Remove README.DRAGONFLY from vendor branch
[dragonfly.git] / crypto / openssl / doc / apps / enc.pod
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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
53use a salt in the key derivation routines. This option should B<ALWAYS>
54be used unless compatibility with previous versions of OpenSSL or SSLeay
55is required. This option is only present on OpenSSL versions 0.9.5 or
56above.
57
58=item B<-nosalt>
59
60don't use a salt in the key derivation routines. This is the default for
61compatibility with previous versions of OpenSSL and SSLeay.
62
63=item B<-e>
64
65encrypt the input data: this is the default.
66
67=item B<-d>
68
69decrypt the input data.
70
71=item B<-a>
72
73base64 process the data. This means that if encryption is taking place
74the data is base64 encoded after encryption. If decryption is set then
75the input data is base64 decoded before being decrypted.
76
77=item B<-A>
78
79if the B<-a> option is set then base64 process the data on one line.
80
81=item B<-k password>
82
83the password to derive the key from. This is for compatibility with previous
84versions of OpenSSL. Superseded by the B<-pass> argument.
85
86=item B<-kfile filename>
87
88read the password to derive the key from the first line of B<filename>.
89This is for compatibility with previous versions of OpenSSL. Superseded by
90the B<-pass> argument.
91
92=item B<-S salt>
93
94the actual salt to use: this must be represented as a string comprised only
95of hex digits.
96
97=item B<-K key>
98
99the actual key to use: this must be represented as a string comprised only
100of hex digits. If only the key is specified, the IV must additionally specified
101using the B<-iv> option. When both a key and a password are specified, the
102key given with the B<-K> option will be used and the IV generated from the
103password will be taken. It probably does not make much sense to specify
104both key and password.
105
106=item B<-iv IV>
107
108the actual IV to use: this must be represented as a string comprised only
109of hex digits. When only the key is specified using the B<-K> option, the
110IV must explicitly be defined. When a password is being specified using
111one of the other options, the IV is generated from this password.
112
113=item B<-p>
114
115print out the key and IV used.
116
117=item B<-P>
118
119print out the key and IV used then immediately exit: don't do any encryption
120or decryption.
121
122=item B<-bufsize number>
123
124set the buffer size for I/O
125
126=item B<-nopad>
127
128disable standard block padding
129
130=item B<-debug>
131
132debug the BIOs used for I/O.
133
134=back
135
136=head1 NOTES
137
138The program can be called either as B<openssl ciphername> or
139B<openssl enc -ciphername>.
140
141A password will be prompted for to derive the key and IV if necessary.
142
143The B<-salt> option should B<ALWAYS> be used if the key is being derived
144from a password unless you want compatibility with previous versions of
145OpenSSL and SSLeay.
146
147Without the B<-salt> option it is possible to perform efficient dictionary
148attacks on the password and to attack stream cipher encrypted data. The reason
149for this is that without the salt the same password always generates the same
150encryption key. When the salt is being used the first eight bytes of the
151encrypted data are reserved for the salt: it is generated at random when
152encrypting a file and read from the encrypted file when it is decrypted.
153
154Some of the ciphers do not have large keys and others have security
155implications if not used correctly. A beginner is advised to just use
156a strong block cipher in CBC mode such as bf or des3.
157
158All the block ciphers normally use PKCS#5 padding also known as standard block
159padding: this allows a rudimentary integrity or password check to be
160performed. However since the chance of random data passing the test is
161better than 1 in 256 it isn't a very good test.
162
163If padding is disabled then the input data must be a multiple of the cipher
164block length.
165
166All RC2 ciphers have the same key and effective key length.
167
168Blowfish and RC5 algorithms use a 128 bit key.
169
170=head1 SUPPORTED CIPHERS
171
172 base64 Base 64
173
174 bf-cbc Blowfish in CBC mode
175 bf Alias for bf-cbc
176 bf-cfb Blowfish in CFB mode
177 bf-ecb Blowfish in ECB mode
178 bf-ofb Blowfish in OFB mode
179
180 cast-cbc CAST in CBC mode
181 cast Alias for cast-cbc
182 cast5-cbc CAST5 in CBC mode
183 cast5-cfb CAST5 in CFB mode
184 cast5-ecb CAST5 in ECB mode
185 cast5-ofb CAST5 in OFB mode
186
187 des-cbc DES in CBC mode
188 des Alias for des-cbc
189 des-cfb DES in CBC mode
190 des-ofb DES in OFB mode
191 des-ecb DES in ECB mode
192
193 des-ede-cbc Two key triple DES EDE in CBC mode
194 des-ede Two key triple DES EDE in ECB mode
195 des-ede-cfb Two key triple DES EDE in CFB mode
196 des-ede-ofb Two key triple DES EDE in OFB mode
197
198 des-ede3-cbc Three key triple DES EDE in CBC mode
199 des-ede3 Three key triple DES EDE in ECB mode
200 des3 Alias for des-ede3-cbc
201 des-ede3-cfb Three key triple DES EDE CFB mode
202 des-ede3-ofb Three key triple DES EDE in OFB mode
203
204 desx DESX algorithm.
205
206 idea-cbc IDEA algorithm in CBC mode
207 idea same as idea-cbc
208 idea-cfb IDEA in CFB mode
209 idea-ecb IDEA in ECB mode
210 idea-ofb IDEA in OFB mode
211
212 rc2-cbc 128 bit RC2 in CBC mode
213 rc2 Alias for rc2-cbc
214 rc2-cfb 128 bit RC2 in CFB mode
215 rc2-ecb 128 bit RC2 in ECB mode
216 rc2-ofb 128 bit RC2 in OFB mode
217 rc2-64-cbc 64 bit RC2 in CBC mode
218 rc2-40-cbc 40 bit RC2 in CBC mode
219
220 rc4 128 bit RC4
221 rc4-64 64 bit RC4
222 rc4-40 40 bit RC4
223
224 rc5-cbc RC5 cipher in CBC mode
225 rc5 Alias for rc5-cbc
226 rc5-cfb RC5 cipher in CFB mode
227 rc5-ecb RC5 cipher in ECB mode
228 rc5-ofb RC5 cipher in OFB mode
229
230 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
231 aes-[128|192|256] Alias for aes-[128|192|256]-cbc
232 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
233 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
234 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
235 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
236 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
237
238=head1 EXAMPLES
239
240Just base64 encode a binary file:
241
242 openssl base64 -in file.bin -out file.b64
243
244Decode the same file
245
246 openssl base64 -d -in file.b64 -out file.bin
247
248Encrypt a file using triple DES in CBC mode using a prompted password:
249
250 openssl des3 -salt -in file.txt -out file.des3
251
252Decrypt a file using a supplied password:
253
254 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
255
256Encrypt a file then base64 encode it (so it can be sent via mail for example)
257using Blowfish in CBC mode:
258
259 openssl bf -a -salt -in file.txt -out file.bf
260
261Base64 decode a file then decrypt it:
262
263 openssl bf -d -salt -a -in file.bf -out file.txt
264
265Decrypt some data using a supplied 40 bit RC4 key:
266
267 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
268
269=head1 BUGS
270
271The B<-A> option when used with large files doesn't work properly.
272
273There should be an option to allow an iteration count to be included.
274
275The B<enc> program only supports a fixed number of algorithms with
276certain parameters. So if, for example, you want to use RC2 with a
27776 bit key or RC4 with an 84 bit key you can't use this program.
278
279=cut