Import OpenSSL-1.0.1h.
[dragonfly.git] / crypto / openssl / doc / apps / enc.pod
CommitLineData
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1=pod
2
3=head1 NAME
4
5enc - symmetric cipher routines
6
7=head1 SYNOPSIS
8
9B<openssl enc -ciphername>
10[B<-in filename>]
11[B<-out filename>]
12[B<-pass arg>]
13[B<-e>]
14[B<-d>]
919b01cc 15[B<-a/-base64>]
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16[B<-A>]
17[B<-k password>]
18[B<-kfile filename>]
19[B<-K key>]
20[B<-iv IV>]
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21[B<-S salt>]
22[B<-salt>]
23[B<-nosalt>]
24[B<-z>]
25[B<-md>]
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26[B<-p>]
27[B<-P>]
28[B<-bufsize number>]
29[B<-nopad>]
30[B<-debug>]
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31[B<-none>]
32[B<-engine id>]
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33
34=head1 DESCRIPTION
35
36The symmetric cipher commands allow data to be encrypted or decrypted
37using various block and stream ciphers using keys based on passwords
38or explicitly provided. Base64 encoding or decoding can also be performed
39either by itself or in addition to the encryption or decryption.
40
41=head1 OPTIONS
42
43=over 4
44
45=item B<-in filename>
46
47the input filename, standard input by default.
48
49=item B<-out filename>
50
51the output filename, standard output by default.
52
53=item B<-pass arg>
54
55the password source. For more information about the format of B<arg>
56see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
57
58=item B<-salt>
59
5f042374 60use a salt in the key derivation routines. This is the default.
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61
62=item B<-nosalt>
63
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64don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
65used except for test purposes or compatibility with ancient versions of OpenSSL
66and SSLeay.
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67
68=item B<-e>
69
70encrypt the input data: this is the default.
71
72=item B<-d>
73
74decrypt the input data.
75
76=item B<-a>
77
78base64 process the data. This means that if encryption is taking place
79the data is base64 encoded after encryption. If decryption is set then
80the input data is base64 decoded before being decrypted.
81
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82=item B<-base64>
83
84same as B<-a>
85
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86=item B<-A>
87
88if the B<-a> option is set then base64 process the data on one line.
89
90=item B<-k password>
91
92the password to derive the key from. This is for compatibility with previous
93versions of OpenSSL. Superseded by the B<-pass> argument.
94
95=item B<-kfile filename>
96
97read the password to derive the key from the first line of B<filename>.
98This is for compatibility with previous versions of OpenSSL. Superseded by
99the B<-pass> argument.
100
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101=item B<-nosalt>
102
103do not use a salt
104
105=item B<-salt>
106
107use salt (randomly generated or provide with B<-S> option) when
108encrypting (this is the default).
109
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110=item B<-S salt>
111
919b01cc 112the actual salt to use: this must be represented as a string of hex digits.
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113
114=item B<-K key>
115
116the actual key to use: this must be represented as a string comprised only
117of hex digits. If only the key is specified, the IV must additionally specified
118using the B<-iv> option. When both a key and a password are specified, the
119key given with the B<-K> option will be used and the IV generated from the
120password will be taken. It probably does not make much sense to specify
121both key and password.
122
123=item B<-iv IV>
124
125the actual IV to use: this must be represented as a string comprised only
126of hex digits. When only the key is specified using the B<-K> option, the
127IV must explicitly be defined. When a password is being specified using
128one of the other options, the IV is generated from this password.
129
130=item B<-p>
131
132print out the key and IV used.
133
134=item B<-P>
135
136print out the key and IV used then immediately exit: don't do any encryption
137or decryption.
138
139=item B<-bufsize number>
140
141set the buffer size for I/O
142
143=item B<-nopad>
144
145disable standard block padding
146
147=item B<-debug>
148
149debug the BIOs used for I/O.
150
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151=item B<-z>
152
153Compress or decompress clear text using zlib before encryption or after
154decryption. This option exists only if OpenSSL with compiled with zlib
155or zlib-dynamic option.
156
157=item B<-none>
158
159Use NULL cipher (no encryption or decryption of input).
160
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161=back
162
163=head1 NOTES
164
165The program can be called either as B<openssl ciphername> or
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166B<openssl enc -ciphername>. But the first form doesn't work with
167engine-provided ciphers, because this form is processed before the
168configuration file is read and any ENGINEs loaded.
169
170Engines which provide entirely new encryption algorithms (such as ccgost
171engine which provides gost89 algorithm) should be configured in the
172configuration file. Engines, specified in the command line using -engine
173options can only be used for hadrware-assisted implementations of
174ciphers, which are supported by OpenSSL core or other engine, specified
175in the configuration file.
176
177When enc command lists supported ciphers, ciphers provided by engines,
178specified in the configuration files are listed too.
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179
180A password will be prompted for to derive the key and IV if necessary.
181
182The B<-salt> option should B<ALWAYS> be used if the key is being derived
183from a password unless you want compatibility with previous versions of
184OpenSSL and SSLeay.
185
186Without the B<-salt> option it is possible to perform efficient dictionary
187attacks on the password and to attack stream cipher encrypted data. The reason
188for this is that without the salt the same password always generates the same
189encryption key. When the salt is being used the first eight bytes of the
190encrypted data are reserved for the salt: it is generated at random when
191encrypting a file and read from the encrypted file when it is decrypted.
