字段加密后长度变化

 非对称加密算法：RSA，DSA/DSS 
 对称加密算法：AES，RC4，3DES 
 HASH算法：MD5，SHA1，SHA256

func getCount(text string) int {
 l := countBytes(text)
 l = countPadding(l)
 l = countEncrypt(l, true)
 l = countBase64(l)
 return l
}

func countBytes(text string) int {
 orig := []byte(text)
 return len(orig)
}

func countPadding(l int) int {
 pl := 16 - (l % 16)
 return l + pl
}

func countEncrypt(l int, flag bool) int {
 if flag == false {
  return l + 16
 }
 return l + 16 + 12
}

func countBase64(l int) int {
 if l%3 == 0 {
  return l / 3 * 4
 } else {
  return (l/3 + 1) * 4
 }
}