diff --git a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Action.java b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Action.java
index 0902f40..f4cc2f2 100644
--- a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Action.java
+++ b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Action.java
@@ -18,6 +18,11 @@ public class Action extends OperationBase {
         product.setStateToReadyForDispatch();
     }
 
+    public void endAction() {
+        this.setTimeEnd();
+        product.setStateToAvailable();
+    }
+
     public IOperation getLastOperation() {
         return lastOperation;
     }
diff --git a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/OperationBase.java b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/OperationBase.java
index b6bbbca..40e4ea3 100644
--- a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/OperationBase.java
+++ b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/OperationBase.java
@@ -25,8 +25,8 @@ public class OperationBase {
         return timeEnd;
     }
 
-    public void setTimeEnd(LocalDateTime timeEnd) {
-        this.timeEnd = timeEnd;
+    public void setTimeEnd() {
+        this.timeEnd = LocalDateTime.now();
     }
 
     public INode getNodeCreator() {
diff --git a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/ProductTransaction.java b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/ProductTransaction.java
index c3d6994..73061ee 100644
--- a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/ProductTransaction.java
+++ b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/ProductTransaction.java
@@ -18,6 +18,12 @@ public class ProductTransaction extends Transaction {
         product.setStateToReadyForDispatch();
     }
 
+    @Override
+    public void endTransaction() {
+        super.endTransaction();
+        product.setStateToAvailable();
+    }
+
     public IOperation getLastOperation() {
         return lastOperation;
     }
diff --git a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Transaction.java b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Transaction.java
index fa22bd2..54a0e72 100644
--- a/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Transaction.java
+++ b/src/main/java/cz/cvut/fel/sit/omo/foodchain/operation/Transaction.java
@@ -17,6 +17,10 @@ public abstract class Transaction extends OperationBase {
         signature = SignatureManager.signTransaction(this);
     }
 
+    public void endTransaction() {
+        this.setTimeEnd();
+    }
+
     public TransactionType getTransactionType() {
         return transactionType;
     }
diff --git a/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/Signature.java b/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/Signature.java
index 8163663..865981c 100644
--- a/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/Signature.java
+++ b/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/Signature.java
@@ -3,17 +3,20 @@ package cz.cvut.fel.sit.omo.foodchain.signature;
 import cz.cvut.fel.sit.omo.foodchain.operation.Transaction;
 
 import java.time.LocalDateTime;
+import java.util.UUID;
 
 public class Signature {
 
-    private String managerCode;
-    private Transaction transaction;
-    private LocalDateTime signedDate;
+    private final String managerCode;
+    private final Transaction transaction;
+    private final LocalDateTime signedDate;
+    private final UUID uuid;
 
     public Signature(String code, Transaction transaction) {
         managerCode = code;
         this.transaction = transaction;
         signedDate = LocalDateTime.now();
+        uuid = UUID.randomUUID();
     }
 
     public Transaction getTransaction(String code) {
@@ -27,4 +30,10 @@ public class Signature {
             return signedDate;
         return null;
     }
+
+    public UUID getUuid(String code) {
+        if (code.equals(managerCode))
+            return uuid;
+        return null;
+    }
 }
diff --git a/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/SignatureManager.java b/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/SignatureManager.java
index 03db230..233468c 100644
--- a/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/SignatureManager.java
+++ b/src/main/java/cz/cvut/fel/sit/omo/foodchain/signature/SignatureManager.java
@@ -11,6 +11,7 @@ public class SignatureManager {
     }
 
     public static boolean validateSignature(Transaction transaction) {
-        return transaction == transaction.getSignature().getTransaction(MANAGER_CODE);
+        return transaction.equals(transaction.getSignature().getTransaction(MANAGER_CODE))
+                && transaction.getSignature().getUuid(MANAGER_CODE).equals(transaction.getSignature().getTransaction(MANAGER_CODE).getSignature().getUuid(MANAGER_CODE));
     }
 }