GmSSL/doc/apps/enc.pod

=pod

=encoding utf8 

=head1 NAME

enc - symmetric cipher routines

=head1 SYNOPSIS

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

=head1 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.

对称密码命令允许使用基于密码或明确提供的密钥的各种块和流密码来加密或解密数据。 Base64编码或解码也可以通过本身或加密或解密来执行。

=head1 OPTIONS

=over 4

=item B<-help>

Print out a usage message.

输出使用信息

=item B<-ciphers>

List all supported ciphers.

列出所有支持的密码。

=item B<-in filename>

the input filename, standard input by default.

输入的文件名，默认为标准输入。

=item B<-out filename>

the output filename, standard output by default.

输出的文件名，默认为标准输出。

=item B<-pass arg>

the password source. For more information about the format of B<arg>
see the B<PASS PHRASE ARGUMENTS> section in L<gmssl(1)>.

指定密码的来源。

=item B<-e>

encrypt the input data: this is the default.

进行加密操作，默认操作。

=item B<-d>

decrypt the input data.

进行解密操作。

=item B<-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处理数据。这意味着加密结果进行64位编码。解密前先进行base64解码。

=item B<-base64>

same as B<-a>

和-a一样。

=item B<-A>

if the B<-a> option is set then base64 process the data on one line.

将生成的结果在文件中只有一行。

=item B<-k password>

the password to derive the key from. This is for compatibility with previous
versions of GmSSL. Superseded by the B<-pass> argument.

加密口令。这是为了当前GmSSL版本的兼容。

=item B<-kfile filename>

read the password to derive the key from the first line of B<filename>.
This is for compatibility with previous versions of GmSSL. Superseded by
the B<-pass> argument.

指定口令存放的文件。

=item B<-md digest>

Use the specified digest to create the key from the passphrase.
The default algorithm is SM3.

运用指定摘要算法来从密码中创建密钥。默认算法为SM3.

=item B<-nosalt>

don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
used except for test purposes or compatibility with ancient versions of
GmSSL.

在密钥导出例程中不使用salt，除了测试目的或与以前版本的Gmssl兼容，不应使用此选项。

=item B<-salt>

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

在加密过程中使用salt（默认设置）。

=item B<-S salt>

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

salt的值为16进制。

=item B<-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 B<-iv> option. When both a key and a password are specified, the
key given with the B<-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.

用的实际密钥值：这个必须提出，它是一个16进制的输入口令。如果没有这个选
项IV必须用-IV选项指定。当key和密钥都指定时，用-K选项给定的key将会被使
用，而使用密钥来产生初始化向量IV。不建议两者都指定。

=item B<-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 B<-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.

实际上使用的初始化向量：这个必须提出，它是一个16进制的输入口令。如果没有这个选
项IV必须用-IV选项指定。当一个密钥用其中一个选项所指定，IV将会与偶这个口令
值来产生。

=item B<-p>

print out the key and IV used.

打印使用的密钥和IV。

=item B<-P>

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

打印使用的key和IV然后直接退出，不做加密和解密操作。

=item B<-bufsize number>

set the buffer size for I/O

设置I/O操作的缓冲区大小。

=item B<-nopad>

disable standard block padding

没有数据填充。

=item B<-debug>

debug the BIOs used for I/O.

调试用于I/O的BIO。

=item B<-z>

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

在加密或解密之后使用zlib压缩或解压缩明文。 只有使用zlib或zlib-
dynamic选项编译的GmSSL时，此选项才会存在。

=item B<-none>

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

不对数据进行加解密操作。

=back

=head1 NOTES

The program can be called either as B<gmssl ciphername> or
B<gmssl 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 hardware-assisted implementations of
ciphers, which are supported by GmSSL 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 B<-salt> option should B<ALWAYS> be used if the key is being derived
from a password unless you want compatibility with previous versions of
GmSSL.

Without the B<-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.

=head1 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 B<enc> command run with
unsupported options (for example B<gmssl enc -help>) includes a
list of ciphers, supported by your version of GmSSL, including
ones provided by configured engines.

The B<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

=head1 EXAMPLES

Just base64 encode a binary file:

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

Decode the same file

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

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

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

Decrypt a file using a supplied password:

 gmssl 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:

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

Base64 decode a file then decrypt it:

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

Decrypt some data using a supplied 40 bit RC4 key:

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

=head1 BUGS

The B<-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 B<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.

=head1 HISTORY

The default digest was changed from MD5 to SHA256 in Openssl 1.1.

=head1 COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the GmSSL 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
L<https://www.openssl.org/source/license.html>.

=cut