doc/man1/openssl-enc.pod.in

   1 =pod
   2 {- OpenSSL::safe::output_do_not_edit_headers(); -}
   3
   4 =head1 NAME
   5
   6 openssl-enc - symmetric cipher routines
   7
   8 =head1 SYNOPSIS
   9
  10 B<openssl> B<enc>|I<cipher>
  11 [B<-I<cipher>>]
  12 [B<-help>]
  13 [B<-list>]
  14 [B<-ciphers>]
  15 [B<-in> I<filename>]
  16 [B<-out> I<filename>]
  17 [B<-pass> I<arg>]
  18 [B<-e>]
  19 [B<-d>]
  20 [B<-a>]
  21 [B<-base64>]
  22 [B<-A>]
  23 [B<-k> I<password>]
  24 [B<-kfile> I<filename>]
  25 [B<-K> I<key>]
  26 [B<-iv> I<IV>]
  27 [B<-S> I<salt>]
  28 [B<-salt>]
  29 [B<-nosalt>]
  30 [B<-z>]
  31 [B<-md> I<digest>]
  32 [B<-iter> I<count>]
  33 [B<-pbkdf2>]
  34 [B<-p>]
  35 [B<-P>]
  36 [B<-bufsize> I<number>]
  37 [B<-nopad>]
  38 [B<-v>]
  39 [B<-debug>]
  40 [B<-none>]
  41 {- $OpenSSL::safe::opt_engine_synopsis -}
  42 {- $OpenSSL::safe::opt_r_synopsis -}
  43 {- $OpenSSL::safe::opt_provider_synopsis -}
  44
  45 =for openssl ifdef z engine ciphers
  46
  47 B<openssl> I<cipher> [B<...>]
  48
  49 =head1 DESCRIPTION
  50
  51 The symmetric cipher commands allow data to be encrypted or decrypted
  52 using various block and stream ciphers using keys based on passwords
  53 or explicitly provided. Base64 encoding or decoding can also be performed
  54 either by itself or in addition to the encryption or decryption.
  55
  56 =head1 OPTIONS
  57
  58 =over 4
  59
  60 =item B<-help>
  61
  62 Print out a usage message.
  63
  64 =item B<-list>
  65
  66 List all supported ciphers.
  67
  68 =item B<-ciphers>
  69
  70 Alias of -list to display all supported ciphers.
  71
  72 =item B<-in> I<filename>
  73
  74 The input filename, standard input by default.
  75
  76 =item B<-out> I<filename>
  77
  78 The output filename, standard output by default.
  79
  80 =item B<-pass> I<arg>
  81
  82 The password source. For more information about the format of I<arg>
  83 see L<openssl(1)/Pass Phrase Options>.
  84
  85 =item B<-e>
  86
  87 Encrypt the input data: this is the default.
  88
  89 =item B<-d>
  90
  91 Decrypt the input data.
  92
  93 =item B<-a>
  94
  95 Base64 process the data. This means that if encryption is taking place
  96 the data is base64 encoded after encryption. If decryption is set then
  97 the input data is base64 decoded before being decrypted.
  98
  99 =item B<-base64>
 100
 101 Same as B<-a>
 102
 103 =item B<-A>
 104
 105 If the B<-a> option is set then base64 process the data on one line.
 106
 107 =item B<-k> I<password>
 108
 109 The password to derive the key from. This is for compatibility with previous
 110 versions of OpenSSL. Superseded by the B<-pass> argument.
 111
 112 =item B<-kfile> I<filename>
 113
 114 Read the password to derive the key from the first line of I<filename>.
 115 This is for compatibility with previous versions of OpenSSL. Superseded by
 116 the B<-pass> argument.
 117
 118 =item B<-md> I<digest>
 119
 120 Use the specified digest to create the key from the passphrase.
 121 The default algorithm is sha-256.
 122
 123 =item B<-iter> I<count>
 124
 125 Use a given number of iterations on the password in deriving the encryption key.
 126 High values increase the time required to brute-force the resulting file.
 127 This option enables the use of PBKDF2 algorithm to derive the key.
 128
 129 =item B<-pbkdf2>
 130
 131 Use PBKDF2 algorithm with default iteration count unless otherwise specified.
 132
 133 =item B<-nosalt>
 134
 135 Don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
 136 used except for test purposes or compatibility with ancient versions of
 137 OpenSSL.
 138
 139 =item B<-salt>
 140
 141 Use salt (randomly generated or provide with B<-S> option) when
 142 encrypting, this is the default.
