[Logic layer] Signature can not be saved to the database yet

[Extiriority]

Describe the bug
The signature library has been implemented but the logic is not finished.

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.