摘要 |
A data carrier comprising computer data for proving validity or invalidity of each of a plurality of digital certificates, each digital certificate certifying that a cryptographic key is associated with an entity, the computer data comprising defining first data and second data, wherein: the first data is for generating for each digital certificate, by a first computer system, one or more first proofs, each first proof being a proof of validity or invalidity of the digital certificate; the second data is for generating for each digital certificate, by a second computer system, one or more second proofs, each second proof being a proof of validity or invalidity of the digital certificate; wherein the first data is different from the second data, and for at least one digital certificate at least one first proof is different from each second proof and at least one second proof is different from each first proof. |