diff --git a/entities/IEntity.h b/entities/IEntity.h
new file mode 100644
index 0000000..faeddfb
--- /dev/null
+++ b/entities/IEntity.h
@@ -0,0 +1,12 @@
+#ifndef IENTITY_H
+#define IENTITY_H
+
+#include "ISerializable.h"
+
+
+class IEntity : public ISerializable {
+public:
+   virtual unsigned long long id() = 0;
+};
+
+#endif // IENTITY_H
diff --git a/entities/ISerializable.h b/entities/ISerializable.h
new file mode 100644
index 0000000..b1d5022
--- /dev/null
+++ b/entities/ISerializable.h
@@ -0,0 +1,23 @@
+#ifndef ISERIALIZABLE_H
+#define ISERIALIZABLE_H
+
+#include <QDataStream>
+
+
+class ISerializable {
+public:
+    virtual void serialize(QDataStream &output) = 0;
+    virtual void deserialize(QDataStream &input) = 0;
+
+    friend QDataStream &operator<<(QDataStream &output, ISerializable &s) {
+        s.serialize(output);
+        return output;
+    }
+
+    friend QDataStream &operator>>(QDataStream  &input, ISerializable &s) {
+        s.deserialize(input);
+        return input;
+    }
+};
+
+#endif // ISERIALIZABLE_H
diff --git a/entities/cargo_entity.cpp b/entities/cargo_entity.cpp
index e5a6f02..b24a177 100644
--- a/entities/cargo_entity.cpp
+++ b/entities/cargo_entity.cpp
@@ -19,3 +19,11 @@ QString cargo_entity::title() {
 unsigned int cargo_entity::volume() {
     return this->_volume;
 }
+
+void cargo_entity::serialize(QDataStream &output) {
+    output << this->_id << this->_title << this->_volume;
+}
+
+void cargo_entity::deserialize(QDataStream &input) {
+    input >> this->_id >> this->_title >> this->_volume;
+}
diff --git a/entities/cargo_entity.h b/entities/cargo_entity.h
index 1aed358..cbf00c8 100644
--- a/entities/cargo_entity.h
+++ b/entities/cargo_entity.h
@@ -1,12 +1,13 @@
 #ifndef CARGO_ENTITY_H
 #define CARGO_ENTITY_H
 
+#include "IEntity.h"
+
 #include <QString>
 #include <QCryptographicHash>
 
 
-class cargo_entity
-{
+class cargo_entity : public IEntity {
 private:
     unsigned long long _id;
     QString _title;
@@ -19,6 +20,9 @@ public:
     unsigned long long id();
     QString title();
     unsigned int volume();
+
+    void serialize(QDataStream &output);
+    void deserialize(QDataStream &input);
 };
 
 #endif // CARGO_ENTITY_H
diff --git a/entities/dpoint_entity.cpp b/entities/dpoint_entity.cpp
index 60e17e8..fd43073 100644
--- a/entities/dpoint_entity.cpp
+++ b/entities/dpoint_entity.cpp
@@ -19,3 +19,11 @@ QString dpoint_entity::title() {
 const QVector<unsigned long long> dpoint_entity::storages_ids() {
     return this->_storages_ids;
 }
+
+void dpoint_entity::serialize(QDataStream &output) {
+    output << this->_id << this->_title << this->_storages_ids;
+}
+
+void dpoint_entity::deserialize(QDataStream &input) {
+    input >> this->_id >> this->_title >> this->_storages_ids;
+}
diff --git a/entities/dpoint_entity.h b/entities/dpoint_entity.h
index c36154f..e431dca 100644
--- a/entities/dpoint_entity.h
+++ b/entities/dpoint_entity.h
@@ -1,13 +1,14 @@
 #ifndef DPOINT_ENTITY_H
 #define DPOINT_ENTITY_H
 
+#include "IEntity.h"
+
 #include <QString>
 #include <QVector>
 #include <QCryptographicHash>
 
 
-class dpoint_entity
-{
+class dpoint_entity : public IEntity {
 private:
     unsigned long long _id;
     QString _title;
@@ -20,6 +21,9 @@ public:
     unsigned long long id();
     QString title();
     const QVector<unsigned long long> storages_ids();
+
+    void serialize(QDataStream &output);
+    void deserialize(QDataStream &input);
 };
 
 #endif // DPOINT_ENTITY_H
diff --git a/entities/storage_entity.cpp b/entities/storage_entity.cpp
index b198c38..83f65a1 100644
--- a/entities/storage_entity.cpp
+++ b/entities/storage_entity.cpp
@@ -19,3 +19,11 @@ unsigned int storage_entity::capacity() {
 const QVector<cargo_entity> storage_entity::cargo() {
     return this->_cargo;
 }
+
+void storage_entity::serialize(QDataStream &output) {
+    output << this->_id << this->_capacity << this->_cargo;
+}
+
+void storage_entity::deserialize(QDataStream &input) {
+    input >> this->_id >> this->_capacity >> this->_cargo;
+}
diff --git a/entities/storage_entity.h b/entities/storage_entity.h
index a8442be..40210fe 100644
--- a/entities/storage_entity.h
+++ b/entities/storage_entity.h
@@ -1,14 +1,14 @@
 #ifndef STORAGE_ENTITY_H
 #define STORAGE_ENTITY_H
 
