Any experiences about BLE security with Arduino?

I have been reading a lot about BLE security lately. But, I have found only a bunch of links talking about doing something concrete around ble security: 2. ble security vulnerabilities 3. Open source...
Is it possible to set a memory region from non-secure to secure at runtime?

This question was raised in the ' How to implement a secure IoT system on ARMv8-M ' webinar, view all the questions in the round up blog post .
Small off-the-shelf small ARM module (15mmx25mm or less)?

We are looking for off-the-shelf small ARM module (15mmx25mm or less) with the following specs: - single core >= 100MHz is OK >= 256k RAM >= 256kb ROM >= 2mbit flash - battery charging circuit - uart...
What sort of visibility does a non-secure debugger have of the secure sections?

This question was raised in the ' How to implement a secure IoT system on ARMv8-M ' webinar, view all the questions in the round up blog post .
Does Aarch64 LDTR behave differently in secure vs non-secure?

Can LDTR be used to test requests from secure EL0 or are all results taken in the context of NS EL0?