Helper function for producing hashes of files.

MD5HashFile.cs

static string MD5HashFile(string path, int readBufferSize = 0xFFFF)
{
	if (path == null) throw new ArgumentNullException(nameof(path));
	if (readBufferSize < 1) throw new ArgumentOutOfRangeException(nameof(readBufferSize), "The read buffer size cannot be less than 1");

	var readBuffer = new byte[readBufferSize];

	using (var stream = File.OpenRead(path))
	using (var hasher = MD5.Create())
	{
		while (true)
		{
			var bytesRead = stream.Read(readBuffer, 0, readBufferSize);
			if (bytesRead == 0)
				break;
			hasher.TransformBlock(readBuffer, 0, bytesRead, null, 0);
		}

		hasher.TransformFinalBlock(Array.Empty<byte>(), 0, 0);

		return BitConverter.ToString(hasher.Hash)
						   .Replace("-", string.Empty)
						   .ToLower();
	}
}