Is it possible to detect changes in the base64 encoding of an object to detect the degree of changes in the object.
Suppose I send a document attachment to several users and each makes changes to it and emails back to me, can I use the string distance between original base64 and the received base64s to detect which version has the most changes. Would that be a valid metric?
If not, would there be any other metrics to quantify the deltas?
That would depend entirely on the type of the document you had encoded. If it was a text file, then sure, the base64 encoded difference are probably on a par with the actual changes. However, you may have a format of a file where changes to the contents effectively produce a completely different binary file. An example of this would be a ZIP file.