diff --git a/Flakkari/Engine/EntityComponentSystem/Entity.hpp b/Flakkari/Engine/EntityComponentSystem/Entity.hpp
index 6ee6464e..f3babb1f 100644
--- a/Flakkari/Engine/EntityComponentSystem/Entity.hpp
+++ b/Flakkari/Engine/EntityComponentSystem/Entity.hpp
@@ -43,10 +43,28 @@ class Entity {
         return *this;
     }
 
+    bool operator==(const Entity& other) const {
+        return _id == other._id;
+    }
+
+    std::size_t getId() const { return _id; }
+
 private:
     std::size_t _id;
 };
 
 } // namespace Flakkari::Engine::ECS
 
+#include <unordered_map>
+
+namespace std {
+    template <>
+    struct hash<Flakkari::Engine::ECS::Entity>
+    {
+        size_t operator()(const Flakkari::Engine::ECS::Entity& entity) const noexcept {
+            return std::hash<std::size_t>()(entity.getId());
+        }
+    };
+}
+
 #endif /* !FLAKKARI_ENTITY_HPP_ */
diff --git a/Flakkari/Protocol/Header.hpp b/Flakkari/Protocol/Header.hpp
index 20686eef..ed24e720 100644
--- a/Flakkari/Protocol/Header.hpp
+++ b/Flakkari/Protocol/Header.hpp
@@ -28,9 +28,9 @@
 
 namespace Flakkari::Protocol {
 
-using ushort = unsigned short; // 16 bits (max: 65535)
-using uint = unsigned int;     // 32 bits (max: 4294967295)
-using ulong = unsigned long;   // 64 bits (max: 18446744073709551615)
+using ushort = uint16_t; // 16 bits (max: 65535) (2 bytes)
+using uint = uint32_t;     // 32 bits (max: 4294967295) (4 bytes)
+using ulong = uint64_t;   // 64 bits (max: 18446744073709551615) (8 bytes)
 
 /**
  * @brief The version of the protocol used
@@ -78,14 +78,28 @@ inline namespace V_1 {
 
 LPL_PACKED_START
 
+/**
+ * @brief Flakkari Header v1 (new header)
+ *
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |Priority|Api V.|   CommandId   |       ContentLength           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                        SequenceNumber                         |
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
 template <typename Id> struct Header {
     Priority _priority     : 4 = Priority::LOW;
     ApiVersion _apiVersion : 4 = ApiVersion::V_1;
     Id _commandId;
-    ushort _contentLength = 0;
-    uint _sequenceNumber = static_cast<uint>(
-        std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now().time_since_epoch())
+    uint16_t _contentLength = 0;
+    uint64_t _sequenceNumber =
+        static_cast<uint64_t>(std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now().time_since_epoch())
             .count());
+
+    std::size_t size() const { return sizeof(*this); }
 };
 
 LPL_PACKED_END
diff --git a/Flakkari/Protocol/Packet.hpp b/Flakkari/Protocol/Packet.hpp
index 47908f98..49ac8af7 100644
--- a/Flakkari/Protocol/Packet.hpp
+++ b/Flakkari/Protocol/Packet.hpp
@@ -153,9 +153,9 @@ template <typename Id> struct Packet {
      */
     [[nodiscard]] bool deserialize(const Network::Buffer &buffer)
     {
-        if (buffer.size() < sizeof(header))
+        if (buffer.size() < header.size())
             return FLAKKARI_LOG_WARNING("Buffer is too small to deserialize a packet."), false;
-        std::memcpy(&header, buffer.data(), sizeof(header));
+        std::memcpy(&header, buffer.data(), header.size());
         if (header._priority >= Priority::MAX_PRIORITY)
             return FLAKKARI_LOG_WARNING("Priority is too big (" + std::to_string((int) header._priority) + ")"), false;
         if (header._apiVersion >= ApiVersion::MAX_VERSION)
@@ -164,9 +164,9 @@ template <typename Id> struct Packet {
         if (header._commandId >= CommandId::MAX_COMMAND_ID)
             return FLAKKARI_LOG_WARNING("CommandId is too big (" + std::to_string((int) header._commandId) + ")"),
                    false;
-        if (header._contentLength > buffer.size() - sizeof(header))
+        if (header._contentLength > buffer.size() - header.size())
             return false;
-        payload = buffer.extractData(sizeof(header), header._contentLength);
+        payload = buffer.extractData(header.size(), header._contentLength);
         return true;
     }
 };