We have come a long way and have covered almost every aspect of Assembly programming basics. In fact, we should be able to implement any algorithm in Assembly language by this time; however, there are a few important things left we have not touched yet, but they are nonetheless important to know.

Despite the fact that writing relatively large parts of a product (not to say writing a complete product) in Assembly language may not be the best idea when it comes to timelines, it may still be a very interesting and challenging task (educational as well). Sometimes it is more convenient to implement certain parts of an algorithm in Assembly, rather than using a high-level language. Remember the tiny virtual machine we used for XOR encryption of data? For the sake of an example, we will implement a simple encryption/decryption module in Assembly and see how it may be used with high-level languages.

In this chapter, we will cover the following topics:

• Implementing the core of a primitive cryptographic module
• Building object files for further linking with code written in high-level languages:
  • OBJ: Object files for Windows (32 and 64 bit);
  • O: Linkable ELF for Linux (32 and 64 bit);
• Building DLL (dynamic link libraries) and SO (shared objects) for Windows and Linux (32 and 64 bit) to be used with the .NET platform