Provided by: openssl_3.0.5-2ubuntu1_amd64 bug

NAME

       openssl-enc - symmetric cipher routines

SYNOPSIS

       openssl enc|cipher [-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] [-v] [-debug] [-none] [-engine id] [-rand files] [-writerand
       file] [-provider name] [-provider-path path] [-propquery propq]

       openssl cipher [...]

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

       -cipher
           The cipher to use.

       -help
           Print out a usage message.

       -list
           List all supported ciphers.

       -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
           openssl-passphrase-options(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.

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 Superseded by the -pass argument.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 Superseded by the -pass argument.

       -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.

       -pbkdf2
           Use PBKDF2 algorithm with default iteration count unless otherwise specified.

       -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.

       -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.  If this
           option is used while encrypting, the same exact value will be needed again during
           decryption.

       -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.

       -nopad
           Disable standard block padding.

       -v  Verbose print; display some statistics about I/O and buffer sizes.

       -debug
           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.

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

       -rand files, -writerand file
           See "Random State Options" in openssl(1) for details.

       -provider name
       -provider-path path
       -propquery propq
           See "Provider Options" in openssl(1), provider(7), and property(7).

       -engine id
           See "Engine Options" in openssl(1).  This option is deprecated.

NOTES

       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 openssl-list(1) 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 option 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 OpenSSL.

       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 generated at random (that means when encrypting using a passphrase
       without explicit salt given using -S option), the first bytes of the encrypted data are
       reserved to store the salt for later decrypting.

       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.

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 when
       invoking this command with the -list option (that is "openssl enc -list") is a list of
       ciphers, supported by your version of OpenSSL, including ones provided by configured
       engines.

       This command does not support authenticated encryption modes like CCM and GCM, and will
       not support such modes in the future.  This is due to having to begin streaming output
       (e.g., to standard output when -out is not used) before the authentication tag could be
       validated.  When this command is used in a pipeline, the receiving end will not be able to
       roll 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 openssl 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 this command, 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, openssl-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

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 AES-128 using a prompted password and PBKDF2 key derivation:

        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 file:

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

BUGS

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

       The openssl enc command 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.

HISTORY

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

       The -list option was added in OpenSSL 1.1.1e.

       The -ciphers and -engine options were deprecated in OpenSSL 3.0.

COPYRIGHT

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

       Licensed under the Apache License 2.0 (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 <https://www.openssl.org/source/license.html>.