Database entity signing

[davidgarth]

To protect sensitive data against tampering in the database directly entities should be signed when written to the database and validated on load.

[yoavamit]

@AlexSzlavik I got a working POC PR for this here: #896
Wanted to update you since I saw you are assigned to this issue.

If you'd like, you can take over my PR/assign this issue to me/pair on it together, whatever fits you best.

[yoavamit]

It's been a while... this issue will be resolve with this PR #1397