Import OpenSSL-0.9.8m.
[dragonfly.git] / crypto / openssl / doc / apps / enc.pod
CommitLineData
730b1645
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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>]
15[B<-a>]
16[B<-A>]
17[B<-k password>]
18[B<-kfile filename>]
19[B<-K key>]
20[B<-iv IV>]
21[B<-p>]
22[B<-P>]
23[B<-bufsize number>]
24[B<-nopad>]
25[B<-debug>]
26
27=head1 DESCRIPTION
28
29The symmetric cipher commands allow data to be encrypted or decrypted
30using various block and stream ciphers using keys based on passwords
31or explicitly provided. Base64 encoding or decoding can also be performed
32either by itself or in addition to the encryption or decryption.
33
34=head1 OPTIONS
35
36=over 4
37
38=item B<-in filename>
39
40the input filename, standard input by default.
41
42=item B<-out filename>
43
44the output filename, standard output by default.
45
46=item B<-pass arg>
47
48the password source. For more information about the format of B<arg>
49see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
50
51=item B<-salt>
52
5f042374 53use a salt in the key derivation routines. This is the default.
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54
55=item B<-nosalt>
56
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57don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
58used except for test purposes or compatibility with ancient versions of OpenSSL
59and SSLeay.
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60
61=item B<-e>
62
63encrypt the input data: this is the default.
64
65=item B<-d>
66
67decrypt the input data.
68
69=item B<-a>
70
71base64 process the data. This means that if encryption is taking place
72the data is base64 encoded after encryption. If decryption is set then
73the input data is base64 decoded before being decrypted.
74
75=item B<-A>
76
77if the B<-a> option is set then base64 process the data on one line.
78
79=item B<-k password>
80
81the password to derive the key from. This is for compatibility with previous
82versions of OpenSSL. Superseded by the B<-pass> argument.
83
84=item B<-kfile filename>
85
86read the password to derive the key from the first line of B<filename>.
87This is for compatibility with previous versions of OpenSSL. Superseded by
88the B<-pass> argument.
89
90=item B<-S salt>
91
92the actual salt to use: this must be represented as a string comprised only
93of hex digits.
94
95=item B<-K key>
96
97the actual key to use: this must be represented as a string comprised only
98of hex digits. If only the key is specified, the IV must additionally specified
99using the B<-iv> option. When both a key and a password are specified, the
100key given with the B<-K> option will be used and the IV generated from the
101password will be taken. It probably does not make much sense to specify
102both key and password.
103
104=item B<-iv IV>
105
106the actual IV to use: this must be represented as a string comprised only
107of hex digits. When only the key is specified using the B<-K> option, the
108IV must explicitly be defined. When a password is being specified using
109one of the other options, the IV is generated from this password.
110
111=item B<-p>
112
113print out the key and IV used.
114
115=item B<-P>
116
117print out the key and IV used then immediately exit: don't do any encryption
118or decryption.
119
120=item B<-bufsize number>
121
122set the buffer size for I/O
123
124=item B<-nopad>
125
126disable standard block padding
127
128=item B<-debug>
129
130debug the BIOs used for I/O.
131
132=back
133
134=head1 NOTES
135
136The program can be called either as B<openssl ciphername> or
137B<openssl enc -ciphername>.
138
139A password will be prompted for to derive the key and IV if necessary.
140
141The B<-salt> option should B<ALWAYS> be used if the key is being derived
142from a password unless you want compatibility with previous versions of
143OpenSSL and SSLeay.
144
145Without the B<-salt> option it is possible to perform efficient dictionary
146attacks on the password and to attack stream cipher encrypted data. The reason
147for this is that without the salt the same password always generates the same
148encryption key. When the salt is being used the first eight bytes of the
149encrypted data are reserved for the salt: it is generated at random when
150encrypting a file and read from the encrypted file when it is decrypted.
151
152Some of the ciphers do not have large keys and others have security
153implications if not used correctly. A beginner is advised to just use
154a strong block cipher in CBC mode such as bf or des3.
155
156All the block ciphers normally use PKCS#5 padding also known as standard block
157padding: this allows a rudimentary integrity or password check to be
158performed. However since the chance of random data passing the test is
159better than 1 in 256 it isn't a very good test.
