1ENC(1) OpenSSL ENC(1)
2
6 enc - symmetric cipher routines
7
9 openssl enc -ciphername [-in filename] [-out filename] [-pass arg] [-e]
10 [-d] [-a/-base64] [-A] [-k password] [-kfile filename] [-K key] [-iv
11 IV] [-S salt] [-salt] [-nosalt] [-z] [-md] [-p] [-P] [-bufsize number]
12 [-nopad] [-debug] [-none] [-engine id]
13
15 The symmetric cipher commands allow data to be encrypted or decrypted
16 using various block and stream ciphers using keys based on passwords or
17 explicitly provided. Base64 encoding or decoding can also be performed
18 either by itself or in addition to the encryption or decryption.
19
21 -in filename
22 the input filename, standard input by default.
23 -out filename
25 the output filename, standard output by default.
26 -pass arg
28 the password source. For more information about the format of arg
29 see the PASS PHRASE ARGUMENTS section in openssl(1).
30 -salt
32 use a salt in the key derivation routines. This is the default.
33 -nosalt
35 don't use a salt in the key derivation routines. This option SHOULD
36 NOT be used except for test purposes or compatibility with ancient
37 versions of OpenSSL and SSLeay.
38 -e encrypt the input data: this is the default.
40 -d decrypt the input data.
42 -a base64 process the data. This means that if encryption is taking
44 place the data is base64 encoded after encryption. If decryption is
45 set then the input data is base64 decoded before being decrypted.
46 -base64
48 same as -a
49 -A if the -a option is set then base64 process the data on one line.
51 -k password
53 the password to derive the key from. This is for compatibility with
54 previous versions of OpenSSL. Superseded by the -pass argument.
55 -kfile filename
57 read the password to derive the key from the first line of
58 filename. This is for compatibility with previous versions of
59 OpenSSL. Superseded by the -pass argument.
60 -nosalt
62 do not use a salt
63 -salt
65 use salt (randomly generated or provide with -S option) when
66 encrypting (this is the default).
67 -S salt
69 the actual salt to use: this must be represented as a string of hex
70 digits.
71 -K key
73 the actual key to use: this must be represented as a string
74 comprised only of hex digits. If only the key is specified, the IV
75 must additionally specified using the -iv option. When both a key
76 and a password are specified, the key given with the -K option will
77 be used and the IV generated from the password will be taken. It
78 probably does not make much sense to specify both key and password.
79 -iv IV
81 the actual IV to use: this must be represented as a string
82 comprised only of hex digits. When only the key is specified using
83 the -K option, the IV must explicitly be defined. When a password
84 is being specified using one of the other options, the IV is
85 generated from this password.
86 -p print out the key and IV used.
88 -P print out the key and IV used then immediately exit: don't do any
90 encryption or decryption.
91 -bufsize number
93 set the buffer size for I/O
94 -nopad
96 disable standard block padding
97 -debug
99 debug the BIOs used for I/O.
100 -z Compress or decompress clear text using zlib before encryption or
102 after decryption. This option exists only if OpenSSL with compiled
103 with zlib or zlib-dynamic option.
104 -none
106 Use NULL cipher (no encryption or decryption of input).
107
109 The program can be called either as openssl ciphername or openssl enc
110 -ciphername. But the first form doesn't work with engine-provided
111 ciphers, because this form is processed before the configuration file
112 is read and any ENGINEs loaded.
113 Engines which provide entirely new encryption algorithms (such as
115 ccgost engine which provides gost89 algorithm) should be configured in
116 the configuration file. Engines, specified in the command line using
117 -engine options can only be used for hadrware-assisted implementations
118 of ciphers, which are supported by OpenSSL core or other engine,
119 specified in the configuration file.
120 When enc command lists supported ciphers, ciphers provided by engines,
122 specified in the configuration files are listed too.
123 A password will be prompted for to derive the key and IV if necessary.
125 The -salt option should ALWAYS be used if the key is being derived from
127 a password unless you want compatibility with previous versions of
128 OpenSSL and SSLeay.
129 Without the -salt option it is possible to perform efficient dictionary
131 attacks on the password and to attack stream cipher encrypted data. The
132 reason for this is that without the salt the same password always
133 generates the same encryption key. When the salt is being used the
134 first eight bytes of the encrypted data are reserved for the salt: it
135 is generated at random when encrypting a file and read from the
136 encrypted file when it is decrypted.
137 Some of the ciphers do not have large keys and others have security
139 implications if not used correctly. A beginner is advised to just use a
140 strong block cipher in CBC mode such as bf or des3.
