Enhance security of the Digital Safe

[celticr]

Originally created by @boolean5 on 2025-12-24T16:05:35Z
Original issue: SpringACT/digital-safe-upload-on-blob#722

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Let's do the following:

• 1. https://github.com/SpringACT/digital-safe-upload-on-blob/issues/719
• 2. https://github.com/SpringACT/digital-safe-upload-on-blob/issues/720
• 3. https://github.com/SpringACT/digital-safe-upload-on-blob/issues/721