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ENC(1)				    OpenSSL				ENC(1)

NAME
       enc - symmetric cipher routines

SYNOPSIS
       openssl enc -ciphername [-in filename] [-out filename] [-pass arg] [-e]
       [-d] [-a/-base64] [-A] [-k password] [-kfile filename] [-K key] [-iv
       IV] [-S salt] [-salt] [-nosalt] [-z] [-md] [-p] [-P] [-bufsize number]
       [-nopad]	[-debug] [-none] [-engine id]

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.

OPTIONS
       -in filename
	   the input filename, standard	input by default.

       -out filename
	   the output filename,	standard output	by default.

       -pass arg
	   the password	source.	For more information about the format of arg
	   see the PASS	PHRASE ARGUMENTS section in openssl(1).

       -salt
	   use a salt in the key derivation routines. This is the default.

       -nosalt
	   don't use a salt in the key derivation routines. This option	SHOULD
	   NOT be used except for test purposes	or compatibility with ancient
	   versions of OpenSSL and SSLeay.

       -e  encrypt the input data: this	is the default.

       -d  decrypt the input data.

       -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.

       -base64
	   same	as -a

       -A  if the -a option is set then	base64 process the data	on one line.

       -k password
	   the password	to derive the key from.	This is	for compatibility with
	   previous versions of	OpenSSL. Superseded by the -pass argument.

       -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 Superseded by the -pass argument.

       -nosalt
	   do not use a	salt

       -salt
	   use salt (randomly generated	or provide with	-S option) when
	   encrypting (this is the default).

       -S salt
	   the actual salt to use: this	must be	represented as a string	of hex
	   digits.

       -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 IV
	   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 IV generated	from the password will be taken. It
	   probably does not make much sense to	specify	both key and password.

       -iv IV
	   the actual IV 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 IV must explicitly be defined. When a password
	   is being specified using one	of the other options, the IV is
	   generated from this password.

       -p  print out the key and IV used.

       -P  print out the key and IV used then immediately exit:	don't do any
	   encryption or decryption.

       -bufsize	number
	   set the buffer size for I/O

       -nopad
	   disable standard block padding

       -debug
	   debug the BIOs used for I/O.

       -z  Compress or decompress clear	text using zlib	before encryption or
	   after decryption. This option exists	only if	OpenSSL	with compiled
	   with	zlib or	zlib-dynamic option.

       -none
	   Use NULL cipher (no encryption or decryption	of input).

NOTES
       The program can be called either	as openssl ciphername or openssl enc
       -ciphername. But	the first form doesn't work with engine-provided
       ciphers,	because	this form is processed before the configuration	file
       is read and any ENGINEs loaded.

       Engines which provide entirely new encryption algorithms	(such as
       ccgost engine which provides gost89 algorithm) should be	configured in
       the configuration file. Engines,	specified in the command line using
       -engine options can only	be used	for hadrware-assisted implementations
       of ciphers, which are supported by OpenSSL core or other	engine,
       specified in the	configuration file.

       When enc	command	lists supported	ciphers, ciphers provided by engines,
       specified in the	configuration files are	listed too.

       A password will be prompted for to derive the key and IV	if necessary.

       The -salt option	should ALWAYS 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 CBC 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 RC2 ciphers have the	same key and effective key length.

       Blowfish	and RC5	algorithms use a 128 bit key.

SUPPORTED CIPHERS
       Note that some of these ciphers can be disabled at compile time and
       some are	available only if an appropriate engine	is configured in the
       configuration file. The output of the enc command run with unsupported
       options (for example openssl enc	-help) includes	a list of ciphers,
       supported by your versesion of OpenSSL, including ones provided by
       configured engines.

       The enc program does not	support	authenticated encryption modes like
       CCM and GCM. The	utility	does not store or retrieve the authentication
       tag.

	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.

	gost89		   GOST	28147-89 in CFB	mode (provided by ccgost engine)
	gost89-cnt	  `GOST	28147-89 in CNT	mode (provided by ccgost engine)

	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

EXAMPLES
       Just base64 encode a binary file:

	openssl	base64 -in file.bin -out file.b64

       Decode the same file

	openssl	base64 -d -in file.b64 -out file.bin

       Encrypt a file using triple DES in CBC mode using a prompted password:

	openssl	des3 -salt -in file.txt	-out file.des3

       Decrypt a file using a supplied password:

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

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

	openssl	bf -a -salt -in	file.txt -out file.bf

       Base64 decode a file then decrypt it:

	openssl	bf -d -salt -a -in file.bf -out	file.txt

       Decrypt some data using a supplied 40 bit RC4 key:

	openssl	rc4-40 -in file.rc4 -out file.txt -K 0102030405

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 RC2 with	a 76 bit key
       or RC4 with an 84 bit key you can't use this program.

1.0.1i				  2014-08-06				ENC(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | SUPPORTED CIPHERS | EXAMPLES | BUGS

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