add(接口)：添加授权、用户、好友关系服务接口

backend/IM_API/Tools/PasswordHasher.cs

@@ -0,0 +1,22 @@
+using System.Security.Cryptography;
+using System.Text;
+
+namespace IM_API.Tools
+{
+    public static class PasswordHasher
+    {
+        public static string HashPassword(string password)
+        {
+            using var sha256 = SHA256.Create();
+            var hashedBytes = sha256.ComputeHash(Encoding.UTF8.GetBytes(password));
+            return Convert.ToBase64String(hashedBytes);
+        }
+
+        public static bool VerifyPassword(string password, string hashedPassword)
+        {
+            var hashedInput = HashPassword(password);
+            return hashedInput == hashedPassword;
+        }
+    }
+}
+}