diff --git a/xy_sh/internal/middleware/middleware.go b/xy_sh/internal/middleware/middleware.go
new file mode 100644
index 0000000..c89b084
--- /dev/null
+++ b/xy_sh/internal/middleware/middleware.go
@@ -0,0 +1,63 @@
+package middleware
+
+import (
+	"encoding/json"
+	"strings"
+
+	"github.com/gofiber/fiber/v2"
+	"xy_sh/internal/config"
+	"xy_sh/pkg/crypto"
+)
+
+// VerifySign 验证签名中间件
+func VerifySign(cfg *config.Config) fiber.Handler {
+	return func(c *fiber.Ctx) error {
+		timestamp := c.Get("timestamp")
+		sign := c.Get("sign")
+
+		if timestamp == "" || sign == "" {
+			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
+				"code": -1,
+				"msg":  "缺少timestamp或sign请求头",
+			})
+		}
+
+		body := c.Body()
+		if len(body) == 0 {
+			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
+				"code": -1,
+				"msg":  "请求体不能为空",
+			})
+		}
+
+		var req struct {
+			EncryptedData string `json:"encryptedData"`
+		}
+		if err := json.Unmarshal(body, &req); err != nil {
+			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
+				"code": -1,
+				"msg":  "请求体格式错误",
+			})
+		}
+
+		// 验证签名：SM3(salt + timestamp + encryptedData)
+		expectedSign := crypto.SM3WithSalt(timestamp+req.EncryptedData, cfg.SM3Salt)
+		if !strings.EqualFold(expectedSign, sign) {
+			return c.Status(fiber.StatusUnauthorized).JSON(fiber.Map{
+				"code": -1,
+				"msg":  "签名验证失败",
+			})
+		}
+
+		decrypted, err := crypto.SM4ECBDecrypt(req.EncryptedData, cfg.SM4Key)
+		if err != nil {
+			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
+				"code": -1,
+				"msg":  "解密失败: " + err.Error(),
+			})
+		}
+
+		c.Locals("decryptedBody", decrypted)
+		return c.Next()
+	}
+}
\ No newline at end of file