Metatrader. Protection from MQL decompiling

A little bit of theory.

Expert advisors, indicators and scripts for the Metatrader system are created using the built-in MQL language. Then, the source text code MQ4 is compiled into executable binary code EX4. File with the EX4 extension contains program logic understandable to the Metatrader interpreter only. We will not see anything using ordinary text editor. This is convenient in case if a programmer or trader provide their program for usage but doesn’t want the user to know the details of the sales strategy.

A problem.

Unfortunately, there are methods of decompiling the EX4 files back to MQ4 which allow seeing the program logic. This is a big problem for those who want to keep the details of their trading strategy confidential.

Decompiling makes it pointless to create a business that is based on sales of expert advisors or providing them for usage. The existing companies suffer great losses.

Solution methods.

There is an opinion that a good MQL programmer can write program in a way that would make it impossible to decompile. For example, by using licensing system. Well, unfortunately this is not the case. The strategy cannot be protected by means of MQL only.

Let us see several methods of protecting sales strategies. We will compare them and find out their pros and cons.

1. Pure MQL

As we have already said, this method does not provide protection because an EX4 file can be easily decompiled. However, along with the cons, MQL programming has its pros which will be examined in comparison with the other methods.

Pros: simple structured language that is comprehensible by traders and not only by specialists. Lowest cost level as compared to other methods.

Cons: easily decompiled.

Special features: applicable for personal use or for refinement of the strategies logic.

2. DLL

MQL language has a very useful special feature. It allows the programs to link with the libraries (DLL) written in other programming languages. First of all, it essentially expands the possibilities and secondly, it allows moving MQL logic into the library which makes decompiling of an EX4 file useless.

DLL can also be decompiled however it is by no means easy and requires specific knowledge. When decompiled, the DLL code is translated into the Assembler (ASM) machine language. This procedure is called disassembly. Pay level of ASM specialists is very high, thus such expenses are unreasonable for hacking most projects.

Moreover, a project consists of two parts minimum: MQL+DLL, which makes the hacking job even more complicated, since it requires teamwork of two specialists.

Pros: quite a high protection level, unlimited capacity to expand possibilities of the MQL language.

Cons: higher development cost as compared to an MQL project. Library installation required.

Special features: applicable for projects of average cost and popularity.

3. Online WEB

This method implies moving of the trade logic to WEB server. The user’s computer will have executive interface only, without the decision-making module.

MQL, DLL and WEB are used in this architecture. MQL generates a request, DLL sends it to WEB server, and the server generates and sends a reply that gets into MQL through DLL. MQL manages the orders based on the reply.

There are simpler variants, when MQL only listens to / monitors the replies from WEB server.

Pros: The highest protection. Possibility of remote updates. Possibility of remote control over access to the project.

Cons: Delays can occur during data synchronization. High development cost.

Special features: Applicable for major or popular projects.

Comparison.

The comparison was made by specialists of AirBionicFX company. Explanation of the results and comparison criteria are given below each diagram.

By protection level

Minimum is 0, Maximum is 10. The more, the better.

• MQL – 1
• DLL – 6
• WEB – 9

MQL has minimal protection against hacking, but 1 point is scored considering that it is not every user who knows about decompiling and not everyone knowing it would be ready to use this method.

DLL has average protection level.

WEB has almost maximum protection level. One point is not scored because there is a probability to hack WEB server that stores the strategy logic. Such probability is very low and even if it happens, then a specialist is needed to decompile binary code and then synchronize the logic with the MQL.

The following factors were considered when estimating the protection level:

• Statistics of users’ awareness of the decompiling possibility;
• Complexity of decompiling process for each of the methods;
• Cost of hacking job specialists.

By development cost

Minimum is 0, Maximum is 10. The less, the better.

• MQL – 1
• DLL – 4
• WEB – 10

The results can be explained as follows. If we take any task and fulfill it using all methods, then MQL will be the most low-cost one, WEB is the most expensive, and DLL will have the cost a little less than average as per the maximum level.

The following factors were considered when estimating the development cost:

Cost of work done by specialists in each area;

Complexity and time for testing a ready project.

By speed of decision-making

Minimum is 0, Maximum is 10. The more, the better.

• MQL – 10
• DLL – 9-6
• WEB – 6-1

Speed of decision-making is like the other side of a coin while the first side is protection. The more components the system has, the more problems will be there with data synchronization. Accordingly, WEB method will be the slowest. DLL will be average, and MQL – the fastest.

For DLL, a range of speed values is given. If DLL is used as a library for computations, then the processing speed will be practically comparable with the MQL and will have an index of 9 points. And if synchronization with the external data sources is used within DLL, then the speed index may fall to 6 points.

Same for WEB. If the logic is simple and it is executed fast, then the speed index will be not lower than 6 points. And if, for example, WEB server is connected with Back Office for computation of expert advisor values, then the speed index may fall to the minimal value.

The following factors were considered when estimating the speed of decision-making:

Project architecture;

Connection with external data sources.

Conclusion

When selecting a method of protection, you have to consider all the parameters described above. Then the facilities committed for the development will pay off over and above and the ill-wishers will be left with nothing!

Have a nice trade!