5 enc - symmetric cipher routines
9 B<openssl enc -ciphername>
36 The symmetric cipher commands allow data to be encrypted or decrypted
37 using various block and stream ciphers using keys based on passwords
38 or explicitly provided. Base64 encoding or decoding can also be performed
39 either by itself or in addition to the encryption or decryption.
47 the input filename, standard input by default.
49 =item B<-out filename>
51 the output filename, standard output by default.
55 the password source. For more information about the format of B<arg>
56 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
60 use a salt in the key derivation routines. This option should B<ALWAYS>
61 be used unless compatibility with previous versions of OpenSSL or SSLeay
62 is required. This option is only present on OpenSSL versions 0.9.5 or
67 don't use a salt in the key derivation routines. This is the default for
68 compatibility with previous versions of OpenSSL and SSLeay.
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 Superseded by the B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 Superseded by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.
109 use salt (randomly generated or provide with B<-S> option) when
110 encrypting (this is the default).
114 the actual salt to use: this must be represented as a string of hex digits.
118 the actual key to use: this must be represented as a string comprised only
119 of hex digits. If only the key is specified, the IV must additionally specified
120 using the B<-iv> option. When both a key and a password are specified, the
121 key given with the B<-K> option will be used and the IV generated from the
122 password will be taken. It probably does not make much sense to specify
123 both key and password.
127 the actual IV to use: this must be represented as a string comprised only
128 of hex digits. When only the key is specified using the B<-K> option, the
129 IV must explicitly be defined. When a password is being specified using
130 one of the other options, the IV is generated from this password.
134 print out the key and IV used.
138 print out the key and IV used then immediately exit: don't do any encryption
141 =item B<-bufsize number>
143 set the buffer size for I/O
147 disable standard block padding
151 debug the BIOs used for I/O.
155 Compress or decompress clear text using zlib before encryption or after
156 decryption. This option exists only if OpenSSL with compiled with zlib
157 or zlib-dynamic option.
161 Use NULL cipher (no encryption or decryption of input).
167 The program can be called either as B<openssl ciphername> or
168 B<openssl enc -ciphername>. But the first form doesn't work with
169 engine-provided ciphers, because this form is processed before the
170 configuration file is read and any ENGINEs loaded.
172 Engines which provide entirely new encryption algorithms (such as ccgost
173 engine which provides gost89 algorithm) should be configured in the
174 configuration file. Engines, specified in the command line using -engine
175 options can only be used for hadrware-assisted implementations of
176 ciphers, which are supported by OpenSSL core or other engine, specified
177 in the configuration file.
179 When enc command lists supported ciphers, ciphers provided by engines,
180 specified in the configuration files are listed too.
182 A password will be prompted for to derive the key and IV if necessary.
184 The B<-salt> option should B<ALWAYS> be used if the key is being derived
185 from a password unless you want compatibility with previous versions of
188 Without the B<-salt> option it is possible to perform efficient dictionary
189 attacks on the password and to attack stream cipher encrypted data. The reason
190 for this is that without the salt the same password always generates the same
191 encryption key. When the salt is being used the first eight bytes of the
192 encrypted data are reserved for the salt: it is generated at random when
193 encrypting a file and read from the encrypted file when it is decrypted.
195 Some of the ciphers do not have large keys and others have security
196 implications if not used correctly. A beginner is advised to just use
197 a strong block cipher in CBC mode such as bf or des3.
199 All the block ciphers normally use PKCS#5 padding also known as standard block
200 padding: this allows a rudimentary integrity or password check to be
201 performed. However since the chance of random data passing the test is
202 better than 1 in 256 it isn't a very good test.
204 If padding is disabled then the input data must be a multiple of the cipher
207 All RC2 ciphers have the same key and effective key length.
209 Blowfish and RC5 algorithms use a 128 bit key.
211 =head1 SUPPORTED CIPHERS
213 Note that some of these ciphers can be disabled at compile time
214 and some are available only if an appropriate engine is configured
215 in the configuration file. The output of the B<enc> command run with
216 unsupported options (for example B<openssl enc -help>) includes a
217 list of ciphers, supported by your versesion of OpenSSL, including
218 ones provided by configured engines.
223 bf-cbc Blowfish in CBC mode
225 bf-cfb Blowfish in CFB mode
226 bf-ecb Blowfish in ECB mode
227 bf-ofb Blowfish in OFB mode
229 cast-cbc CAST in CBC mode
230 cast Alias for cast-cbc
231 cast5-cbc CAST5 in CBC mode
232 cast5-cfb CAST5 in CFB mode
233 cast5-ecb CAST5 in ECB mode
234 cast5-ofb CAST5 in OFB mode
236 des-cbc DES in CBC mode
237 des Alias for des-cbc
238 des-cfb DES in CBC mode
239 des-ofb DES in OFB mode
240 des-ecb DES in ECB mode
242 des-ede-cbc Two key triple DES EDE in CBC mode
243 des-ede Two key triple DES EDE in ECB mode
244 des-ede-cfb Two key triple DES EDE in CFB mode
245 des-ede-ofb Two key triple DES EDE in OFB mode
247 des-ede3-cbc Three key triple DES EDE in CBC mode
248 des-ede3 Three key triple DES EDE in ECB mode
249 des3 Alias for des-ede3-cbc
250 des-ede3-cfb Three key triple DES EDE CFB mode
251 des-ede3-ofb Three key triple DES EDE in OFB mode
255 gost89 GOST 28147-89 in CFB mode (provided by ccgost engine)
256 gost89-cnt `GOST 28147-89 in CNT mode (provided by ccgost engine)
258 idea-cbc IDEA algorithm in CBC mode
259 idea same as idea-cbc
260 idea-cfb IDEA in CFB mode
261 idea-ecb IDEA in ECB mode
262 idea-ofb IDEA in OFB mode
264 rc2-cbc 128 bit RC2 in CBC mode
265 rc2 Alias for rc2-cbc
266 rc2-cfb 128 bit RC2 in CFB mode
267 rc2-ecb 128 bit RC2 in ECB mode
268 rc2-ofb 128 bit RC2 in OFB mode
269 rc2-64-cbc 64 bit RC2 in CBC mode
270 rc2-40-cbc 40 bit RC2 in CBC mode
276 rc5-cbc RC5 cipher in CBC mode
277 rc5 Alias for rc5-cbc
278 rc5-cfb RC5 cipher in CFB mode
279 rc5-ecb RC5 cipher in ECB mode
280 rc5-ofb RC5 cipher in OFB mode
282 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
283 aes-[128|192|256] Alias for aes-[128|192|256]-cbc
284 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
285 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
286 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
287 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
288 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
292 Just base64 encode a binary file:
294 openssl base64 -in file.bin -out file.b64
298 openssl base64 -d -in file.b64 -out file.bin
300 Encrypt a file using triple DES in CBC mode using a prompted password:
302 openssl des3 -salt -in file.txt -out file.des3
304 Decrypt a file using a supplied password:
306 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
308 Encrypt a file then base64 encode it (so it can be sent via mail for example)
309 using Blowfish in CBC mode:
311 openssl bf -a -salt -in file.txt -out file.bf
313 Base64 decode a file then decrypt it:
315 openssl bf -d -salt -a -in file.bf -out file.txt
317 Decrypt some data using a supplied 40 bit RC4 key:
319 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
323 The B<-A> option when used with large files doesn't work properly.
325 There should be an option to allow an iteration count to be included.
327 The B<enc> program only supports a fixed number of algorithms with
328 certain parameters. So if, for example, you want to use RC2 with a
329 76 bit key or RC4 with an 84 bit key you can't use this program.