How can you decode a .dll so it is readable?

Answer 1

WarningDLL files can be vital parts of an operating system. Tampering with them can cause damage to the operating system and stop it working. Take care not to modify code inadvertently.

DLL code cannot be read in a text editor as it is machine readable code or binary. Although many of them will have text imbedded in them, the essence of the code needs to be disassembled before it can be read in any sort of meaningful way. Keep in mind that you won't get the actual original source code back, and it takes a lot of work to figure out what the logic of the DLL is supposed to do. The same is the case for .exe, .com, .cod and .lib files.

What Do DLL Files Do?A DLL file is indicated by the extension DLL in its name. Microsoft gives several definitions of a DLL but the one that I think has the least jargon is this:

"A Dynamic Link Library (DLL) is a file of code containing functions that can be called from other executable code (either an application or another DLL). Programmers use DLLs to provide code that they can reuse and to parcel out distinct jobs. Unlike an executable (EXE) file, a DLL cannot be directly run. DLLs must be called from other code that is already executing."

Another way of putting it is that DLL files are like modules that can be plugged into different programs whenever a program needs the particular features that come with the DLL. The original concept behind DLL files was to simplify things. It was recognized that there were many functions common to a lot of software. For example, most programs need to create the graphical interface that appears on the screen. Instead of having to contain the code to create the interface themselves, programs call on a DLL for that function. The idea is to have a central library where everyone can obtain the commonly used functions, as they are needed. This cuts down on code, speeds things up, is more efficient, etc. They are called dynamic links because they are put to use only when a program calls on them and they are run in the program's own memory space. More than one program can use the functions of a particular DLL at the same time.

Parenthetically, I have to say that the software developers (not least of all, Microsoft) have strayed from the path of keeping things simple. A computer today may contain a thousand or more different DLL files. Also, Microsoft seems to tinker endlessly with DLL files, giving rise to many different versions of a file with the same name, not all compatible. Microsoft maintains a database with information about various DLLs to help with version conflicts.