How to organize the signature of a document using SMS?

Question

Software design

There is a task in which they ask to make a simple electronic signature (SES), lawyers confirmed that the signature of a document in the user's personal account using an SMS code is legally binding in their case.

Now the question is - how to store the generated SMS codes in the database? And can they be stored there? Or do you need to store the hash of this SMS in the database and compare the hashes when signing the document?

Maybe someone knows how banks store SMS passwords in their databases and how the process of confirming transactions works for them?

Answer 1

1. Clarify with lawyers what kind of data they need for litigation in problematic cases.
2. Fix the fact that the code was sent to the user via SMS and the fact that the user entered the codes, plus add requirements from lawyers to this.
About SMS code and hash, in fact, there will be a code of 4-8 characters, or rather even numbers, so it is problematic to make a hash without collisions from this, so most likely it just corresponds to the document-code entry in the database.