 143
 144 =item B<-S> I<salt>
 145
 146 The actual salt to use: this must be represented as a string of hex digits.
 147
 148 =item B<-K> I<key>
 149
 150 The actual key to use: this must be represented as a string comprised only
 151 of hex digits. If only the key is specified, the IV must additionally specified
 152 using the B<-iv> option. When both a key and a password are specified, the
 153 key given with the B<-K> option will be used and the IV generated from the
 154 password will be taken. It does not make much sense to specify both key
 155 and password.
 156
 157 =item B<-iv> I<IV>
 158
 159 The actual IV to use: this must be represented as a string comprised only
 160 of hex digits. When only the key is specified using the B<-K> option, the
 161 IV must explicitly be defined. When a password is being specified using
 162 one of the other options, the IV is generated from this password.
 163
 164 =item B<-p>
 165
 166 Print out the key and IV used.
 167
 168 =item B<-P>
 169
 170 Print out the key and IV used then immediately exit: don't do any encryption
 171 or decryption.
 172
 173 =item B<-bufsize> I<number>
 174
 175 Set the buffer size for I/O.
 176
 177 =item B<-nopad>
 178
 179 Disable standard block padding.
 180
 181 =item B<-v>
 182
 183 Verbose print; display some statistics about I/O and buffer sizes.
 184
 185 =item B<-debug>
 186
 187 Debug the BIOs used for I/O.
 188
 189 =item B<-z>
 190
 191 Compress or decompress clear text using zlib before encryption or after
 192 decryption. This option exists only if OpenSSL with compiled with zlib
 193 or zlib-dynamic option.
 194
 195 =item B<-none>
 196
 197 Use NULL cipher (no encryption or decryption of input).
 198
 199 {- $OpenSSL::safe::opt_r_item -}
 200
 201 {- $OpenSSL::safe::opt_provider_item -}
 202
 203 {- $OpenSSL::safe::opt_engine_item -}
 204
 205 =back
 206
 207 =head1 NOTES
 208
 209 The program can be called either as C<openssl I<cipher>> or
 210 C<openssl enc -I<cipher>>. The first form doesn't work with
 211 engine-provided ciphers, because this form is processed before the
 212 configuration file is read and any ENGINEs loaded.
 213 Use the L<openssl-list(1)> command to get a list of supported ciphers.
 214
 215 Engines which provide entirely new encryption algorithms (such as the ccgost
 216 engine which provides gost89 algorithm) should be configured in the
 217 configuration file. Engines specified on the command line using B<-engine>
 218 option can only be used for hardware-assisted implementations of
 219 ciphers which are supported by the OpenSSL core or another engine specified
 220 in the configuration file.
 221
 222 When the enc command lists supported ciphers, ciphers provided by engines,
 223 specified in the configuration files are listed too.
 224
 225 A password will be prompted for to derive the key and IV if necessary.
 226
 227 The B<-salt> option should B<ALWAYS> be used if the key is being derived
 228 from a password unless you want compatibility with previous versions of
 229 OpenSSL.
 230
 231 Without the B<-salt> option it is possible to perform efficient dictionary
 232 attacks on the password and to attack stream cipher encrypted data. The reason
 233 for this is that without the salt the same password always generates the same
 234 encryption key. When the salt is being used the first eight bytes of the
 235 encrypted data are reserved for the salt: it is generated at random when
 236 encrypting a file and read from the encrypted file when it is decrypted.
 237
 238 Some of the ciphers do not have large keys and others have security
 239 implications if not used correctly. A beginner is advised to just use
 240 a strong block cipher, such as AES, in CBC mode.
 241
 242 All the block ciphers normally use PKCS#5 padding, also known as standard
 243 block padding. This allows a rudimentary integrity or password check to
 244 be performed. However since the chance of random data passing the test
 245 is better than 1 in 256 it isn't a very good test.
 246
 247 If padding is disabled then the input data must be a multiple of the cipher
 248 block length.
 249
 250 All RC2 ciphers have the same key and effective key length.
 251
 252 Blowfish and RC5 algorithms use a 128 bit key.
 253
 254 =head1 SUPPORTED CIPHERS
 255
 256 Note that some of these ciphers can be disabled at compile time
 257 and some are available only if an appropriate engine is configured
 258 in the configuration file. The output when invoking this command
 259 with the B<-ciphers> option (that is C<openssl enc -ciphers>) is
 260 a list of ciphers, supported by your version of OpenSSL, including
 261 ones provided by configured engines.
