Go 语言国密 SM4 加密和解密的实现

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Go 语言国密 SM4 加密和解密的实现

// SM4Encrypt SM4 加密
func SM4Encrypt(origBytes, key []byte) ([]byte, error) {
	block, err := sm4.NewCipher(key)
	if err != nil {
		return nil, err
	}
	blockSize := block.BlockSize()
	origData := pkcs5Padding(origBytes, blockSize)
	iv := make([]byte, sm4.BlockSize)
	blockMode := cipher.NewCBCEncrypter(block, iv)
	encrypted := make([]byte, len(origData))
	blockMode.CryptBlocks(encrypted, origData)
	return encrypted, nil
}

// SM4Decrypt 解密
func SM4Decrypt(encrypted, key []byte) ([]byte, error) {
	block, err := sm4.NewCipher(key)
	if err != nil {
		return nil, err
	}
	iv := make([]byte, sm4.BlockSize)
	blockMode := cipher.NewCBCDecrypter(block, iv)
	origData := make([]byte, len(encrypted))
	blockMode.CryptBlocks(origData, encrypted)
	origData = pkcs5UnPadding(origData)
	return origData, nil
}

// pkcs5Padding pkcs5Padding fill
func pkcs5Padding(src []byte, blockSize int) []byte {
	padding := blockSize - len(src)%blockSize
	padText := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(src, padText...)
}

// pkcs5UnPadding pkcs5UnPadding
func pkcs5UnPadding(src []byte) []byte {
	length := len(src)
	if length == 0 {
		return nil
	}
	unPadding := int(src[length-1])
	return src[length - unPadding)]
}