public static string Checksum(string filePath)
{
using (var fs = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
using (var bs = new BufferedStream(fs))
{
using (var sha1 = new SHA1Managed())
{
byte[] hash = sha1.ComputeHash(bs);
return ChecksumToString(hash);
}
}
}