package main

import (
    "crypto/aes"
    "crypto/cipher"
    "fmt"
)

type tobytes struct {
    cip     cipher.Block
    pdgtext []byte
}

func main() {
    cip,_ := aes.NewCipher([]byte("1234567891234567"))
    enc := &tobytes{cip: cip,pdgtext: make([]byte,cip.BlockSize())}
    src := enc.Encrypt([]byte("czxichen"))
    dst := enc.Decrypt(src)
    fmt.Println(string(dst))
}
 //使用AES加密文本,加密的文本不能为空
func (a *tobytes) Encrypt(src []byte) (dst []byte) {
    src = a.padding(src)
    dst = make([]byte,len(src))
    var index int = 0
    for len(src) > 0 {
        a.cip.Encrypt(dst[index:index+a.cip.BlockSize()],src)
        index += a.cip.BlockSize()
        src = src[a.cip.BlockSize():]
    }
    return dst
}
 //使用AES解密文本
func (a *tobytes) Decrypt(src []byte) (dst []byte) {
    if len(src)%a.cip.BlockSize() != 0 {
        return src
    }
    dst = make([]byte,len(src))
    var index int = 0
    for len(src) > 0 {
        a.cip.Decrypt(dst[index:index+a.cip.BlockSize()],src)
        index += a.cip.BlockSize()
        src = src[a.cip.BlockSize():]
    }
    return a.unpadding(dst)
}
 //使用AES加密文本的时候文本必须定长,即必须是16,24,32的整数倍,
func (a *tobytes) padding(src []byte) (dst []byte) {
    pdg := a.cip.BlockSize() - len(src)%a.cip.BlockSize()
    p := a.pdgtext[:pdg]
    p[pdg-1] = byte(pdg)
    return append(src,p...)
}
 //使用AES解密文本,解密收删除padding的文本
func (a *tobytes) unpadding(src []byte) (dst []byte) {
    length := len(src)
    if length <= 0 {
        return src
    }
    return src[:(length - int(src[length-1]))]
}