 262
 263 This command does not support authenticated encryption modes
 264 like CCM and GCM, and will not support such modes in the future.
 265 This is due to having to begin streaming output (e.g., to standard output
 266 when B<-out> is not used) before the authentication tag could be validated.
 267 When this command is used in a pipeline, the receiving end will not be
 268 able to roll back upon authentication failure.  The AEAD modes currently in
 269 common use also suffer from catastrophic failure of confidentiality and/or
 270 integrity upon reuse of key/iv/nonce, and since B<openssl enc> places the
 271 entire burden of key/iv/nonce management upon the user, the risk of
 272 exposing AEAD modes is too great to allow.  These key/iv/nonce
 273 management issues also affect other modes currently exposed in this command,
 274 but the failure modes are less extreme in these cases, and the
 275 functionality cannot be removed with a stable release branch.
 276 For bulk encryption of data, whether using authenticated encryption
 277 modes or other modes, L<openssl-cms(1)> is recommended, as it provides a
 278 standard data format and performs the needed key/iv/nonce management.
 279
 280
 281  base64             Base 64
 282
 283  bf-cbc             Blowfish in CBC mode
 284  bf                 Alias for bf-cbc
 285  blowfish           Alias for bf-cbc
 286  bf-cfb             Blowfish in CFB mode
 287  bf-ecb             Blowfish in ECB mode
 288  bf-ofb             Blowfish in OFB mode
 289
 290  cast-cbc           CAST in CBC mode
 291  cast               Alias for cast-cbc
 292  cast5-cbc          CAST5 in CBC mode
 293  cast5-cfb          CAST5 in CFB mode
 294  cast5-ecb          CAST5 in ECB mode
 295  cast5-ofb          CAST5 in OFB mode
 296
 297  chacha20           ChaCha20 algorithm
 298
 299  des-cbc            DES in CBC mode
 300  des                Alias for des-cbc
 301  des-cfb            DES in CFB mode
 302  des-ofb            DES in OFB mode
 303  des-ecb            DES in ECB mode
 304
 305  des-ede-cbc        Two key triple DES EDE in CBC mode
 306  des-ede            Two key triple DES EDE in ECB mode
 307  des-ede-cfb        Two key triple DES EDE in CFB mode
 308  des-ede-ofb        Two key triple DES EDE in OFB mode
 309
 310  des-ede3-cbc       Three key triple DES EDE in CBC mode
 311  des-ede3           Three key triple DES EDE in ECB mode
 312  des3               Alias for des-ede3-cbc
 313  des-ede3-cfb       Three key triple DES EDE CFB mode
 314  des-ede3-ofb       Three key triple DES EDE in OFB mode
 315
 316  desx               DESX algorithm.
 317
 318  gost89             GOST 28147-89 in CFB mode (provided by ccgost engine)
 319  gost89-cnt        `GOST 28147-89 in CNT mode (provided by ccgost engine)
 320
 321  idea-cbc           IDEA algorithm in CBC mode
 322  idea               same as idea-cbc
 323  idea-cfb           IDEA in CFB mode
 324  idea-ecb           IDEA in ECB mode
 325  idea-ofb           IDEA in OFB mode
 326
 327  rc2-cbc            128 bit RC2 in CBC mode
 328  rc2                Alias for rc2-cbc
 329  rc2-cfb            128 bit RC2 in CFB mode
 330  rc2-ecb            128 bit RC2 in ECB mode
 331  rc2-ofb            128 bit RC2 in OFB mode
 332  rc2-64-cbc         64 bit RC2 in CBC mode
 333  rc2-40-cbc         40 bit RC2 in CBC mode
 334
 335  rc4                128 bit RC4
 336  rc4-64             64 bit RC4
 337  rc4-40             40 bit RC4
 338
 339  rc5-cbc            RC5 cipher in CBC mode
 340  rc5                Alias for rc5-cbc
 341  rc5-cfb            RC5 cipher in CFB mode
 342  rc5-ecb            RC5 cipher in ECB mode
 343  rc5-ofb            RC5 cipher in OFB mode
 344
 345  seed-cbc           SEED cipher in CBC mode
 346  seed               Alias for seed-cbc
 347  seed-cfb           SEED cipher in CFB mode
