dsSHA is a System Utilities software developed by Dariusz Stanislawek. After our trial and test, the software is proved to be official, secure and free. Here is the official description for dsSHA:
dsSHA produces SHA-1 digital file signature. Like CRC or MD5 it can be used for detection of file tampering by viruses, hackers, etc. and integrity verification of copied or downloaded files. dsSHA is so small that it could be simply included in distribution packages. dsSHA is fast, dependency-free and does not need things like MFC or VB. you can free download dsSHA 1.02 now.