diff --git a/xy_sh/pkg/crypto/crypto.go b/xy_sh/pkg/crypto/crypto.go
new file mode 100644
index 0000000..6c44bef
--- /dev/null
+++ b/xy_sh/pkg/crypto/crypto.go
@@ -0,0 +1,113 @@
+package crypto
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"time"
+
+	"github.com/tjfoc/gmsm/sm3"
+	"github.com/tjfoc/gmsm/sm4"
+)
+
+// ==================== SM3 with Salt ====================
+
+// SM3WithSalt 使用SM3加盐哈希
+// 对应Java hutool的 SmUtil.sm3WithSalt(salt).digestHex(data)
+// hutool实现为：SM3(salt + data)
+func SM3WithSalt(salt string, data string) string {
+	h := sm3.New()
+	h.Write([]byte(salt))
+	h.Write([]byte(data))
+	return hex.EncodeToString(h.Sum(nil))
+}
+
+// ==================== SM4-ECB 加密/解密 ====================
+
+// SM4ECBEncrypt SM4-ECB模式加密，返回base64编码字符串
+func SM4ECBEncrypt(plaintext []byte, key []byte) (string, error) {
+	if len(key) != 16 {
+		return "", fmt.Errorf("SM4密钥长度必须为16字节")
+	}
+
+	block, err := sm4.NewCipher(key)
+	if err != nil {
+		return "", fmt.Errorf("创建SM4 cipher失败: %v", err)
+	}
+
+	padded := pkcs7Padding(plaintext, block.BlockSize())
+	ciphertext := make([]byte, len(padded))
+	for i := 0; i < len(padded); i += block.BlockSize() {
+		block.Encrypt(ciphertext[i:i+block.BlockSize()], padded[i:i+block.BlockSize()])
+	}
+
+	return base64.StdEncoding.EncodeToString(ciphertext), nil
+}
+
+// SM4ECBDecrypt SM4-ECB模式解密，输入base64编码字符串，返回明文
+func SM4ECBDecrypt(encryptedData string, key []byte) ([]byte, error) {
+	if len(key) != 16 {
+		return nil, fmt.Errorf("SM4密钥长度必须为16字节")
+	}
+
+	ciphertext, err := base64.StdEncoding.DecodeString(encryptedData)
+	if err != nil {
+		return nil, fmt.Errorf("base64解码失败: %v", err)
+	}
+
+	block, err := sm4.NewCipher(key)
+	if err != nil {
+		return nil, fmt.Errorf("创建SM4 cipher失败: %v", err)
+	}
+
+	blockSize := block.BlockSize()
+	if len(ciphertext)%blockSize != 0 {
+		return nil, fmt.Errorf("密文长度不是块大小的整数倍")
+	}
+
+	plaintext := make([]byte, len(ciphertext))
+	for i := 0; i < len(ciphertext); i += blockSize {
+		block.Decrypt(plaintext[i:i+blockSize], ciphertext[i:i+blockSize])
+	}
+
+	plaintext, err = pkcs7UnPadding(plaintext)
+	if err != nil {
+		return nil, fmt.Errorf("去除填充失败: %v", err)
+	}
+
+	return plaintext, nil
+}
+
+// ==================== PKCS7 填充 ====================
+
+func pkcs7Padding(data []byte, blockSize int) []byte {
+	padding := blockSize - len(data)%blockSize
+	padText := make([]byte, padding)
+	for i := range padText {
+		padText[i] = byte(padding)
+	}
+	return append(data, padText...)
+}
+
+func pkcs7UnPadding(data []byte) ([]byte, error) {
+	if len(data) == 0 {
+		return nil, fmt.Errorf("数据为空")
+	}
+	padding := int(data[len(data)-1])
+	if padding > len(data) || padding == 0 {
+		return nil, fmt.Errorf("无效的填充")
+	}
+	for i := len(data) - padding; i < len(data); i++ {
+		if int(data[i]) != padding {
+			return nil, fmt.Errorf("无效的填充")
+		}
+	}
+	return data[:len(data)-padding], nil
+}
+
+// ==================== 时间戳工具 ====================
+
+// GenerateTimestampMillis 生成毫秒级时间戳
+func GenerateTimestampMillis() string {
+	return fmt.Sprintf("%d", time.Now().UnixMilli())
+}
\ No newline at end of file