 348  seed-ecb           SEED cipher in ECB mode
 349  seed-ofb           SEED cipher in OFB mode
 350
 351  sm4-cbc            SM4 cipher in CBC mode
 352  sm4                Alias for sm4-cbc
 353  sm4-cfb            SM4 cipher in CFB mode
 354  sm4-ctr            SM4 cipher in CTR mode
 355  sm4-ecb            SM4 cipher in ECB mode
 356  sm4-ofb            SM4 cipher in OFB mode
 357
 358  aes-[128|192|256]-cbc  128/192/256 bit AES in CBC mode
 359  aes[128|192|256]       Alias for aes-[128|192|256]-cbc
 360  aes-[128|192|256]-cfb  128/192/256 bit AES in 128 bit CFB mode
 361  aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode
 362  aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode
 363  aes-[128|192|256]-ctr  128/192/256 bit AES in CTR mode
 364  aes-[128|192|256]-ecb  128/192/256 bit AES in ECB mode
 365  aes-[128|192|256]-ofb  128/192/256 bit AES in OFB mode
 366
 367  aria-[128|192|256]-cbc  128/192/256 bit ARIA in CBC mode
 368  aria[128|192|256]       Alias for aria-[128|192|256]-cbc
 369  aria-[128|192|256]-cfb  128/192/256 bit ARIA in 128 bit CFB mode
 370  aria-[128|192|256]-cfb1 128/192/256 bit ARIA in 1 bit CFB mode
 371  aria-[128|192|256]-cfb8 128/192/256 bit ARIA in 8 bit CFB mode
 372  aria-[128|192|256]-ctr  128/192/256 bit ARIA in CTR mode
 373  aria-[128|192|256]-ecb  128/192/256 bit ARIA in ECB mode
 374  aria-[128|192|256]-ofb  128/192/256 bit ARIA in OFB mode
 375
 376  camellia-[128|192|256]-cbc  128/192/256 bit Camellia in CBC mode
 377  camellia[128|192|256]       Alias for camellia-[128|192|256]-cbc
 378  camellia-[128|192|256]-cfb  128/192/256 bit Camellia in 128 bit CFB mode
 379  camellia-[128|192|256]-cfb1 128/192/256 bit Camellia in 1 bit CFB mode
 380  camellia-[128|192|256]-cfb8 128/192/256 bit Camellia in 8 bit CFB mode
 381  camellia-[128|192|256]-ctr  128/192/256 bit Camellia in CTR mode
 382  camellia-[128|192|256]-ecb  128/192/256 bit Camellia in ECB mode
 383  camellia-[128|192|256]-ofb  128/192/256 bit Camellia in OFB mode
 384
 385 =head1 EXAMPLES
 386
 387 Just base64 encode a binary file:
 388
 389  openssl base64 -in file.bin -out file.b64
 390
 391 Decode the same file
 392
 393  openssl base64 -d -in file.b64 -out file.bin
 394
 395 Encrypt a file using AES-128 using a prompted password
 396 and PBKDF2 key derivation:
 397
 398  openssl enc -aes128 -pbkdf2 -in file.txt -out file.aes128
 399
 400 Decrypt a file using a supplied password:
 401
 402  openssl enc -aes128 -pbkdf2 -d -in file.aes128 -out file.txt \
 403     -pass pass:<password>
 404
 405 Encrypt a file then base64 encode it (so it can be sent via mail for example)
 406 using AES-256 in CTR mode and PBKDF2 key derivation:
 407
 408  openssl enc -aes-256-ctr -pbkdf2 -a -in file.txt -out file.aes256
 409
 410 Base64 decode a file then decrypt it using a password supplied in a file:
 411
 412  openssl enc -aes-256-ctr -pbkdf2 -d -a -in file.aes256 -out file.txt \
 413     -pass file:<passfile>
 414
 415 =head1 BUGS
 416
 417 The B<-A> option when used with large files doesn't work properly.
 418
 419 The B<openssl enc> command only supports a fixed number of algorithms with
 420 certain parameters. So if, for example, you want to use RC2 with a
 421 76 bit key or RC4 with an 84 bit key you can't use this program.
 422
 423 =head1 HISTORY
 424
 425 The default digest was changed from MD5 to SHA256 in OpenSSL 1.1.0.
 426
 427 The B<-list> option was added in OpenSSL 1.1.1e.
 428
 429 The B<-ciphers> option was deprecated in OpenSSL 3.0.
 430
 431 =head1 COPYRIGHT
 432
 433 Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
 434
 435 Licensed under the Apache License 2.0 (the "License").  You may not use
 436 this file except in compliance with the License.  You can obtain a copy
 437 in the file LICENSE in the source distribution or at
 438 L<https://www.openssl.org/source/license.html>.
 439
 440 =cut