shc介绍
shc是shell编译器(Shell Compiler)的缩写， 它可以对shell脚本进行编译和加密。它能够将shell脚本编译为可执行的二进制文件，其中包含了脚本的功能和逻辑，而不暴露源代码。可以说shc就是一个加密shell脚本的工具。shc的官方网址为：http://www.datsi.fi.upm.es/~frosal/sources/。shc在github上没有对应的链接。其实也能理解，不是每一个人都喜欢将自己的项目上传到github上。
官方文档关于shc的描述说明如下：
shc creates a stripped binary executable version of the script specified with -f on the command line. The binary version will get a .x extension appended and will usually be a bit larger in size than the original ascii code. Generated C source code is saved in a file with the extension .x.c If you supply an expiration date with the -e option the com- piled binary will refuse to run after the date specified. The message "Please contact your provider" will be displayed instead. This message can be changed with the -m option. You can compile any kind of shell script, but you need to supply valid -i, -x and -l options. The compiled binary will still be dependent on the shell specified in the first line of the shell code (i.e. #!/bin/sh), thus shc does not create completely independent binaries. shc itself is not a compiler such as cc, it rather encodes and encrypts a shell script and generates C source code with the added expiration capability. It then uses the system compiler to compile a stripped binary which behaves exactly like the original script. Upon execution, the compiled binary will decrypt and execute the code with the shell -c option. Unfortunatelly, it will not give you any speed improvement as a real C program would. shc's main purpose is to protect your shell scripts from modification or inspection. You can use it if you wish to distribute your scripts but don't want them to be easily readable by other people.
shc安装
sqc的安装有多种方式，可以根据适合自己的方式来安装，因为各自环境不一样，可能选择的安装方式不一样。
yum安装
# yum -y install shc
不过有些Linux版本的yum源可能没有shc包，所以这种方式只适用yum源有shc包的环境。
离线安装
根据对应的Linux发行版本，从https://pkgs.org/ 搜索shc对应平台的rpm包，如下所示，当前测试环境的rpm包下载地址[1]
# yum install -y shc-4.0.3-1.el8.x86_64.rpms
源码安装
源码下载地址http://www.datsi.fi.upm.es/~frosal/sources/
mkdir /usr/local/manmkdir /usr/local/man/man1 #install时会把man文件放入该目录。tar vxf shc-3.8.9.tgz && cd shc-3.8.9make testmake stringsmake install
shc使用
下面是shc比较常用的参数说明，更多参数说明请参考man手册或官方文档。
参数
参数说明
-h
显示帮助信息并退出
-f
指定需要加密的shell脚本
-v
参数-v表示verbose模式，输出更详细的编译日志
-r
可以在相同操作系统的不同系统中执行，也就是放宽安全限制，生成可再分发的二进制文件
-o
输出文件名，也可以不指定
-f
指定shell脚本名称
-e
指定过期日期
-m
指定过期后的提示信息
-U
使二进制无法被追踪，默认不开启
-H
强化：额外的安全保护,默认不开启,它需要shell不支持参数
加密shell脚本的例子
# shc -v -f monitor_long_trx.shshc shll=bashshc [-i]=-cshc [-x]=exec '%s' "$@"shc [-l]=shc opts=shc: cc monitor_long_trx.sh.x.c -o monitor_long_trx.sh.xshc: strip monitor_long_trx.sh.xshc: chmod ug=rwx,o=rx monitor_long_trx.sh.x
如下所示，脚本执行后生成了两个文件，其中monitor_long_trx.sh.x是加密过后的可执行的二进制文件。monitor_long_trx.sh.x.c是生成monitor_long_trx.sh.x的原文件(C语言)，也就是说编译这个C源代码文件可以创建上面加密的monitor_long_trx.sh.x文件。
# ls -lrt monitor_long_trx*-rw-r--r-- 1 root root 10185 Sep 27 15:51 monitor_long_trx.sh-rw-r--r-- 1 root root 70193 Sep 29 22:16 monitor_long_trx.sh.x.c-rwxrwxr-x 1 root root 24584 Sep 29 22:16 monitor_long_trx.sh.x# file monitor_long_trx.sh.xmonitor_long_trx.sh.x: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=906ccbd32b4e0fa3307be46ff7736bbfac9be25c, stripped# file monitor_long_trx.sh.x.cmonitor_long_trx.sh.x.c: ASCII text
不过这个C源代码文件，跟你想象的C语言源代码文件可能有点不一样。如下所示，
shc还提供了一种设定有效执行期限的方法，编译生成的可执行二进制文件在过了这个有效性后，就不能执行。
shc -e 09/20/2024 -v -f monitor_long_trx.sh或shc -e 09/20/2024 -v -m "the script has expired, please contact your provierder xxx@xxx.com" -f monitor_long_trx.sh
# shc -e 09/20/2024 -v -f monitor_long_trx.shshc shll=bashshc [-i]=-cshc [-x]=exec '%s' "$@"shc [-l]=shc opts=shc: cc monitor_long_trx.sh.x.c -o monitor_long_trx.sh.xshc: strip monitor_long_trx.sh.xshc: chmod ug=rwx,o=rx monitor_long_trx.sh.x
一些简单常用的例子
shc -f monitor_long_trx.shshc -v -r -f monitor_long_trx.sh -o mon_long_trx.shshc -v -r -u -H -f monitor_long_trx.sh -o mon_long_trx.shshc -v -r -e 09/20/2025 -m "the script has expired..." -f monitor_long_trx.sh -o mon_long_trx.sh
shc评测
shc编译出来的二进制可执行文件，可能比原shell脚本在文件大小上稍微大上一些，相比gzexe和Bashfuscator等工具，它要可靠很多(Bashfuscator就非常不可靠，有些混淆出来的脚本执行会报错)。从个人简单的测试和实践来看，这个工具非常好用，而且用途非常广泛。
那么shc加密过后的可执行二进制文件，能否被解密呢？ 答案是低版本sqc生成的加密二进制可执行文件可以被解密，可以被工具UnSHc[2]解密。而高版本shc(4.x)生成加密文件越来越难解密(暂时不能解密，不代表不能被后续的工具或方法解密)。
下面是UnSHc中的介绍说明，有兴趣可以看看了解一下
Due to the many problems since shc 4.0.3, there seems to be a need for clarification. In shc 4.0.3 many structural changes have been incorporated, so that shc now makes use of various security mechanisms provided by the linux-kernel itself. Therefore, it is now almost impossible to extract the original shell script at all with current UnSHc version, if the new shc version was used. This requires a more in-depth approach, which means that a modified bash or a modified linux-kernel is needed to bypass the security measures.
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参考资料
[1] 1: https://dl.fedoraproject.org/pub/epel/8/Everything/x86_64/Packages/s/shc-4.0.3-1.el8.x86_64.rpm
[2] 2: https://github.com/yanncam/UnSHc/