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128 lines
3.8 KiB
128 lines
3.8 KiB
4 years ago
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# 9.6 加密和解密数据
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前面小节介绍了如何存储密码,但是有的时候,我们想把一些敏感数据加密后存储起来,在将来的某个时候,随需将它们解密出来,此时我们应该在选用对称加密算法来满足我们的需求。
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## base64加解密
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如果Web应用足够简单,数据的安全性没有那么严格的要求,那么可以采用一种比较简单的加解密方法是`base64`,这种方式实现起来比较简单,Go语言的`base64`包已经很好的支持了这个,请看下面的例子:
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```Go
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package main
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import (
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"encoding/base64"
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"fmt"
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)
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func base64Encode(src []byte) []byte {
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return []byte(base64.StdEncoding.EncodeToString(src))
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}
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func base64Decode(src []byte) ([]byte, error) {
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return base64.StdEncoding.DecodeString(string(src))
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}
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func main() {
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// encode
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hello := "你好,世界! hello world"
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debyte := base64Encode([]byte(hello))
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fmt.Println(debyte)
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// decode
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enbyte, err := base64Decode(debyte)
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if err != nil {
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fmt.Println(err.Error())
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}
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if hello != string(enbyte) {
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fmt.Println("hello is not equal to enbyte")
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}
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fmt.Println(string(enbyte))
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}
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```
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## 高级加解密
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Go语言的`crypto`里面支持对称加密的高级加解密包有:
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- `crypto/aes`包:AES(Advanced Encryption Standard),又称Rijndael加密法,是美国联邦政府采用的一种区块加密标准。
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- `crypto/des`包:DES(Data Encryption Standard),是一种对称加密标准,是目前使用最广泛的密钥系统,特别是在保护金融数据的安全中。曾是美国联邦政府的加密标准,但现已被AES所替代。
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因为这两种算法使用方法类似,所以在此,我们仅用aes包为例来讲解它们的使用,请看下面的例子
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```Go
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package main
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import (
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"crypto/aes"
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"crypto/cipher"
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"fmt"
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"os"
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)
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var commonIV = []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f}
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func main() {
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//需要去加密的字符串
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plaintext := []byte("My name is Astaxie")
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//如果传入加密串的话,plaint就是传入的字符串
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if len(os.Args) > 1 {
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plaintext = []byte(os.Args[1])
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}
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//aes的加密字符串
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key_text := "astaxie12798akljzmknm.ahkjkljl;k"
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if len(os.Args) > 2 {
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key_text = os.Args[2]
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}
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fmt.Println(len(key_text))
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// 创建加密算法aes
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c, err := aes.NewCipher([]byte(key_text))
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if err != nil {
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fmt.Printf("Error: NewCipher(%d bytes) = %s", len(key_text), err)
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os.Exit(-1)
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}
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//加密字符串
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cfb := cipher.NewCFBEncrypter(c, commonIV)
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ciphertext := make([]byte, len(plaintext))
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cfb.XORKeyStream(ciphertext, plaintext)
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fmt.Printf("%s=>%x\n", plaintext, ciphertext)
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// 解密字符串
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cfbdec := cipher.NewCFBDecrypter(c, commonIV)
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plaintextCopy := make([]byte, len(plaintext))
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cfbdec.XORKeyStream(plaintextCopy, ciphertext)
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fmt.Printf("%x=>%s\n", ciphertext, plaintextCopy)
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}
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```
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上面通过调用函数`aes.NewCipher`(参数key必须是16、24或者32位的[]byte,分别对应AES-128, AES-192或AES-256算法),返回了一个`cipher.Block`接口,这个接口实现了三个功能:
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```Go
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type Block interface {
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// BlockSize returns the cipher's block size.
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BlockSize() int
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// Encrypt encrypts the first block in src into dst.
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// Dst and src may point at the same memory.
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Encrypt(dst, src []byte)
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// Decrypt decrypts the first block in src into dst.
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// Dst and src may point at the same memory.
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Decrypt(dst, src []byte)
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}
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```
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这三个函数实现了加解密操作,详细的操作请看上面的例子。
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## 总结
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这小节介绍了几种加解密的算法,在开发Web应用的时候可以根据需求采用不同的方式进行加解密,一般的应用可以采用base64算法,更加高级的话可以采用aes或者des算法。
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## links
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* [目录](<preface.md>)
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* 上一节: [存储密码](<09.5.md>)
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* 下一节: [小结](<09.7.md>)
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