crc32/checksum app

I'd like to write a C++ app program that would store a list of files (by relative path/location) plus it's CRC32 or checksum. Then it would also store more CRC32/checksums for the same file, for each snapshot in time.

The main usage of the app would be to help identify which versions of the current folder contents are.

Does anyone know such program already exist? If not, how to write in C++ with common libraries (boost, etc)?

There is info on the CRC algorithm here. Its a really simple algorithm but if you dont fancy wrapping it yourself theres always Boosts CRC library. Standard C++ and Boost filesystem should take care of the rest.