What are the issues involved in replacing handwritten signatures with digital signatures in practice? Or a step further, could we use digital signatures to replace all authentication-based systems? E.g. issue banknotes using a digital signature so that there would be no paper-based money in future.

What are the different security assumptions for the RSA-signature scheme and DSA?

Are these assumptions comparable? If not, which one is better and why?

What are the advantages and disadvantages of RSA and DSA respectively?

Where are digital signatures mainly used in our daily life?