4 enc - symmetric cipher routines
8 B<openssl enc -ciphername>
26 The symmetric cipher commands allow data to be encrytped or decrypted
27 using various block and stream ciphers using keys based on passwords
28 or explicitly provided. Base64 encoding or decoding can also be performed
29 either by itself or in addition to the encryption or decryption.
37 the input filename, standard input by default.
39 =item B<-out filename>
41 the output filename, standard output by default.
45 encrypt the input data: this is the default.
49 decrypt the input data.
53 base64 process the data. This means that if encryption is taking place
54 the data is base64 encoded after encryption. If decryption is set then
55 the input data is base64 decoded before being decrypted.
59 if the B<-a> option is set then base64 process the data on one line.
63 the password to derive the key from.
65 =item B<-kfile filename>
67 read the password to derive the key from the first line of B<filename>
71 the actual key to use: this must be represented as a string comprised only
76 the actual IV to use: this must be represented as a string comprised only
81 print out the key and IV used.
85 print out the key and IV used then immediately exit: don't do any encryption
88 =item B<-bufsize number>
90 set the buffer size for I/O
94 debug the BIOs used for I/O.
100 The program can be called either as B<openssl ciphername> or
101 B<openssl enc -ciphername>.
103 A password will be prompted for to derive the key and IV if necessary.
105 Some of the ciphers do not have large keys and others have security
106 implications if not used correctly. A beginner is advised to just use
107 a strong block cipher in CBC mode such as bf or des3.
109 All the block ciphers use PKCS#5 padding also known as standard block
110 padding: this allows a rudimentary integrity or password check to be
111 performed. However since the chance of random data passing the test is
112 better than 1 in 256 it isn't a very good test.
114 All RC2 ciphers have the same key and effective key length.
116 Blowfish and RC5 algorithms use a 128 bit key.
118 =head1 SUPPORTED CIPHERS
122 bf-cbc Blowfish in CBC mode
124 bf-cfb Blowish in CFB mode
125 bf-ecb Blowfish in ECB mode
126 bf-ofb Blowfish in OFB mode
128 cast-cbc CAST in CBC mode
129 cast Alias for cast-cbc
130 cast5-cbc CAST5 in CBC mode
131 cast5-cfb CAST5 in CFB mode
132 cast5-ecb CAST5 in ECB mode
133 cast5-ofb CAST5 in OFB mode
135 des-cbc DES in CBC mode
136 des Alias for des-cbc
137 des-cfb DES in CBC mode
138 des-ofb DES in OFB mode
139 des-ecb DES in ECB mode
141 des-ede-cbc Two key triple DES EDE in CBC mode
142 des-ede Alias for des-ede
143 des-ede-cfb Two key triple DES EDE in CFB mode
144 des-ede-ofb Two key triple DES EDE in OFB mode
146 des-ede3-cbc Three key triple DES EDE in CBC mode
147 des-ede3 Alias for des-ede3-cbc
148 des3 Alias for des-ede3-cbc
149 des-ede3-cfb Three key triple DES EDE CFB mode
150 des-ede3-ofb Three key triple DES EDE in OFB mode
154 idea-cbc IDEA algorithm in CBC mode
155 idea same as idea-cbc
156 idea-cfb IDEA in CFB mode
157 idea-ecb IDEA in ECB mode
158 idea-ofb IDEA in OFB mode
160 rc2-cbc 128 bit RC2 in CBC mode
161 rc2 Alias for rc2-cbc
162 rc2-cfb 128 bit RC2 in CBC mode
163 rc2-ecb 128 bit RC2 in CBC mode
164 rc2-ofb 128 bit RC2 in CBC mode
165 rc2-64-cbc 64 bit RC2 in CBC mode
166 rc2-40-cbc 40 bit RC2 in CBC mode
172 rc5-cbc RC5 cipher in CBC mode
173 rc5 Alias for rc5-cbc
174 rc5-cfb RC5 cipher in CBC mode
175 rc5-ecb RC5 cipher in CBC mode
176 rc5-ofb RC5 cipher in CBC mode
180 Just base64 encode a binary file:
182 openssl base64 -in file.bin -out file.b64
186 openssl base64 -d -in file.b64 -out file.bin
188 Encrypt a file using triple DES in CBC mode using a prompted password:
190 openssl des3 -in file.txt -out file.des3
192 Decrypt a file using a supplied password:
194 openssl des3 -d -in file.des3 -out file.txt -k mypassword
196 Encrypt a file then base64 encode it (so it can be sent via mail for example)
197 using Blowfish in CBC mode:
199 openssl bf -a -in file.txt -out file.bf
201 Base64 decode a file then decrypt it:
203 openssl bf -d -a -in file.bf -out file.txt
205 Decrypt some data using a supplied 40 bit RC4 key:
207 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
211 The B<-A> option when used with large files doesn't work properly.
213 The key derivation algorithm used is compatible with the SSLeay algorithm. It
214 is not very good: it uses unsalted MD5.
216 There should be an option to allow a salt or iteration count to be included.
218 Like the EVP library the B<enc> program only supports a fixed number of
219 algorithms with certain parameters. So if, for example, you want to use RC2
220 with a 76 bit key or RC4 with an 84 bit key you can't use this program.