ExactFile is a file integrity verification tool. You can use it to make sure that files you copy or distribute are undamaged and unaltered.
ExactFile reads a file (or group of files) and creates a checksum for each file that can be used to test the files at a later time, ensuring that they have not been altered or damaged. The checksum is a "signature" of a file created with a hash routine. A change of even one byte in a file will change its checksum value. ExactFile supports several different hash routines, including the most common (MD5, CRC32, and SHA1). Each hash method has advantages and disadvantages pertaining to computation time, checksum length, and collision potential. It is not important to understand these technical details to use ExactFile.