initial commit: Go version of SMS Receiver with fixed template rendering

- Implemented all core features from Python version
- Fixed int64/int type compatibility in template functions
- Added login authentication, SMS receiving, statistics, logs
- Independent database: sms_receiver_go.db
- Fixed frontend display issues for message list and statistics

sign/sign.go

@@ -0,0 +1,67 @@
+package sign
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"net/url"
+	"strconv"
+	"time"
+
+	"sms-receiver-go/config"
+)
+
+// GenerateSign 生成签名
+func GenerateSign(timestamp int64, secret string) (string, error) {
+	if secret == "" {
+		return "", nil
+	}
+
+	stringToSign := strconv.FormatInt(timestamp, 10) + "\n" + secret
+
+	hmacCode := hmac.New(sha256.New, []byte(secret))
+	hmacCode.Write([]byte(stringToSign))
+	signBytes := hmacCode.Sum(nil)
+
+	// Base64 编码
+	signBase64 := base64.StdEncoding.EncodeToString(signBytes)
+
+	// URL 编码
+	sign := url.QueryEscape(signBase64)
+
+	return sign, nil
+}
+
+// VerifySign 验证签名
+func VerifySign(token string, timestamp int64, sign string, cfg *config.SecurityConfig) (bool, error) {
+	if !cfg.SignVerify || token == "" {
+		return true, nil
+	}
+
+	// 查找对应的 secret
+	tokenConfig := config.Get().GetTokenByValue(token)
+	if tokenConfig == nil {
+		return false, nil
+	}
+
+	secret := tokenConfig.Secret
+	if secret == "" {
+		// 无 secret，跳过签名验证
+		return true, nil
+	}
+
+	// 检查时间戳是否过期
+	currentTime := time.Now().UnixMilli()
+	if currentTime-timestamp > cfg.SignMaxAge {
+		return false, nil // 时间戳过期
+	}
+
+	// 重新生成签名进行比较
+	expectedSign, err := GenerateSign(timestamp, secret)
+	if err != nil {
+		return false, err
+	}
+
+	// 比较签名
+	return sign == expectedSign, nil
+}