openssl加密文件

openssl是个密码工具集，提供多端接口调用方式
组成:

1. 代码库 libcryto ,libssl(ssl/tls)
2. 工具集 openssl

对称加密

对称加密主要是用aes，des算法
usage:

-in      input file
-out     output file 加密后的文件存放位置
-pass     pass phrase source
-e             encrypt  指定加密算法
-d             decrypt  指定解密算法
-a/-base64     base64 encode/decode, depending on encryption flag   #使用base64编/解码
-k             passphrase is the next argument   指定密码
-kfile         passphrase is the first line of the file argument
-md            the next argument is the md to use to create a key
                 from a passphrase.  One of md2, md5, sha or sha1
-S             salt in hex is the next argument
-K/-iv         key/iv in hex is the next argument 
-[pP]          print the iv/key (then exit if -P)
-bufsize    buffer size
-nopad         disable standard block padding
-engine e      use engine e, possibly a hardware device.
Cipher Types
-aes-128-cbc               -aes-128-ccm               -aes-128-cfb
...

加密:

cat 123.txt
openssl.exe enc -e -aes-128-cbc -in 123.txt  -k qqqq -out 321.txt

解密:

openssl.exe enc -d -aes-128-cbc -in 321.txt  -k qqqq  -out 456.txt
cat  456.txt