doc/man1/openssl-enc.pod.in

   1 =pod
   2
   3 =begin comment
   4 {- join("\n", @autowarntext) -}
   5
   6 =end comment
   7
   8 =head1 NAME
   9
  10 openssl-enc - symmetric cipher routines
  11
  12 =head1 SYNOPSIS
  13
  14 B<openssl> B<enc>|I<cipher>
  15 [B<-I<cipher>>]
  16 [B<-help>]
  17 [B<-list>]
  18 [B<-ciphers>]
  19 [B<-in> I<filename>]
  20 [B<-out> I<filename>]
  21 [B<-pass> I<arg>]
  22 [B<-e>]
  23 [B<-d>]
  24 [B<-a>]
  25 [B<-base64>]
  26 [B<-A>]
  27 [B<-k> I<password>]
  28 [B<-kfile> I<filename>]
  29 [B<-K> I<key>]
  30 [B<-iv> I<IV>]
  31 [B<-S> I<salt>]
  32 [B<-salt>]
  33 [B<-nosalt>]
  34 [B<-z>]
  35 [B<-md> I<digest>]
  36 [B<-iter> I<count>]
  37 [B<-pbkdf2>]
  38 [B<-p>]
  39 [B<-P>]
  40 [B<-bufsize> I<number>]
  41 [B<-nopad>]
  42 [B<-debug>]
  43 [B<-none>]
  44 [B<-engine> I<id>]
  45 {- $OpenSSL::safe::opt_r_synopsis -}
  46
  47 =for openssl ifdef z engine
  48
  49 B<openssl> I<cipher> [B<...>]
  50
  51 =head1 DESCRIPTION
  52
  53 The symmetric cipher commands allow data to be encrypted or decrypted
  54 using various block and stream ciphers using keys based on passwords
  55 or explicitly provided. Base64 encoding or decoding can also be performed
  56 either by itself or in addition to the encryption or decryption.
  57
  58 =head1 OPTIONS
  59
  60 =over 4
  61
  62 =item B<-help>
  63
  64 Print out a usage message.
  65
  66 =item B<-list>
  67
  68 List all supported ciphers.
  69
  70 =item B<-ciphers>
  71
  72 Alias of -list to display all supported ciphers.
  73
  74 =item B<-in> I<filename>
  75
  76 The input filename, standard input by default.
  77
  78 =item B<-out> I<filename>
  79
  80 The output filename, standard output by default.
  81
  82 =item B<-pass> I<arg>
  83
  84 The password source. For more information about the format of I<arg>
  85 see L<openssl(1)/Pass Phrase Options>.
  86
  87 =item B<-e>
  88
  89 Encrypt the input data: this is the default.
  90
  91 =item B<-d>
  92
  93 Decrypt the input data.
  94
  95 =item B<-a>
  96
  97 Base64 process the data. This means that if encryption is taking place
  98 the data is base64 encoded after encryption. If decryption is set then
  99 the input data is base64 decoded before being decrypted.
 100
 101 =item B<-base64>
 102
 103 Same as B<-a>
 104
 105 =item B<-A>
 106
 107 If the B<-a> option is set then base64 process the data on one line.
 108
 109 =item B<-k> I<password>
 110
 111 The password to derive the key from. This is for compatibility with previous
 112 versions of OpenSSL. Superseded by the B<-pass> argument.
 113
 114 =item B<-kfile> I<filename>
 115
 116 Read the password to derive the key from the first line of I<filename>.
 117 This is for compatibility with previous versions of OpenSSL. Superseded by
 118 the B<-pass> argument.
 119
 120 =item B<-md> I<digest>
 121
 122 Use the specified digest to create the key from the passphrase.
 123 The default algorithm is sha-256.
 124
 125 =item B<-iter> I<count>
 126
 127 Use a given number of iterations on the password in deriving the encryption key.
 128 High values increase the time required to brute-force the resulting file.
 129 This option enables the use of PBKDF2 algorithm to derive the key.
 130
 131 =item B<-pbkdf2>
 132
 133 Use PBKDF2 algorithm with default iteration count unless otherwise specified.
 134
 135 =item B<-nosalt>
 136
 137 Don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
 138 used except for test purposes or compatibility with ancient versions of
 139 OpenSSL.
 140
 141 =item B<-salt>
 142
 143 Use salt (randomly generated or provide with B<-S> option) when
 144 encrypting, this is the default.
