Optimized Public Key Infrastructure - A PKI to Support Efficient Document's Signatures

Optimized Public Key Infrastructures are traditional PKI in which end users may optimize the signatures of their documents, replacing the signer’s validation data with Optimized Certificates (OC). OCs carry the signer’s identification and public key, but are issued for a specific time, i.e., fields notBefore and notAfter have the same value, thus there are no reasons to revoke them. The OC’s certification path is supposed to be shorter and uses Micali’s revocation scheme. Furthermore, OCs include signed document’s hashcodes, working also as time-stamps. Therefore, OCs are useful to replace signed document’s validation data by one smaller and easier to verify. Finally, when OCs become invalid due to cryptographic algorithm weakness and limits in the validity periods of their certificate chains, they can be easily replaced by new ones, thus this proposal is suitable for efficient long term archiving.