+#include "IEntity.h"
 #include "cargo_entity.h"
 
 #include <QVector>
 #include <QCryptographicHash>
 
 
-class storage_entity
-{
+class storage_entity : public IEntity {
 private:
     static unsigned long long __global_id;
 
@@ -23,6 +23,9 @@ public:
     unsigned long long id();
     unsigned int capacity();
     const QVector<cargo_entity> cargo();
+
+    void serialize(QDataStream &output);
+    void deserialize(QDataStream &input);
 };
 
 #endif // STORAGE_ENTITY_H
diff --git a/entities/user_entity.cpp b/entities/user_entity.cpp
index ac98ab6..ef8508c 100644
--- a/entities/user_entity.cpp
+++ b/entities/user_entity.cpp
@@ -1,6 +1,6 @@
 #include "user_entity.h"
 
-user_entity::user_entity(const QString &login, const QString &password, UserRole role) {
+user_entity::user_entity(const QString &login, const QString &password, UserRole role) : _login(login), _role(role) {
     this->_pwd_hash = QCryptographicHash::hash(password.toLocal8Bit(), QCryptographicHash::Sha3_256);
 }
 
@@ -19,3 +19,11 @@ UserRole user_entity::role() {
 bool user_entity::verify_password(const QString &password) {
     return (this->_pwd_hash == QCryptographicHash::hash(password.toLocal8Bit(), QCryptographicHash::Sha3_256));
 }
+
+void user_entity::serialize(QDataStream &output) {
+    output << this->_id << this->_login << this->_role << this->_pwd_hash;
+}
+
+void user_entity::deserialize(QDataStream &input) {
+    input >> this->_id >> this->_login >> this->_role >> this->_pwd_hash;
+}
diff --git a/entities/user_entity.h b/entities/user_entity.h
index a085969..cf87e8e 100644
--- a/entities/user_entity.h
+++ b/entities/user_entity.h
@@ -1,6 +1,8 @@
 #ifndef USER_ENTITY_H
 #define USER_ENTITY_H
 
+#include "IEntity.h"
+
 #include <QString>
 #include <QCryptographicHash>
 
@@ -10,8 +12,7 @@ enum class UserRole {
 };
 
 
-class user_entity
-{
+class user_entity : public IEntity {
 private:
     unsigned long long _id;
     QString _login;
@@ -26,6 +27,9 @@ public:
     const QString login();
     UserRole role();
     bool verify_password(const QString &password);
+
+    void serialize(QDataStream &output);
+    void deserialize(QDataStream &input);
 };
 
 #endif // USER_ENTITY_H
diff --git a/entities/vessel_entity.cpp b/entities/vessel_entity.cpp
index 7b0dada..a5b99a0 100644
--- a/entities/vessel_entity.cpp
+++ b/entities/vessel_entity.cpp
@@ -22,3 +22,11 @@ unsigned int vessel_entity::capacity() {
 const QVector<cargo_entity> vessel_entity::cargo() {
     return this->_cargo;
 }
+
+void vessel_entity::serialize(QDataStream &output) {
+    output << this->_id << this->_harbor << this->_capacity << this->_cargo;
+}
+
+void vessel_entity::deserialize(QDataStream &input) {
+    input >> this->_id >> this->_harbor >> this->_capacity >> this->_cargo;
+}
diff --git a/entities/vessel_entity.h b/entities/vessel_entity.h
index 2d02c54..a0c6004 100644
--- a/entities/vessel_entity.h
+++ b/entities/vessel_entity.h
@@ -1,13 +1,12 @@
 #ifndef VESSEL_ENTITY_H
 #define VESSEL_ENTITY_H
 
+#include "IEntity.h"
 #include "cargo_entity.h"
 #include "dpoint_entity.h"
 
 
-
-class vessel_entity
-{
+class vessel_entity : public IEntity {
 private:
     static unsigned long long __global_id;
 
@@ -24,6 +23,9 @@ public:
     const dpoint_entity harbor();
     unsigned int capacity();
     const QVector<cargo_entity> cargo();
+
+    void serialize(QDataStream &output);
+    void deserialize(QDataStream &input);
 };
 
 #endif // VESSEL_ENTITY_H
diff --git a/sea_transport.pro b/sea_transport.pro
index a1be585..447f7ce 100644
--- a/sea_transport.pro
+++ b/sea_transport.pro
@@ -26,6 +26,8 @@ HEADERS += \
     authwindow.h \
     cargoeditdialog.h \
     deliverypointeditdialog.h \
+    entities/IEntity.h \
+    entities/ISerializable.h \
     entities/cargo_entity.h \
     entities/dpoint_entity.h \
     entities/storage_entity.h \