 145
 146 =item B<-S> I<salt>
 147
 148 The actual salt to use: this must be represented as a string of hex digits.
 149
 150 =item B<-K> I<key>
 151
 152 The actual key to use: this must be represented as a string comprised only
 153 of hex digits. If only the key is specified, the IV must additionally specified
 154 using the B<-iv> option. When both a key and a password are specified, the
 155 key given with the B<-K> option will be used and the IV generated from the
 156 password will be taken. It does not make much sense to specify both key
 157 and password.
 158
 159 =item B<-iv> I<IV>
 160
 161 The actual IV to use: this must be represented as a string comprised only
 162 of hex digits. When only the key is specified using the B<-K> option, the
 163 IV must explicitly be defined. When a password is being specified using
 164 one of the other options, the IV is generated from this password.
 165
 166 =item B<-p>
 167
 168 Print out the key and IV used.
 169
 170 =item B<-P>
 171
 172 Print out the key and IV used then immediately exit: don't do any encryption
 173 or decryption.
 174
 175 =item B<-bufsize> I<number>
 176
 177 Set the buffer size for I/O.
 178
 179 =item B<-nopad>
 180
 181 Disable standard block padding.
 182
 183 =item B<-debug>
 184
 185 Debug the BIOs used for I/O.
 186
 187 =item B<-z>
 188
 189 Compress or decompress clear text using zlib before encryption or after
 190 decryption. This option exists only if OpenSSL with compiled with zlib
 191 or zlib-dynamic option.
 192
 193 =item B<-none>
 194
 195 Use NULL cipher (no encryption or decryption of input).
 196
 197 {- $OpenSSL::safe::opt_r_item -}
 198
 199 =back
 200
 201 =head1 NOTES
 202
 203 The program can be called either as C<openssl I<cipher>> or
 204 C<openssl enc -I<cipher>>. The first form doesn't work with
 205 engine-provided ciphers, because this form is processed before the
 206 configuration file is read and any ENGINEs loaded.
 207 Use the L<openssl-list(1)> command to get a list of supported ciphers.
 208
 209 Engines which provide entirely new encryption algorithms (such as the ccgost
 210 engine which provides gost89 algorithm) should be configured in the
 211 configuration file. Engines specified on the command line using -engine
 212 options can only be used for hardware-assisted implementations of
 213 ciphers which are supported by the OpenSSL core or another engine specified
 214 in the configuration file.
 215
 216 When the enc command lists supported ciphers, ciphers provided by engines,
 217 specified in the configuration files are listed too.
 218
 219 A password will be prompted for to derive the key and IV if necessary.
 220
 221 The B<-salt> option should B<ALWAYS> be used if the key is being derived
 222 from a password unless you want compatibility with previous versions of
 223 OpenSSL.
 224
 225 Without the B<-salt> option it is possible to perform efficient dictionary
 226 attacks on the password and to attack stream cipher encrypted data. The reason
 227 for this is that without the salt the same password always generates the same
 228 encryption key. When the salt is being used the first eight bytes of the
 229 encrypted data are reserved for the salt: it is generated at random when
 230 encrypting a file and read from the encrypted file when it is decrypted.
 231
 232 Some of the ciphers do not have large keys and others have security
 233 implications if not used correctly. A beginner is advised to just use
 234 a strong block cipher, such as AES, in CBC mode.
 235
 236 All the block ciphers normally use PKCS#5 padding, also known as standard
 237 block padding. This allows a rudimentary integrity or password check to
 238 be performed. However since the chance of random data passing the test
 239 is better than 1 in 256 it isn't a very good test.
 240
 241 If padding is disabled then the input data must be a multiple of the cipher
 242 block length.
 243
 244 All RC2 ciphers have the same key and effective key length.
 245
 246 Blowfish and RC5 algorithms use a 128 bit key.
 247
 248 =head1 SUPPORTED CIPHERS
 249
 250 Note that some of these ciphers can be disabled at compile time
 251 and some are available only if an appropriate engine is configured
 252 in the configuration file. The output when invoking this command
 253 with the B<-ciphers> option (that is C<openssl enc -ciphers>) is
 254 a list of ciphers, supported by your version of OpenSSL, including
 255 ones provided by configured engines.
 256
 257 This command does not support authenticated encryption modes
 258 like CCM and GCM, and will not support such modes in the future.
 259 This is due to having to begin streaming output (e.g., to standard output
 260 when B<-out> is not used) before the authentication tag could be validated.
