perf: 优化Shiro.go的代码，添加注释，规范输出

WebScan/lib/Shiro.go

@@ -12,62 +12,91 @@ import (
 )
 
 var (
+	// CheckContent 是经过base64编码的Shiro序列化对象
 	CheckContent = "rO0ABXNyADJvcmcuYXBhY2hlLnNoaXJvLnN1YmplY3QuU2ltcGxlUHJpbmNpcGFsQ29sbGVjdGlvbqh/WCXGowhKAwABTAAPcmVhbG1QcmluY2lwYWxzdAAPTGphdmEvdXRpbC9NYXA7eHBwdwEAeA=="
-	Content, _   = base64.StdEncoding.DecodeString(CheckContent)
+	// Content 是解码后的原始内容
+	Content, _ = base64.StdEncoding.DecodeString(CheckContent)
 )
 
+// Padding 对明文进行PKCS7填充
 func Padding(plainText []byte, blockSize int) []byte {
-	//计算要填充的长度
-	n := (blockSize - len(plainText)%blockSize)
-	//对原来的明文填充n个n
-	temp := bytes.Repeat([]byte{byte(n)}, n)
-	plainText = append(plainText, temp...)
-	return plainText
+	// 计算需要填充的长度
+	paddingLength := blockSize - len(plainText)%blockSize
+
+	// 使用paddingLength个paddingLength值进行填充
+	paddingText := bytes.Repeat([]byte{byte(paddingLength)}, paddingLength)
+
+	return append(plainText, paddingText...)
 }
 
+// GetShrioCookie 获取加密后的Shiro Cookie值
 func GetShrioCookie(key, mode string) string {
 	if mode == "gcm" {
 		return AES_GCM_Encrypt(key)
-	} else {
-		//cbc
-		return AES_CBC_Encrypt(key)
 	}
+	return AES_CBC_Encrypt(key)
 }
 
-//AES CBC加密后的payload
+// AES_CBC_Encrypt 使用AES-CBC模式加密
 func AES_CBC_Encrypt(shirokey string) string {
+	// 解码密钥
 	key, err := base64.StdEncoding.DecodeString(shirokey)
 	if err != nil {
 		return ""
 	}
+
+	// 创建AES加密器
 	block, err := aes.NewCipher(key)
 	if err != nil {
 		return ""
 	}
-	Content = Padding(Content, block.BlockSize())
-	iv := uuid.NewV4().Bytes()                     //指定初始向量vi,长度和block的块尺寸一致
-	blockMode := cipher.NewCBCEncrypter(block, iv) //指定CBC分组模式，返回一个BlockMode接口对象
-	cipherText := make([]byte, len(Content))
-	blockMode.CryptBlocks(cipherText, Content) //加密数据
-	return base64.StdEncoding.EncodeToString(append(iv[:], cipherText[:]...))
+
+	// PKCS7填充
+	paddedContent := Padding(Content, block.BlockSize())
+
+	// 生成随机IV
+	iv := uuid.NewV4().Bytes()
+
+	// 创建CBC加密器
+	blockMode := cipher.NewCBCEncrypter(block, iv)
+
+	// 加密数据
+	cipherText := make([]byte, len(paddedContent))
+	blockMode.CryptBlocks(cipherText, paddedContent)
+
+	// 拼接IV和密文并base64编码
+	return base64.StdEncoding.EncodeToString(append(iv, cipherText...))
 }
 
-//AES GCM 加密后的payload shiro 1.4.2版本更换为了AES-GCM加密方式
+// AES_GCM_Encrypt 使用AES-GCM模式加密(Shiro 1.4.2+)
 func AES_GCM_Encrypt(shirokey string) string {
+	// 解码密钥
 	key, err := base64.StdEncoding.DecodeString(shirokey)
 	if err != nil {
 		return ""
 	}
+
+	// 创建AES加密器
 	block, err := aes.NewCipher(key)
 	if err != nil {
 		return ""
 	}
+
+	// 生成16字节随机数作为nonce
 	nonce := make([]byte, 16)
-	_, err = io.ReadFull(rand.Reader, nonce)
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return ""
+	}
+
+	// 创建GCM加密器
+	aesgcm, err := cipher.NewGCMWithNonceSize(block, 16)
 	if err != nil {
 		return ""
 	}
-	aesgcm, _ := cipher.NewGCMWithNonceSize(block, 16)
+
+	// 加密数据
 	ciphertext := aesgcm.Seal(nil, nonce, Content, nil)
+
+	// 拼接nonce和密文并base64编码
 	return base64.StdEncoding.EncodeToString(append(nonce, ciphertext...))
 }