192
193Some of the ciphers do not have large keys and others have security
194implications if not used correctly. A beginner is advised to just use
195a strong block cipher in CBC mode such as bf or des3.
196
197All the block ciphers normally use PKCS#5 padding also known as standard block
198padding: this allows a rudimentary integrity or password check to be
199performed. However since the chance of random data passing the test is
200better than 1 in 256 it isn't a very good test.
201
202If padding is disabled then the input data must be a multiple of the cipher
203block length.
204
205All RC2 ciphers have the same key and effective key length.
206
207Blowfish and RC5 algorithms use a 128 bit key.
208
209=head1 SUPPORTED CIPHERS
210
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211Note that some of these ciphers can be disabled at compile time
212and some are available only if an appropriate engine is configured
213in the configuration file. The output of the B<enc> command run with
214unsupported options (for example B<openssl enc -help>) includes a
215list of ciphers, supported by your versesion of OpenSSL, including
216ones provided by configured engines.
217
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218The B<enc> program does not support authenticated encryption modes
219like CCM and GCM. The utility does not store or retrieve the
220authentication tag.
221
919b01cc 222
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223 base64 Base 64
224
225 bf-cbc Blowfish in CBC mode
226 bf Alias for bf-cbc
227 bf-cfb Blowfish in CFB mode
228 bf-ecb Blowfish in ECB mode
229 bf-ofb Blowfish in OFB mode
230
231 cast-cbc CAST in CBC mode
232 cast Alias for cast-cbc
233 cast5-cbc CAST5 in CBC mode
234 cast5-cfb CAST5 in CFB mode
235 cast5-ecb CAST5 in ECB mode
236 cast5-ofb CAST5 in OFB mode
237
238 des-cbc DES in CBC mode
239 des Alias for des-cbc
240 des-cfb DES in CBC mode
241 des-ofb DES in OFB mode
242 des-ecb DES in ECB mode
243
244 des-ede-cbc Two key triple DES EDE in CBC mode
245 des-ede Two key triple DES EDE in ECB mode
246 des-ede-cfb Two key triple DES EDE in CFB mode
247 des-ede-ofb Two key triple DES EDE in OFB mode
248
249 des-ede3-cbc Three key triple DES EDE in CBC mode
250 des-ede3 Three key triple DES EDE in ECB mode
251 des3 Alias for des-ede3-cbc
252 des-ede3-cfb Three key triple DES EDE CFB mode
253 des-ede3-ofb Three key triple DES EDE in OFB mode
254
255 desx DESX algorithm.
256
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257 gost89 GOST 28147-89 in CFB mode (provided by ccgost engine)
258 gost89-cnt `GOST 28147-89 in CNT mode (provided by ccgost engine)
259
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260 idea-cbc IDEA algorithm in CBC mode
261 idea same as idea-cbc
262 idea-cfb IDEA in CFB mode
263 idea-ecb IDEA in ECB mode
264 idea-ofb IDEA in OFB mode
265
266 rc2-cbc 128 bit RC2 in CBC mode
267 rc2 Alias for rc2-cbc
268 rc2-cfb 128 bit RC2 in CFB mode
269 rc2-ecb 128 bit RC2 in ECB mode
270 rc2-ofb 128 bit RC2 in OFB mode
271 rc2-64-cbc 64 bit RC2 in CBC mode
272 rc2-40-cbc 40 bit RC2 in CBC mode
273
274 rc4 128 bit RC4
275 rc4-64 64 bit RC4
276 rc4-40 40 bit RC4
277
278 rc5-cbc RC5 cipher in CBC mode
279 rc5 Alias for rc5-cbc
280 rc5-cfb RC5 cipher in CFB mode
281 rc5-ecb RC5 cipher in ECB mode
282 rc5-ofb RC5 cipher in OFB mode
283
284 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
285 aes-[128|192|256] Alias for aes-[128|192|256]-cbc
286 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
287 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
288 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
289 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
290 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
291
292=head1 EXAMPLES
293
294Just base64 encode a binary file:
295
296 openssl base64 -in file.bin -out file.b64
297
298Decode the same file
299
300 openssl base64 -d -in file.b64 -out file.bin
301
302Encrypt a file using triple DES in CBC mode using a prompted password:
303
304 openssl des3 -salt -in file.txt -out file.des3
305
306Decrypt a file using a supplied password:
307
308 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
309
310Encrypt a file then base64 encode it (so it can be sent via mail for example)
311using Blowfish in CBC mode:
312
313 openssl bf -a -salt -in file.txt -out file.bf
314
315Base64 decode a file then decrypt it:
316
317 openssl bf -d -salt -a -in file.bf -out file.txt
318
319Decrypt some data using a supplied 40 bit RC4 key:
320
321 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
322
323=head1 BUGS
324
325The B<-A> option when used with large files doesn't work properly.
326
327There should be an option to allow an iteration count to be included.
328
329The B<enc> program only supports a fixed number of algorithms with
330certain parameters. So if, for example, you want to use RC2 with a
33176 bit key or RC4 with an 84 bit key you can't use this program.
332
333=cut