 261 When this command is used in a pipeline, the receiveing end will not be
 262 able to roll back upon authentication failure.  The AEAD modes currently in
 263 common use also suffer from catastrophic failure of confidentiality and/or
 264 integrity upon reuse of key/iv/nonce, and since B<openssl enc> places the
 265 entire burden of key/iv/nonce management upon the user, the risk of
 266 exposing AEAD modes is too great to allow.  These key/iv/nonce
 267 management issues also affect other modes currently exposed in this command,
 268 but the failure modes are less extreme in these cases, and the
 269 functionality cannot be removed with a stable release branch.
 270 For bulk encryption of data, whether using authenticated encryption
 271 modes or other modes, L<openssl-cms(1)> is recommended, as it provides a
 272 standard data format and performs the needed key/iv/nonce management.
 273
 274
 275  base64             Base 64
 276
 277  bf-cbc             Blowfish in CBC mode
 278  bf                 Alias for bf-cbc
 279  blowfish           Alias for bf-cbc
 280  bf-cfb             Blowfish in CFB mode
 281  bf-ecb             Blowfish in ECB mode
 282  bf-ofb             Blowfish in OFB mode
 283
 284  cast-cbc           CAST in CBC mode
 285  cast               Alias for cast-cbc
 286  cast5-cbc          CAST5 in CBC mode
 287  cast5-cfb          CAST5 in CFB mode
 288  cast5-ecb          CAST5 in ECB mode
 289  cast5-ofb          CAST5 in OFB mode
 290
 291  chacha20           ChaCha20 algorithm
 292
 293  des-cbc            DES in CBC mode
 294  des                Alias for des-cbc
 295  des-cfb            DES in CFB mode
 296  des-ofb            DES in OFB mode
 297  des-ecb            DES in ECB mode
 298
 299  des-ede-cbc        Two key triple DES EDE in CBC mode
 300  des-ede            Two key triple DES EDE in ECB mode
 301  des-ede-cfb        Two key triple DES EDE in CFB mode
 302  des-ede-ofb        Two key triple DES EDE in OFB mode
 303
 304  des-ede3-cbc       Three key triple DES EDE in CBC mode
 305  des-ede3           Three key triple DES EDE in ECB mode
 306  des3               Alias for des-ede3-cbc
 307  des-ede3-cfb       Three key triple DES EDE CFB mode
 308  des-ede3-ofb       Three key triple DES EDE in OFB mode
 309
 310  desx               DESX algorithm.
 311
 312  gost89             GOST 28147-89 in CFB mode (provided by ccgost engine)
 313  gost89-cnt        `GOST 28147-89 in CNT mode (provided by ccgost engine)
 314
 315  idea-cbc           IDEA algorithm in CBC mode
 316  idea               same as idea-cbc
 317  idea-cfb           IDEA in CFB mode
 318  idea-ecb           IDEA in ECB mode
 319  idea-ofb           IDEA in OFB mode
 320
 321  rc2-cbc            128 bit RC2 in CBC mode
 322  rc2                Alias for rc2-cbc
 323  rc2-cfb            128 bit RC2 in CFB mode
 324  rc2-ecb            128 bit RC2 in ECB mode
 325  rc2-ofb            128 bit RC2 in OFB mode
 326  rc2-64-cbc         64 bit RC2 in CBC mode
 327  rc2-40-cbc         40 bit RC2 in CBC mode
 328
 329  rc4                128 bit RC4
 330  rc4-64             64 bit RC4
 331  rc4-40             40 bit RC4
 332
 333  rc5-cbc            RC5 cipher in CBC mode
 334  rc5                Alias for rc5-cbc
 335  rc5-cfb            RC5 cipher in CFB mode
 336  rc5-ecb            RC5 cipher in ECB mode
 337  rc5-ofb            RC5 cipher in OFB mode
 338
 339  seed-cbc           SEED cipher in CBC mode
 340  seed               Alias for seed-cbc
 341  seed-cfb           SEED cipher in CFB mode
 342  seed-ecb           SEED cipher in ECB mode
 343  seed-ofb           SEED cipher in OFB mode
 344
 345  sm4-cbc            SM4 cipher in CBC mode
