rev: add a few more challenges

rev/vault_door_training/VaultDoorTraining.java

@@ -0,0 +1,26 @@
+import java.util.*;
+
+class VaultDoorTraining {
+    public static void main(String args[]) {
+        VaultDoorTraining vaultDoor = new VaultDoorTraining();
+        Scanner scanner = new Scanner(System.in); 
+        System.out.print("Enter vault password: ");
+        String userInput = scanner.next();
+	String input = userInput.substring("picoCTF{".length(),userInput.length()-1);
+	if (vaultDoor.checkPassword(input)) {
+	    System.out.println("Access granted.");
+	} else {
+	    System.out.println("Access denied!");
+	}
+   }
+
+    // The password is below. Is it safe to put the password in the source code?
+    // What if somebody stole our source code? Then they would know what our
+    // password is. Hmm... I will think of some ways to improve the security
+    // on the other doors.
+    //
+    // -Minion #9567
+    public boolean checkPassword(String password) {
+        return password.equals("w4rm1ng_Up_w1tH_jAv4_eec0716b713");
+    }
+}

rev/vault_door_training/flag.txt

@@ -0,0 +1 @@
+picoCTF{w4rm1ng_Up_w1tH_jAv4_eec0716b713}