CRC32 TOOLS + src
 

CRC32 TOOLS:
EASY_CRC.exe - easy CRC calculator
CRC_CRACKER.exe - change last dword of file in order to give target CRC;
CRC reverser tool

source code included.

Is there any protection scheme that uses the CRC32? I mean, any practical application of this for cracking?

I will try to help answer your very notice question in a way you can understand as you seem to be very new to this field.

CRC32 is not a security mechanism, it is an integrity mechanism. Sure bad security implementations by amateurs might do it. Data integrity is done through machine authentication codes or public private key security in a security context.

Its like asking would you use a Mersenne Twister pseudo random number generator as an algo in a security mechanism instead of a cryptographicly secure one. A product you've likely not encountered before called IDA Pro actually did use the MT PRNG for its key generation with 32 bit seeds which made a small state space to search for all possible keys.

CRC is used in many ways to check integrity of code segments by packers to identify signs of tampering or corruption.
Major packers including VMProtect, Themida, etc. make extensive use of CRC checks to prevent memory patching of processes.
CRC32 could also be used by some protectors for fast integrity check of whole files.
The tool that CodeCracker provided is for a slightly different use though.

You gave 3 examples of data integrity checking which is what I just said. It's not security even if it's a part of protection software. This would fall under security by obscurity which is not security at all. So now you have learned something new, obviously.

Could be possible to upload externally?

Just grab it off TUTS4YOU.