 346  sm4                Alias for sm4-cbc
 347  sm4-cfb            SM4 cipher in CFB mode
 348  sm4-ctr            SM4 cipher in CTR mode
 349  sm4-ecb            SM4 cipher in ECB mode
 350  sm4-ofb            SM4 cipher in OFB mode
 351
 352  aes-[128|192|256]-cbc  128/192/256 bit AES in CBC mode
 353  aes[128|192|256]       Alias for aes-[128|192|256]-cbc
 354  aes-[128|192|256]-cfb  128/192/256 bit AES in 128 bit CFB mode
 355  aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
 356  aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
 357  aes-[128|192|256]-ctr  128/192/256 bit AES in CTR mode
 358  aes-[128|192|256]-ecb  128/192/256 bit AES in ECB mode
 359  aes-[128|192|256]-ofb  128/192/256 bit AES in OFB mode
 360
 361  aria-[128|192|256]-cbc  128/192/256 bit ARIA in CBC mode
 362  aria[128|192|256]       Alias for aria-[128|192|256]-cbc
 363  aria-[128|192|256]-cfb  128/192/256 bit ARIA in 128 bit CFB mode
 364  aria-[128|192|256]-cfb1 128/192/256 bit ARIA in 1 bit CFB mode
 365  aria-[128|192|256]-cfb8 128/192/256 bit ARIA in 8 bit CFB mode
 366  aria-[128|192|256]-ctr  128/192/256 bit ARIA in CTR mode
 367  aria-[128|192|256]-ecb  128/192/256 bit ARIA in ECB mode
 368  aria-[128|192|256]-ofb  128/192/256 bit ARIA in OFB mode
 369
 370  camellia-[128|192|256]-cbc  128/192/256 bit Camellia in CBC mode
 371  camellia[128|192|256]       Alias for camellia-[128|192|256]-cbc
 372  camellia-[128|192|256]-cfb  128/192/256 bit Camellia in 128 bit CFB mode
 373  camellia-[128|192|256]-cfb1 128/192/256 bit Camellia in 1 bit CFB mode
 374  camellia-[128|192|256]-cfb8 128/192/256 bit Camellia in 8 bit CFB mode
 375  camellia-[128|192|256]-ctr  128/192/256 bit Camellia in CTR mode
 376  camellia-[128|192|256]-ecb  128/192/256 bit Camellia in ECB mode
 377  camellia-[128|192|256]-ofb  128/192/256 bit Camellia in OFB mode
 378
 379 =head1 EXAMPLES
 380
 381 Just base64 encode a binary file:
 382
 383  openssl base64 -in file.bin -out file.b64
 384
 385 Decode the same file
 386
 387  openssl base64 -d -in file.b64 -out file.bin
 388
 389 Encrypt a file using AES-128 using a prompted password
 390 and PBKDF2 key derivation:
 391
 392  openssl enc -aes128 -pbkdf2 -in file.txt -out file.aes128
 393
 394 Decrypt a file using a supplied password:
 395
 396  openssl enc -aes128 -pbkdf2 -d -in file.aes128 -out file.txt \
 397     -pass pass:<password>
 398
 399 Encrypt a file then base64 encode it (so it can be sent via mail for example)
 400 using AES-256 in CTR mode and PBKDF2 key derivation:
 401
 402  openssl enc -aes-256-ctr -pbkdf2 -a -in file.txt -out file.aes256
 403
 404 Base64 decode a file then decrypt it using a password supplied in a file:
 405
 406  openssl enc -aes-256-ctr -pbkdf2 -d -a -in file.aes256 -out file.txt \
 407     -pass file:<passfile>
 408
 409 =head1 BUGS
 410
 411 The B<-A> option when used with large files doesn't work properly.
 412
 413 The B<openssl enc> command only supports a fixed number of algorithms with
 414 certain parameters. So if, for example, you want to use RC2 with a
 415 76 bit key or RC4 with an 84 bit key you can't use this program.
 416
 417 =head1 HISTORY
 418
 419 The default digest was changed from MD5 to SHA256 in OpenSSL 1.1.0.
 420
 421 The B<-list> option was added in OpenSSL 1.1.1e.
 422
 423 The B<-ciphers> option was deprecated in OpenSSL 3.0.
 424
 425 =head1 COPYRIGHT
 426
 427 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
 428
 429 Licensed under the Apache License 2.0 (the "License").  You may not use
 430 this file except in compliance with the License.  You can obtain a copy
 431 in the file LICENSE in the source distribution or at
 432 L<https://www.openssl.org/source/license.html>.
 433
 434 =cut