Cracks are typically small programs or files created by reverse engineering groups ("cracking groups") or independent reverse engineers ("crackers"). In most of cases, cracks are created to remove, modify or disable certain restrictions of specific software. Those restrictions ("software protection") are usually placed by software manufacturers to prevent using their software without obtaining a paid license.

Here are the most typical ways of protecting software from "unauthorized" use:

Time limit - (shareware) - a program works for certain period of time, and then stops working. To continue using the program, a user has to pay a fee to the software manufacturer (buy or "register" the program")

Demo limit - (shareware) - a program works with only some of its features enabled; usually the most important / attractive features are disabled in the demo. User must buy the program to get the "Full version", which has all the features enabled.

Usage limit - (shareware) - a program works with all its featured enabled, but is either limited to a certain number of launches, or a total time of work, or a number of certain actions, for example, saving the work.

Copy protection - (retail software) - usually, this type of restriction is placed on full retail versions of software that come on digital media storage like CDs, DVDs etc. This protection only prevents users from making copies and installing software on several machines without buying the license.

Disc protection - (games) - this protection is usually used in games; you have to keep the original CD or DVD in drive to be able to play the game.

Dongle protection - (different) - uses a special encryption device called dongle, which authorizes use of a program after it's plugged into your PC (for example, into a USB port).

There are many other types of software protection, from very simple to extremely sophisticated. Removing, disabling or circumventing that protection is a very difficult and interesting challenge for the reverse engineer (cracker). By removing protection (which is designed to be extremely difficult to remove), cracker "defeats" the programmer (or whole programming teams) responsible for creating the protection algorythm. After the program is cracked, crackers usually distribute cracks they created, to demonstrate their capabilities (and weaknesses of their counterparts) to the world.

Strictly speaking, cracks are special programs that "crack" software protection when ran; however, it is generally accepted that anything that makes possible to remove the protection is called a "crack", even though it has nothing to do with reverse engineering. We will follow that rule to keep things simple.

There are several basic types of cracks:

Serial codes (serials). This is the simplest type of crack. Very often it has nothing to do with cracking or crackers. Serial is a special text code given by software manufacturer to anyone who buys software license to remove trial / demo limitations, usually by simply pasting that code into appropriate registration field of the program.

Crackers get those codes by the means of reverse engineering, by understanding how the registration algorithm works and generating serial code that would "register" the software. Non-crackers often get the serials by "stealing" them from license owners, "buying" programs with fake / stolen credit cards etc, and then distribute the serials over the Internet. Naturally, this has nothing to do with cracking and crackers.

It is generally very easy for software manufacturers to counter the distribution of serials. Normally, all they have to do is "blacklist" stolen / widely available serial in the next version of their software or their online database (if software is registered online). Little wonder very many older serials for programs are not working anymore, especially on newer versions!

Registration files (regfiles or keyfiles). Essentially, this type of crack works in the same way as Serial, except that user is given a special file (generated by an algorithm known only to the software maker), instead of a simple text code, to register the program. Regfiles are usually either special (and often encrypted) files, or simple Windows Registry (.reg) files. It is much harder for a cracker, though, to crack this type of protection, as he must understand the keyfile generation algorithm.

As you could have guessed, its equally easy for software manufacturers to counter regfiles' distribution, as it happens with serials – a simple blacklisting will work.

Serial generators (keygenerators, keymakers, keygens). This type of cracks is much harder to create than previous ones, as the cracker must not only fully understand the serial code generation algorithm, but also be able to recreate it! Keygens often take days and even weeks to write; however, a working keygen is a demonstration of a total and clean "victory" of the cracker over the protection creator.

Countering keygen distribution is much harder for the software manufacturer; in most of cases they will have to totally change the serial generation algorithm (a simple change will result in subsequent simple and fast cracking by the same cracker).

Patches. This is the most widespread type of cracks. A patch is a small program that alters the target software files to remove or modify the part of code that is responsible for protection limitations or registration process. As a result, the patch either makes software "think" it is registered, or simply removes limitations like time limit, nag screens, enables non-working features etc. A simple protection patch is usually easy to create by comparing binary code of registered version and "trial" version and then creating a "difference patch" using certain software. Most of patches are hard to create though and require a thorough knowledge of Assembler programming language and good reverse engineering skills.

One disadvantage of patches is that if the cracker is not good / experienced enough, he might accidentally alter a part of code that is needed for normal functioning of the program. Some software manufacturers intentionally "mix" protection code with program code to make it hard for crackers to write a patch; however, experienced crackers eat such tricks with lunch.

Countering patches is usually not a very hard task for software manufacturers; in most cases, a simple software version update renders the patch useless, because patches modify the binary code and are usually created to modify specific parts in that code, which won't work if code differs (even slightly) from the original. Some software makers try to trick crackers by releasing "silent updates": software has exactly the same version and even date of release, but different binary code. Crackers counter this by either releasing several versions of crack with "Silent update" note, or creating a "Generic" crack that works with all versions of software release.

Loaders. Technically, loaders are a variation of patches, except that they modify binary code AFTER the program is ran, i.e. loaded into computer memory. Usually, loaders are used to crack software with encrypted binary files, which make it very hard to write a normal patch.

Pre-cracked files ("cracked EXE"). This type of cracks includes parts of software itself, already altered by cracker. Cracked EXEs are extremely hard or even impossible to counter by software manufacturers, and are considered by some as "unfair play".

Ok, now we know about types of cracks and what they do. How to correctly use them?

First of all, scan the downloaded file with a GOOD antivirus. We recommend doing this with any executable file downloaded from the Internet. Remember, crackers never infect their cracks with viruses; as one famous cracker said, "I am not going to spend weeks of work to steal your ICQ password or format your harddisk". However, crack files might get infected on the way from a cracker to the end user, so ALWAYS, ALWAYS scan cracks with antiviruses before running.

Second, READ THE NFO! Most of crack packages include brief instruction on how to use that specific crack, which is usually located in NFO or TXT files supplied with the package. ALWAYS read NFO before running the crack. It may contain very important instructions; reading NFO will save you from many problems later.

Now you are ready to unpack and run the crack (if it's a program). If it's a patch or a loader, you need to close target software first. Follow the NFO instructions carefully. Remember that some cracks don't work as intended; there can be a bug in crack, or target program protection might be already updated. In such cases, you might need to either get older version of program, or a newer / working version of a crack.

If the crack worked, the program should now run without any limitations you wished to remove. Congratulations!

Now, we have a piece of cracked software. Can I use it? What about legal issues?

Well, it all depends on your local legislation. It is obvious that software manufacturers do not have moral right to make their software freely available to the world (for example, "shareware" software), and then require you to strictly follow a thing called "Window with End User License Agreement (EULA), which is accepted when you press I ACCEPT button", no matter in what country you are located. Laws of many countries do not recognize legal power of an agreement made between a computer and a human, especially when those agreements are signed by pressing mouse buttons. If EULA conflicts with your local law, you are free to violate that EULA and do anything it disallows, including cracking, disassembling, reverse engineering, changing its name to ShitSoft CrapOffice etc. However, REMEMBER that the program still remains a copyrighted piece of work, which means that you must follow your local copyright laws if you are concerned. In most of cases, you don't have right to distribute it; whether you can use it beyond trial limit, again, depends on your local law. Consult your lawyer if you are THAT worried.

Thanks for reading our small guide; we hope that it helped you or at least was interesting to read. We will update it regularly and add more information, please check back!