. When the salt is being used the first eight bytes of the
197 encrypted data are reserved for the salt: it is generated at random when
198 encrypting a file and read from the encrypted file when it is decrypted.
200 Some of the ciphers do not have large keys and others have security
201 implications if not used correctly. A beginner is advised to just use
202 a strong block cipher in CBC mode such as bf or des3.
204 All the block ciphers normally use PKCS#5 padding also known as standard block
205 padding: this allows a rudimentary integrity or password check to be
206 performed. However since the chance of random data passing the test is
207 better than 1 in 256 it isn't a very good test.
209 If padding is disabled then the input data must be a multiple of the cipher
212 All RC2 ciphers have the same key and effective key length.
214 Blowfish and RC5 algorithms use a 128 bit key.
216 =head1 SUPPORTED CIPHERS
218 Note that some of these ciphers can be disabled at compile time
219 and some are available only if an appropriate engine is configured
220 in the configuration file. The output of the B<enc> command run with
221 unsupported options (for example B<openssl enc -help>) includes a
222 list of ciphers, supported by your version of OpenSSL, including
223 ones provided by configured engines.
225 The B<enc> program does not support authenticated encryption modes
226 like CCM and GCM. The utility does not store or retrieve the
232 bf-cbc Blowfish in CBC mode
234 bf-cfb Blowfish in CFB mode
235 bf-ecb Blowfish in ECB mode
236 bf-ofb Blowfish in OFB mode
238 cast-cbc CAST in CBC mode
239 cast Alias for cast-cbc
240 cast5-cbc CAST5 in CBC mode
241 cast5-cfb CAST5 in CFB mode
242 cast5-ecb CAST5 in ECB mode
243 cast5-ofb CAST5 in OFB mode
245 des-cbc DES in CBC mode
246 des Alias for des-cbc
247 des-cfb DES in CBC mode
248 des-ofb DES in OFB mode
249 des-ecb DES in ECB mode
251 des-ede-cbc Two key triple DES EDE in CBC mode
252 des-ede Two key triple DES EDE in ECB mode
253 des-ede-cfb Two key triple DES EDE in CFB mode
254 des-ede-ofb Two key triple DES EDE in OFB mode
256 des-ede3-cbc Three key triple DES EDE in CBC mode
257 des-ede3 Three key triple DES EDE in ECB mode
258 des3 Alias for des-ede3-cbc
259 des-ede3-cfb Three key triple DES EDE CFB mode
260 des-ede3-ofb Three key triple DES EDE in OFB mode
264 gost89 GOST 28147-89 in CFB mode (provided by ccgost engine)
265 gost89-cnt `GOST 28147-89 in CNT mode (provided by ccgost engine)
267 idea-cbc IDEA algorithm in CBC mode
268 idea same as idea-cbc
269 idea-cfb IDEA in CFB mode
270 idea-ecb IDEA in ECB mode
271 idea-ofb IDEA in OFB mode
273 rc2-cbc 128 bit RC2 in CBC mode
274 rc2 Alias for rc2-cbc
275 rc2-cfb 128 bit RC2 in CFB mode
276 rc2-ecb 128 bit RC2 in ECB mode
277 rc2-ofb 128 bit RC2 in OFB mode
278 rc2-64-cbc 64 bit RC2 in CBC mode
279 rc2-40-cbc 40 bit RC2 in CBC mode
285 rc5-cbc RC5 cipher in CBC mode
286 rc5 Alias for rc5-cbc
287 rc5-cfb RC5 cipher in CFB mode
288 rc5-ecb RC5 cipher in ECB mode
289 rc5-ofb RC5 cipher in OFB mode
291 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
292 aes[128|192|256] Alias for aes-[128|192|256]-cbc
293 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
294 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
295 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
296 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
297 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
301 Just base64 encode a binary file:
303 openssl base64 -in file.bin -out file.b64
307 openssl base64 -d -in file.b64 -out file.bin
309 Encrypt a file using triple DES in CBC mode using a prompted password:
311 openssl des3 -salt -in file.txt -out file.des3
313 Decrypt a file using a supplied password:
315 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
317 Encrypt a file then base64 encode it (so it can be sent via mail for example)
318 using Blowfish in CBC mode:
320 openssl bf -a -salt -in file.txt -out file.bf
322 Base64 decode a file then decrypt it:
324 openssl bf -d -salt -a -in file.bf -out file.txt
326 Decrypt some data using a supplied 40 bit RC4 key:
328 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
332 The B<-A> option when used with large files doesn't work properly.
334 There should be an option to allow an iteration count to be included.
336 The B<enc> program only supports a fixed number of algorithms with
337 certain parameters. So if, for example, you want to use RC2 with a
338 76 bit key or RC4 with an 84 bit key you can't use this program.
342 The default digest was changed from MD5 to SHA256 in Openssl 1.1.
346 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
348 Licensed under the OpenSSL license (the "License"). You may not use
349 this file except in compliance with the License. You can obtain a copy
350 in the file LICENSE in the source distribution or at
351 L<https://www.openssl.org/source/license.html>.