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ENC(1)				    OpenSSL				ENC(1)

       openssl-enc, enc	- symmetric cipher routines

       openssl enc -cipher [-help] [-list] [-ciphers] [-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 digest] [-iter count] [-pbkdf2] [-p] [-P] [-bufsize	number]
       [-nopad]	[-debug] [-none] [-rand	file...]  [-writerand file] [-engine

       openssl [cipher]	[...]

       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.

	   Print out a usage message.

	   List	all supported ciphers.

	   Alias of -list to display all supported ciphers.

       -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 "Pass Phrase Options" in	openssl(1).

       -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.

	   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 Superseded by the -pass argument.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 Superseded by the -pass argument.

       -md digest
	   Use the specified digest to create the key from the passphrase.
	   The default algorithm is sha-256.

       -iter count
	   Use a given number of iterations on the password in deriving	the
	   encryption key.  High values	increase the time required to brute-
	   force the resulting file.  This option enables the use of PBKDF2
	   algorithm to	derive the key.

	   Use PBKDF2 algorithm	with default iteration count unless otherwise

	   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.

	   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

       -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
	   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.

	   Disable standard block padding.

	   Debug the BIOs used for I/O.

       -z  Compress or decompress encrypted data using zlib after encryption
	   or before decryption. This option exists only if OpenSSL was
	   compiled with the zlib or zlib-dynamic option.

	   Use NULL cipher (no encryption or decryption	of input).

       -rand file...
	   A file or files containing random data used to seed the random
	   number generator.  Multiple files can be specified separated	by an
	   OS-dependent	character.  The	separator is ; for MS-Windows, , for
	   OpenVMS, and	: for all others.

       [-writerand file]
	   Writes random data to the specified file upon exit.	This can be
	   used	with a subsequent -rand	flag.

       The program can be called either	as openssl cipher or openssl enc
       -cipher.	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.	Use the	list command to	get a list of
       supported ciphers.

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

       When the	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

       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, such as AES, in CBC	mode.

       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.

       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 the -ciphers
       option (that is openssl enc -ciphers) produces a	list of	ciphers,
       supported by your version of OpenSSL, including ones provided by
       configured engines.

       The enc program does not	support	authenticated encryption modes like
       CCM and GCM, and	will not support such modes in the future.  The	enc
       interface by necessity must begin streaming output (e.g., to standard
       output when -out	is not used) before the	authentication tag could be
       validated, leading to the usage of enc in pipelines that	begin
       processing untrusted data and are not capable of	rolling	back upon
       authentication failure.	The AEAD modes currently in common use also
       suffer from catastrophic	failure	of confidentiality and/or integrity
       upon reuse of key/iv/nonce, and since enc places	the entire burden of
       key/iv/nonce management upon the	user, the risk of exposing AEAD	modes
       is too great to allow.  These key/iv/nonce management issues also
       affect other modes currently exposed in enc, but	the failure modes are
       less extreme in these cases, and	the functionality cannot be removed
       with a stable release branch.  For bulk encryption of data, whether
       using authenticated encryption modes or other modes, cms(1) is
       recommended, as it provides a standard data format and performs the
       needed key/iv/nonce management.

	base64		   Base	64

	bf-cbc		   Blowfish in CBC mode
	bf		   Alias for bf-cbc
	blowfish	   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

	chacha20	   ChaCha20 algorithm

	des-cbc		   DES in CBC mode
	des		   Alias for des-cbc
	des-cfb		   DES in CFB 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

	seed-cbc	   SEED	cipher in CBC mode
	seed		   Alias for seed-cbc
	seed-cfb	   SEED	cipher in CFB mode
	seed-ecb	   SEED	cipher in ECB mode
	seed-ofb	   SEED	cipher in OFB mode

	sm4-cbc		   SM4 cipher in CBC mode
	sm4		   Alias for sm4-cbc
	sm4-cfb		   SM4 cipher in CFB mode
	sm4-ctr		   SM4 cipher in CTR mode
	sm4-ecb		   SM4 cipher in ECB mode
	sm4-ofb		   SM4 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]-ctr  128/192/256 bit AES in CTR 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

	aria-[128|192|256]-cbc	128/192/256 bit	ARIA in	CBC mode
	aria[128|192|256]	Alias for aria-[128|192|256]-cbc
	aria-[128|192|256]-cfb	128/192/256 bit	ARIA in	128 bit	CFB mode
	aria-[128|192|256]-cfb1	128/192/256 bit	ARIA in	1 bit CFB mode
	aria-[128|192|256]-cfb8	128/192/256 bit	ARIA in	8 bit CFB mode
	aria-[128|192|256]-ctr	128/192/256 bit	ARIA in	CTR mode
	aria-[128|192|256]-ecb	128/192/256 bit	ARIA in	ECB mode
	aria-[128|192|256]-ofb	128/192/256 bit	ARIA in	OFB mode

	camellia-[128|192|256]-cbc  128/192/256	bit Camellia in	CBC mode
	camellia[128|192|256]	    Alias for camellia-[128|192|256]-cbc
	camellia-[128|192|256]-cfb  128/192/256	bit Camellia in	128 bit	CFB mode
	camellia-[128|192|256]-cfb1 128/192/256	bit Camellia in	1 bit CFB mode
	camellia-[128|192|256]-cfb8 128/192/256	bit Camellia in	8 bit CFB mode
	camellia-[128|192|256]-ctr  128/192/256	bit Camellia in	CTR mode
	camellia-[128|192|256]-ecb  128/192/256	bit Camellia in	ECB mode
	camellia-[128|192|256]-ofb  128/192/256	bit Camellia in	OFB mode

       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 AES-128 using a prompted password and PBKDF2 key

	openssl	enc -aes128 -pbkdf2 -in	file.txt -out file.aes128

       Decrypt a file using a supplied password:

	openssl	enc -aes128 -pbkdf2 -d -in file.aes128 -out file.txt \
	   -pass pass:<password>

       Encrypt a file then base64 encode it (so	it can be sent via mail	for
       example)	using AES-256 in CTR mode and PBKDF2 key derivation:

	openssl	enc -aes-256-ctr -pbkdf2 -a -in	file.txt -out file.aes256

       Base64 decode a file then decrypt it using a password supplied in a

	openssl	enc -aes-256-ctr -pbkdf2 -d -a -in file.aes256 -out file.txt \
	   -pass file:<passfile>

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

       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.

       The default digest was changed from MD5 to SHA256 in OpenSSL 1.1.0.

       The -list option	was added in OpenSSL 1.1.1e.

       Copyright 2000-2021 The OpenSSL Project Authors.	All Rights Reserved.

       Licensed	under the OpenSSL license (the "License").  You	may not	use
       this file except	in compliance with the License.	 You can obtain	a copy
       in the file LICENSE in the source distribution or at

1.1.1o				  2022-05-03				ENC(1)


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