# Security considerations

## Introduction

This document dives into the knowledge base of security considerations for Vision developers. For any new findings, feel free to contribute by using the suggest edits button.

## Contents

* User/Developer Entropy Pay Ratio describes how to prevent account draining attacks.
* Fee Limit on Deploy/Execution describes range limits and where to set limit.
* Frozen Entropy and Out of Entropy describes the maximum entropy limit formula and its applications.
* Timeout and Infinite Loop Pitfalls guides developers on how to best avoid these pitfalls.
* Illegal Operations and Penalties describes how invalid operation codes could be triggered, and best practices to avoid it.
* Non-Existent Account Transfers and Penalties describes how to avoid the non-existent account transfer penalty.
* Developer Entropy Cost Protection describes the Developer Origin Entropy Limit parameter, its purpose, and how to set this parameter.
* Fallback Functions guides developers on the implementation of this class of functions within smart contracts.