160
161If padding is disabled then the input data must be a multiple of the cipher
162block length.
163
164All RC2 ciphers have the same key and effective key length.
165
166Blowfish and RC5 algorithms use a 128 bit key.
167
168=head1 SUPPORTED CIPHERS
169
170 base64 Base 64
171
172 bf-cbc Blowfish in CBC mode
173 bf Alias for bf-cbc
174 bf-cfb Blowfish in CFB mode
175 bf-ecb Blowfish in ECB mode
176 bf-ofb Blowfish in OFB mode
177
178 cast-cbc CAST in CBC mode
179 cast Alias for cast-cbc
180 cast5-cbc CAST5 in CBC mode
181 cast5-cfb CAST5 in CFB mode
182 cast5-ecb CAST5 in ECB mode
183 cast5-ofb CAST5 in OFB mode
184
185 des-cbc DES in CBC mode
186 des Alias for des-cbc
187 des-cfb DES in CBC mode
188 des-ofb DES in OFB mode
189 des-ecb DES in ECB mode
190
191 des-ede-cbc Two key triple DES EDE in CBC mode
192 des-ede Two key triple DES EDE in ECB mode
193 des-ede-cfb Two key triple DES EDE in CFB mode
194 des-ede-ofb Two key triple DES EDE in OFB mode
195
196 des-ede3-cbc Three key triple DES EDE in CBC mode
197 des-ede3 Three key triple DES EDE in ECB mode
198 des3 Alias for des-ede3-cbc
199 des-ede3-cfb Three key triple DES EDE CFB mode
200 des-ede3-ofb Three key triple DES EDE in OFB mode
201
202 desx DESX algorithm.
203
204 idea-cbc IDEA algorithm in CBC mode
205 idea same as idea-cbc
206 idea-cfb IDEA in CFB mode
207 idea-ecb IDEA in ECB mode
208 idea-ofb IDEA in OFB mode
209
210 rc2-cbc 128 bit RC2 in CBC mode
211 rc2 Alias for rc2-cbc
212 rc2-cfb 128 bit RC2 in CFB mode
213 rc2-ecb 128 bit RC2 in ECB mode
214 rc2-ofb 128 bit RC2 in OFB mode
215 rc2-64-cbc 64 bit RC2 in CBC mode
216 rc2-40-cbc 40 bit RC2 in CBC mode
217
218 rc4 128 bit RC4
219 rc4-64 64 bit RC4
220 rc4-40 40 bit RC4
221
222 rc5-cbc RC5 cipher in CBC mode
223 rc5 Alias for rc5-cbc
224 rc5-cfb RC5 cipher in CFB mode
225 rc5-ecb RC5 cipher in ECB mode
226 rc5-ofb RC5 cipher in OFB mode
227
228 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
229 aes-[128|192|256] Alias for aes-[128|192|256]-cbc
230 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
231 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
232 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
233 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
234 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
235
236=head1 EXAMPLES
237
238Just base64 encode a binary file:
239
240 openssl base64 -in file.bin -out file.b64
241
242Decode the same file
243
244 openssl base64 -d -in file.b64 -out file.bin
245
246Encrypt a file using triple DES in CBC mode using a prompted password:
247
248 openssl des3 -salt -in file.txt -out file.des3
249
250Decrypt a file using a supplied password:
251
252 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
253
254Encrypt a file then base64 encode it (so it can be sent via mail for example)
255using Blowfish in CBC mode:
256
257 openssl bf -a -salt -in file.txt -out file.bf
258
259Base64 decode a file then decrypt it:
260
261 openssl bf -d -salt -a -in file.bf -out file.txt
262
263Decrypt some data using a supplied 40 bit RC4 key:
264
265 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
266
267=head1 BUGS
268
269The B<-A> option when used with large files doesn't work properly.
270
271There should be an option to allow an iteration count to be included.
272
273The B<enc> program only supports a fixed number of algorithms with
274certain parameters. So if, for example, you want to use RC2 with a
27576 bit key or RC4 with an 84 bit key you can't use this program.
276
277=cut