Q: I want to add timestamps when adding digital signatures to PDF documents in PDF Studio. Do you have a list of timestamp servers available?
A: In PDF Studio version 2020, we switched our algorithm for communication with timestamp servers from SHA1 to SHA512. This FreeTSA – Guide recommends using SHA-512. SHA-512 is part of SHA-2 (read more on md5hashing.net).
As of August 2020, below is the list of timestamp servers that we found working in PDF Studio 2020: