107 lines
2.6 KiB
Go
107 lines
2.6 KiB
Go
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package security
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"errors"
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)
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// AESCipher one of Encryptor implement
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type AESCipher struct {
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key []byte
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iv []byte
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}
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// NewAESCipher return a AESCipher
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func NewAESCipher(key string) *AESCipher {
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size := len(key) / 8
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if size < 2 {
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//log.Error("incorrect key, need 16(aes-128), 24(aes-192), 32(aes-256) length string")
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return nil
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} else if size > 4 {
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size = 4
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}
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key = key[:size*8]
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return &AESCipher{key: []byte(key), iv: []byte(key[:16])}
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}
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// Decode src
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func (cipher *AESCipher) Decode(src []byte) []byte {
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encrypt, err := aesDeCrypt(src, cipher.key, cipher.iv)
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if err != nil {
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return src
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}
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return encrypt
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}
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// Encode src
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func (cipher *AESCipher) Encode(src []byte) []byte {
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encrypt, err := aesEcrypt(src, cipher.key, cipher.iv)
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if err != nil {
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//log.Error("Aes Encode error %s", err)
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return src
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}
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return encrypt
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}
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//PKCS7 填充模式
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func pKCS7Padding(ciphertext []byte, blockSize int) []byte {
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padding := blockSize - len(ciphertext)%blockSize
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//Repeat()函数的功能是把切片[]byte{byte(padding)}复制padding个，然后合并成新的字节切片返回
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padText := bytes.Repeat([]byte{byte(padding)}, padding)
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return append(ciphertext, padText...)
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}
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//填充的反向操作，删除填充字符串
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func pKCS7UnPadding(origData []byte) ([]byte, error) {
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//获取数据长度
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length := len(origData)
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if length == 0 {
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return nil, errors.New("pKCS7UnPadding error")
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}
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//获取填充字符串长度
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unpadding := int(origData[length-1])
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//截取切片，删除填充字节，并且返回明文
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return origData[:(length - unpadding)], nil
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}
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//实现加密
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func aesEcrypt(origData []byte, key, iv []byte) ([]byte, error) {
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//创建加密算法实例
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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//获取块的大小
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blockSize := block.BlockSize()
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//对数据进行填充，让数据长度满足需求
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origData = pKCS7Padding(origData, blockSize)
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//采用AES加密方法中CBC加密模式
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blocMode := cipher.NewCBCEncrypter(block, iv)
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crypted := make([]byte, len(origData))
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//执行加密
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blocMode.CryptBlocks(crypted, origData)
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return crypted, nil
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}
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//实现解密
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func aesDeCrypt(cypted []byte, key, iv []byte) ([]byte, error) {
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//创建加密算法实例
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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//创建加密客户端实例
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blockMode := cipher.NewCBCDecrypter(block, iv)
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origData := make([]byte, len(cypted))
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//这个函数也可以用来解密
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blockMode.CryptBlocks(origData, cypted)
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//去除填充字符串
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origData, err = pKCS7UnPadding(origData)
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if err != nil {
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return nil, err
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}
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return origData, err
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}
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