一、简介
enc - 对称加密例程，使用对称密钥对数据进行加解密，特点是速度快，能对大量数据进行处理。算法有流算法和分组加密算法，流算法是逐字节加，由于其容易被破译，现在已很少使用；分组加密算法是将数据分成固定大小的组里，然后逐组进行加密，如DES。分组算法中又有ECB，CBC,CFB,OFB,CTR等工作模式，其中默认选CBC工作模式。
二、语法
openssl enc -ciphername[-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] [-p] [-P] [-bufsize number] [-nopad] [-debug] [-none] [-engine id]
选项
-in <file> input file -out <file> output file -pass <arg> pass phrase source -e encrypt -d decrypt -a/-base64 base64 encode/decode, depending on encryption flag -k passphrase is the next argument -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. See openssl dgst -h for list. -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 <n> buffer size -nopad disable standard block padding -engine e use engine e, possibly a hardware device.
三、实例
1、使用des3算法对文件进行加密，并解密
openssl enc -p -des3 -pass pass:123456 -in test.txt -out cipher.txt
openssl enc -d -des3 -pass pass:123456 -in cipher.txt -out plain.txt
2、加密对数据进行base64编码，并在解密前对数据进行base64解码
openssl enc -p -des3 -a -pass pass:123456 -in test.txt -out cipher.txt openssl enc -d -des3 -a -pass pass:123456 -in cipher.txt -out plain.txt
