use secure_malloc get large memory from __uvisor_public_sram region，is it secure？

From the document，I find the SRAM is divided into two regin，In my application，I need
dynamically allocate large memory.and the heap size belongs secure BOX is not enough.
so I need get memory from " __uvisor_public_sram"
and store some data .

Is the data safe？

Start with the document section describing the two SRAM regions and then locate the definitions or documentation for secure_malloc and __uvisor_public_sram. Determine whether data stored in that region is protected from secure BOX code or other callers, and document the security boundary and any usage constraints.

Written by the indexing model from the issue text.