The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 10, 2012
Filed:
Jun. 26, 2009
Craig B. Gentry, Mountain View, CA (US);
Zulfikar Amin Ramzan, San Mateo, CA (US);
Bernhard Bruhn, Stuttgart, DE;
Craig B. Gentry, Mountain View, CA (US);
Zulfikar Amin Ramzan, San Mateo, CA (US);
Bernhard Bruhn, Stuttgart, DE;
NTT DoCoMo, Inc., Tokyo, JP;
Abstract
A distributed certificate authority includes a CA and a number of Sub-CAs (). The Sub-CAs have secret certificate validation data, but different data are provided to different Sub-CAs for each certificate. If a Sub-CA is compromised, the Sub-CA validity proof will be withheld by the CA to alert the verifiers not to use the data from this Sub-CA. Also, the secret data are encrypted when distributed to the Sub-CAs. A decryption key (DK.j.k) for each 'partition' of time is distributed to each Sub-CA at or shortly before the start of the partition. A compromised Sub-CA can be reactivated at the end of the partition because the adversary does not get the decryption keys for the future partitions.