Import OpenSSL-1.0.1g.
[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
218
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219 base64 Base 64
220
221 bf-cbc Blowfish in CBC mode
222 bf Alias for bf-cbc
223 bf-cfb Blowfish in CFB mode
224 bf-ecb Blowfish in ECB mode
225 bf-ofb Blowfish in OFB mode
226
227 cast-cbc CAST in CBC mode
228 cast Alias for cast-cbc
229 cast5-cbc CAST5 in CBC mode
230 cast5-cfb CAST5 in CFB mode
231 cast5-ecb CAST5 in ECB mode
232 cast5-ofb CAST5 in OFB mode
233
234 des-cbc DES in CBC mode
235 des Alias for des-cbc
236 des-cfb DES in CBC mode
237 des-ofb DES in OFB mode
238 des-ecb DES in ECB mode
239
240 des-ede-cbc Two key triple DES EDE in CBC mode
241 des-ede Two key triple DES EDE in ECB mode
242 des-ede-cfb Two key triple DES EDE in CFB mode
243 des-ede-ofb Two key triple DES EDE in OFB mode
244
245 des-ede3-cbc Three key triple DES EDE in CBC mode
246 des-ede3 Three key triple DES EDE in ECB mode
247 des3 Alias for des-ede3-cbc
248 des-ede3-cfb Three key triple DES EDE CFB mode
249 des-ede3-ofb Three key triple DES EDE in OFB mode
250
251 desx DESX algorithm.
252
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253 gost89 GOST 28147-89 in CFB mode (provided by ccgost engine)
254 gost89-cnt `GOST 28147-89 in CNT mode (provided by ccgost engine)
255
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256 idea-cbc IDEA algorithm in CBC mode
257 idea same as idea-cbc
258 idea-cfb IDEA in CFB mode
259 idea-ecb IDEA in ECB mode
260 idea-ofb IDEA in OFB mode
261
262 rc2-cbc 128 bit RC2 in CBC mode
263 rc2 Alias for rc2-cbc
264 rc2-cfb 128 bit RC2 in CFB mode
265 rc2-ecb 128 bit RC2 in ECB mode
266 rc2-ofb 128 bit RC2 in OFB mode
267 rc2-64-cbc 64 bit RC2 in CBC mode
268 rc2-40-cbc 40 bit RC2 in CBC mode
269
270 rc4 128 bit RC4
271 rc4-64 64 bit RC4
272 rc4-40 40 bit RC4
273
274 rc5-cbc RC5 cipher in CBC mode
275 rc5 Alias for rc5-cbc
276 rc5-cfb RC5 cipher in CFB mode
277 rc5-ecb RC5 cipher in ECB mode
278 rc5-ofb RC5 cipher in OFB mode
279
280 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
281 aes-[128|192|256] Alias for aes-[128|192|256]-cbc
282 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
283 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
284 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
285 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
286 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
287
288=head1 EXAMPLES
289
290Just base64 encode a binary file:
291
292 openssl base64 -in file.bin -out file.b64
293
294Decode the same file
295
296 openssl base64 -d -in file.b64 -out file.bin
297
298Encrypt a file using triple DES in CBC mode using a prompted password:
299
300 openssl des3 -salt -in file.txt -out file.des3
301
302Decrypt a file using a supplied password:
303
304 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
305
306Encrypt a file then base64 encode it (so it can be sent via mail for example)
307using Blowfish in CBC mode:
308
309 openssl bf -a -salt -in file.txt -out file.bf
310
311Base64 decode a file then decrypt it:
312
313 openssl bf -d -salt -a -in file.bf -out file.txt
314
315Decrypt some data using a supplied 40 bit RC4 key:
316
317 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
318
319=head1 BUGS
320
321The B<-A> option when used with large files doesn't work properly.
322
323There should be an option to allow an iteration count to be included.
324
325The B<enc> program only supports a fixed number of algorithms with
326certain parameters. So if, for example, you want to use RC2 with a
32776 bit key or RC4 with an 84 bit key you can't use this program.
328
329=cut