141 All the block ciphers normally use PKCS#5 padding also known as
143 standard block padding: this allows a rudimentary integrity or password
144 check to be performed. However since the chance of random data passing
145 the test is better than 1 in 256 it isn't a very good test.
146 If padding is disabled then the input data must be a multiple of the
148 cipher block length.
149 All RC2 ciphers have the same key and effective key length.
151 Blowfish and RC5 algorithms use a 128 bit key.
153
155 Note that some of these ciphers can be disabled at compile time and
156 some are available only if an appropriate engine is configured in the
157 configuration file. The output of the enc command run with unsupported
158 options (for example openssl enc -help) includes a list of ciphers,
159 supported by your versesion of OpenSSL, including ones provided by
160 configured engines.
161 base64 Base 64
163 bf-cbc Blowfish in CBC mode
165 bf Alias for bf-cbc
166 bf-cfb Blowfish in CFB mode
167 bf-ecb Blowfish in ECB mode
168 bf-ofb Blowfish in OFB mode
169 cast-cbc CAST in CBC mode
171 cast Alias for cast-cbc
172 cast5-cbc CAST5 in CBC mode
173 cast5-cfb CAST5 in CFB mode
174 cast5-ecb CAST5 in ECB mode
175 cast5-ofb CAST5 in OFB mode
176 des-cbc DES in CBC mode
178 des Alias for des-cbc
179 des-cfb DES in CBC mode
180 des-ofb DES in OFB mode
181 des-ecb DES in ECB mode
182 des-ede-cbc Two key triple DES EDE in CBC mode
184 des-ede Two key triple DES EDE in ECB mode
185 des-ede-cfb Two key triple DES EDE in CFB mode
186 des-ede-ofb Two key triple DES EDE in OFB mode
187 des-ede3-cbc Three key triple DES EDE in CBC mode
189 des-ede3 Three key triple DES EDE in ECB mode
190 des3 Alias for des-ede3-cbc
191 des-ede3-cfb Three key triple DES EDE CFB mode
192 des-ede3-ofb Three key triple DES EDE in OFB mode
193 desx DESX algorithm.
195 gost89 GOST 28147-89 in CFB mode (provided by ccgost engine)
197 gost89-cnt `GOST 28147-89 in CNT mode (provided by ccgost engine)
198 idea-cbc IDEA algorithm in CBC mode
200 idea same as idea-cbc
201 idea-cfb IDEA in CFB mode
202 idea-ecb IDEA in ECB mode
203 idea-ofb IDEA in OFB mode
204 rc2-cbc 128 bit RC2 in CBC mode
206 rc2 Alias for rc2-cbc
207 rc2-cfb 128 bit RC2 in CFB mode
208 rc2-ecb 128 bit RC2 in ECB mode
209 rc2-ofb 128 bit RC2 in OFB mode
210 rc2-64-cbc 64 bit RC2 in CBC mode
211 rc2-40-cbc 40 bit RC2 in CBC mode
212 rc4 128 bit RC4
214 rc4-64 64 bit RC4
215 rc4-40 40 bit RC4
216 rc5-cbc RC5 cipher in CBC mode
218 rc5 Alias for rc5-cbc
219 rc5-cfb RC5 cipher in CFB mode
220 rc5-ecb RC5 cipher in ECB mode
221 rc5-ofb RC5 cipher in OFB mode
222 aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode
224 aes-[128|192|256] Alias for aes-[128|192|256]-cbc
225 aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode
226 aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
227 aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
228 aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode
229 aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode
230
232 Just base64 encode a binary file:
233 openssl base64 -in file.bin -out file.b64
235 Decode the same file
237 openssl base64 -d -in file.b64 -out file.bin
239 Encrypt a file using triple DES in CBC mode using a prompted password:
241 openssl des3 -salt -in file.txt -out file.des3
243 Decrypt a file using a supplied password:
245 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword
247 Encrypt a file then base64 encode it (so it can be sent via mail for
249 example) using Blowfish in CBC mode:
250 openssl bf -a -salt -in file.txt -out file.bf
252 Base64 decode a file then decrypt it:
254 openssl bf -d -salt -a -in file.bf -out file.txt
256 Decrypt some data using a supplied 40 bit RC4 key:
258 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405
260
262 The -A option when used with large files doesn't work properly.
263 There should be an option to allow an iteration count to be included.
265 The enc program only supports a fixed number of algorithms with certain
267 parameters. So if, for example, you want to use RC2 with a 76 bit key
268 or RC4 with an 84 bit key you can't use this program.
2691.0.0e 2009-09-04 ENC(1)