Step 1: Understanding execution pending appeal.
Order 41 Rule 5 of the CPC empowers the Appellate Court to stay execution of a decree and order security when the judgment-debtor appeals.
Step 2: Applying the rule.
It is only the Appellate Court that has the authority to direct the subordinate court to take security or stay execution of the decree.
Step 3: Conclusion.
Thus, the Appellate Court—not the High Court, police, or registrar—can direct security.