If you do not want others to download or modify the learning content that you upload to SoftChalk Cloud, do not make it public. Instead, when publishing the content to Cloud, make it private. Private learning content on Cloud can only be viewed or accessed if you provide the download link to others.
For more details on SoftChalk Cloud, please see the FAQ:
How do I get started with SoftChalk Cloud?, the SoftChalk Cloud Guide and the SoftChalk Cloud website.