Fuente: Wipo "digitalization" A server can record (i) a first digital signature algorithm with a first certificate, and a corresponding first private key, and (ii) a second digital signature algorithm with a second certificate, and a corresponding second private key. The server can select first data to sign for the first algorithm and the first private key in order to generate a first digital signature. The server can select second data to sign, wherein the second data to sign includes at least the first digital signature. The server can generate a second digital signature for the second data to sign using the second algorithm and the second private key. The server can transmit a message comprising (i) the first and second certificates, and (ii) the first and second digital signatures to a client device. Systems and methods can concurrently support the use of both post-quantum and classical cryptography to enhance security.