Automatically generated by Pod::Man 2.28 (Pod::Simple 3.28)

Standard preamble:
========================================================================
..

..

.. Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is turned on, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "ENC 1" For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
enc - symmetric cipher routines Header "SYNOPSIS" \fBopenssl enc -ciphername [-in filename] [-out filename] [-pass arg] [-e] [-d] [-a] [-A] [-k password] [-kfile filename] [-K key] [-iv \s-1IV\s0] [-p] [-P] [-bufsize number] [-nopad] [-debug] Header "DESCRIPTION" The symmetric cipher commands allow data to be encrypted or decrypted using various block and stream ciphers using keys based on passwords or explicitly provided. Base64 encoding or decoding can also be performed either by itself or in addition to the encryption or decryption. Header "OPTIONS" Item "-in filename" the input filename, standard input by default. Item "-out filename" the output filename, standard output by default. Item "-pass arg" the password source. For more information about the format of arg see the \s-1PASS PHRASE ARGUMENTS\s0 section in openssl\|(1). Item "-salt" use a salt in the key derivation routines. This is the default. Item "-nosalt" don't use a salt in the key derivation routines. This option \s-1SHOULD NOT\s0 be used except for test purposes or compatibility with ancient versions of OpenSSL and SSLeay. Item "-e" encrypt the input data: this is the default. Item "-d" decrypt the input data. Item "-a" base64 process the data. This means that if encryption is taking place the data is base64 encoded after encryption. If decryption is set then the input data is base64 decoded before being decrypted. Item "-A" if the -a option is set then base64 process the data on one line. Item "-k password" the password to derive the key from. This is for compatibility with previous versions of OpenSSL. Superseded by the -pass argument. Item "-kfile filename" read the password to derive the key from the first line of filename. This is for compatibility with previous versions of OpenSSL. Superseded by the -pass argument. Item "-S salt" the actual salt to use: this must be represented as a string comprised only of hex digits. Item "-K key" the actual key to use: this must be represented as a string comprised only of hex digits. If only the key is specified, the \s-1IV\s0 must additionally specified using the -iv option. When both a key and a password are specified, the key given with the -K option will be used and the \s-1IV\s0 generated from the password will be taken. It probably does not make much sense to specify both key and password. Item "-iv IV" the actual \s-1IV\s0 to use: this must be represented as a string comprised only of hex digits. When only the key is specified using the -K option, the \s-1IV\s0 must explicitly be defined. When a password is being specified using one of the other options, the \s-1IV\s0 is generated from this password. Item "-p" print out the key and \s-1IV\s0 used. Item "-P" print out the key and \s-1IV\s0 used then immediately exit: don't do any encryption or decryption. Item "-bufsize number" set the buffer size for I/O Item "-nopad" disable standard block padding Item "-debug" debug the BIOs used for I/O. Header "NOTES" The program can be called either as openssl ciphername or \fBopenssl enc -ciphername.

A password will be prompted for to derive the key and \s-1IV\s0 if necessary.

The -salt option should \s-1ALWAYS\s0 be used if the key is being derived from a password unless you want compatibility with previous versions of OpenSSL and SSLeay.

Without the -salt option it is possible to perform efficient dictionary attacks on the password and to attack stream cipher encrypted data. The reason for this is that without the salt the same password always generates the same encryption key. When the salt is being used the first eight bytes of the encrypted data are reserved for the salt: it is generated at random when encrypting a file and read from the encrypted file when it is decrypted.

Some of the ciphers do not have large keys and others have security implications if not used correctly. A beginner is advised to just use a strong block cipher in \s-1CBC\s0 mode such as bf or des3.

All the block ciphers normally use PKCS#5 padding also known as standard block padding: this allows a rudimentary integrity or password check to be performed. However since the chance of random data passing the test is better than 1 in 256 it isn't a very good test.

If padding is disabled then the input data must be a multiple of the cipher block length.

All \s-1RC2\s0 ciphers have the same key and effective key length.

Blowfish and \s-1RC5\s0 algorithms use a 128 bit key.

Header "SUPPORTED CIPHERS" .Vb 1 base64 Base 64 \& bf-cbc Blowfish in CBC mode bf Alias for bf-cbc bf-cfb Blowfish in CFB mode bf-ecb Blowfish in ECB mode bf-ofb Blowfish in OFB mode \& cast-cbc CAST in CBC mode cast Alias for cast-cbc cast5-cbc CAST5 in CBC mode cast5-cfb CAST5 in CFB mode cast5-ecb CAST5 in ECB mode cast5-ofb CAST5 in OFB mode \& des-cbc DES in CBC mode des Alias for des-cbc des-cfb DES in CBC mode des-ofb DES in OFB mode des-ecb DES in ECB mode \& des-ede-cbc Two key triple DES EDE in CBC mode des-ede Two key triple DES EDE in ECB mode des-ede-cfb Two key triple DES EDE in CFB mode des-ede-ofb Two key triple DES EDE in OFB mode \& des-ede3-cbc Three key triple DES EDE in CBC mode des-ede3 Three key triple DES EDE in ECB mode des3 Alias for des-ede3-cbc des-ede3-cfb Three key triple DES EDE CFB mode des-ede3-ofb Three key triple DES EDE in OFB mode \& desx DESX algorithm. \& idea-cbc IDEA algorithm in CBC mode idea same as idea-cbc idea-cfb IDEA in CFB mode idea-ecb IDEA in ECB mode idea-ofb IDEA in OFB mode \& rc2-cbc 128 bit RC2 in CBC mode rc2 Alias for rc2-cbc rc2-cfb 128 bit RC2 in CFB mode rc2-ecb 128 bit RC2 in ECB mode rc2-ofb 128 bit RC2 in OFB mode rc2-64-cbc 64 bit RC2 in CBC mode rc2-40-cbc 40 bit RC2 in CBC mode \& rc4 128 bit RC4 rc4-64 64 bit RC4 rc4-40 40 bit RC4 \& rc5-cbc RC5 cipher in CBC mode rc5 Alias for rc5-cbc rc5-cfb RC5 cipher in CFB mode rc5-ecb RC5 cipher in ECB mode rc5-ofb RC5 cipher in OFB mode \& aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode aes-[128|192|256] Alias for aes-[128|192|256]-cbc aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode .Ve Header "EXAMPLES" Just base64 encode a binary file:

.Vb 1 openssl base64 -in file.bin -out file.b64 .Ve

Decode the same file

.Vb 1 openssl base64 -d -in file.b64 -out file.bin .Ve

Encrypt a file using triple \s-1DES\s0 in \s-1CBC\s0 mode using a prompted password:

.Vb 1 openssl des3 -salt -in file.txt -out file.des3 .Ve

Decrypt a file using a supplied password:

.Vb 1 openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword .Ve

Encrypt a file then base64 encode it (so it can be sent via mail for example) using Blowfish in \s-1CBC\s0 mode:

.Vb 1 openssl bf -a -salt -in file.txt -out file.bf .Ve

Base64 decode a file then decrypt it:

.Vb 1 openssl bf -d -salt -a -in file.bf -out file.txt .Ve

Decrypt some data using a supplied 40 bit \s-1RC4\s0 key:

.Vb 1 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405 .Ve

Header "BUGS" The -A option when used with large files doesn't work properly.

There should be an option to allow an iteration count to be included.

The enc program only supports a fixed number of algorithms with certain parameters. So if, for example, you want to use \s-1RC2\s0 with a 76 bit key or \s-1RC4\s0 with an 84 bit key you can't use this program.