Method of issuance and revocation of certificates of authenticity used in public key networks and other systems

A method for authenticating users of a public key cryptographic system, comprising the steps of:

• issuing a signed certificate for each user of a public key cryptographic system, wherein the signed certificate contains an issue date, a unique public key associated with the user, and other public information pertaining to the user, and wherein a valid certification is one that authenticates an association between the user and the public key contained in the certificate, and an invalid certificate is one for which the association between the user and the public key is no longer valid;
• issuing a signed list of invalid certificates, referred to as a blacklist, containing a blacklist start date, a blacklist expiration date, and an entry for each user whose certificate was issued after the blacklist start date and is invalid;
• and
• determining whether a user's certificate is valid by first obtaining a copy of the certificate and a copy of the signed blacklist, then determining whether the blacklist has expired, and then, if the blacklist has not expired, determining whether the certificate issued after the blacklist start date and is not on the blacklist, and is therefore valid.

A method for authenticating users of a public key cryotpgraphic system, comprising the steps of:

• issuing a signed certificate for each user of a public key cryptographic system, wherein the signed certificate contains an issue sequence number, a unique public key associated with the user, and other public information pertaining to the user, and wherein a valid certificate is one that authenticates an association between the user and the public key contained in the certificate, and an invalid certificate is one for which the association between the user and the public key is no longer valid;
• issuing a signed list of invalid certificates, referred to as a blacklist, containing a blacklist start sequence number, a blacklist expiration date, and an entry for each user whose certificate has a sequence number greater than the blacklist start sequence number and is to be considered invalid;
• and
• determining whether a user's certificate is valid by first obtaining a copy of the certificate and a copy of the signed blacklist, then determining whether the blacklist has expired, and then, if the blacklist has not expired, determining whether the certificate has a sequence number greater than the blacklist start sequence number and is not on the blacklist, and is therefore valid.