RFID reader revocation checking using low power attached displays

An RFID tag comprising:

• a passively powered processing circuit for storing and communicating encrypted information;
• a portable package including the processing circuit, the package capable of being personally ported by an individual;
• a passively powered display coupled to the processing circuit and disposed on the RFID tag,
• wherein the RFID tag is in combination with a reader where the processing circuit receives from the reader a public key certificate (PKC) along with a signed and time-stamped proof of non-revocation and where the processing circuit is operable to verify the respective signatures on the reader's PKC and the non-revocation proof, and to provide on the display disposed on the RFID tag either the date reported as current by the reader or the lesser of PKC expiration time or non-revocation proof expiration time.

An RFID tag attended by an individual for use in combination with an RFID reader, the RFID tag comprising:

• a display capable of showing a date;
• a control for making the tag temporarily inaccessible to the reader;
• a calculator to calculate an expiration date of revocation status information by knowing its issuance date;
• and
• a count-down timer,
• wherein the RFID tag is in combination with a reader where the control receives from the reader a public key certificate (PKC) along with a signed and time-stamped proof of non-revocation and where the control is operable to verify the respective signatures on the reader's PKC and the non-revocation proof, and to provide on the display disposed on the RFID tag either the date reported as current by the reader or the lesser of PKC expiration time or non-revocation proof expiration time.