enc.pod 14 KB

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 Superseded by the B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