Give every unique value in column a unique value

I am trying to figure out the best way to assign a unique, human readable code to each record having a unique entry in a particular field.

In my primary table every record represents a Document and the information in each record is extracted from or associated with it, including its MD5 hash (i.e., a unique 32 character algorithmically generated alphanumeric code).

The records in the database were created by identifying individual Documents contained within a File and creating a new record for every Document. So, e.g., a single PDF File might have 5 separate Documents contained within it, and thus 5 different Airtable records.

Every File has a unique MDF Hash value. Every Document within that file has the same MD5 Hash (since the value is calculated based on the File, not the Document).

So, I want to create the equivalent of a File ID # by giving each unique MD5 Hash a unique sequential value, and then associated that value with each corresponding record.

Thoughts on the best approach to this? Thanks.