Source: http://www.google.com/patents/US8006086?dq=patent:4807115
Timestamp: 2015-07-30 15:44:20
Document Index: 640146166

Matched Legal Cases: ['Application No. 60', 'arty 110', 'arty 110', 'arty 110', 'arty 110', 'arty 110', 'Application No. 2007', 'Application No. 2001', 'Application No. 2007']

Patent US8006086 - Revocation of cryptographic digital certificates - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA computer system (110) provides validity status proofs each of which proves the validity or invalidity of a set (F) of one or more digital certificates (104). The computer system may decide to cache a validity proof for a set F to later provide the cached proof to other parties. The caching decision...http://www.google.com/patents/US8006086?utm_source=gb-gplus-sharePatent US8006086 - Revocation of cryptographic digital certificatesAdvanced Patent SearchPublication numberUS8006086 B2Publication typeGrantApplication numberUS 12/492,898Publication dateAug 23, 2011Filing dateJun 26, 2009Priority dateAug 31, 2004Fee statusPaidAlso published asEP1784943A2, EP1784943A4, US7814314, US8024562, US8156327, US8209531, US20060059333, US20090259843, US20090265547, US20090265548, US20090287924, US20100287370, WO2006026737A2, WO2006026737A3Publication number12492898, 492898, US 8006086 B2, US 8006086B2, US-B2-8006086, US8006086 B2, US8006086B2InventorsCraig B. Gentry, Zulfikar Amin Ramzan, Bernhard BruhnOriginal AssigneeNtt Docomo, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (47), Non-Patent Citations (51), Classifications (12), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetRevocation of cryptographic digital certificates
US 8006086 B2Abstract
A computer system (110) provides validity status proofs each of which proves the validity or invalidity of a set (F) of one or more digital certificates (104). The computer system may decide to cache a validity proof for a set F to later provide the cached proof to other parties. The caching decision is based on the caching priority of the set F. The priority may depend on the number of certificates in the set F, the sum of the remaining validity periods for the certificates in the set, and other factors.
The present application is a divisional of U.S. patent application Ser. No. 11/218,093, filed Aug. 31, 2005, which claims priority of U.S. Provisional Application No. 60/606,213 filed on Aug. 31, 2004, both of which are incorporated herein by reference.
f: {0,1}n→{0,1}n where {0,1}n is the set of all binary strings of a length n. Let fi denote the f-fold composition; that is, fi(x)=x for i=0, and fi(x)=fi(fi-1(x)) for i>0. Let f be one-way, i.e. given f(x) where x is randomly chosen, it is hard (infeasible) to find a pre-image z such that f(z)=f(x), except with negligible probability. “Infeasible” means that given a security parameter k (e.g. k=n), the pre-image z cannot be computed in a time equal to a predefined polynomial in k except with negligible probability. Let us assume moreover that f is one-way on its iterates, i.e. for any i, given y=fi(x), it is infeasible to find z such that f(z)=y.
We will use the following notation. We let DS=(KG, Sign, Vf) denote a digital signature scheme. Here KG denotes a key generation algorithm, Sign(Sk, M) denotes the signing algorithm which outputs a signature σ on a message M under a signing key Sk. Vf(Pk, M, σ) denotes the verification algorithm which evaluates to a binary value indicating whether or not the signature σ on the message M is correct with respect to a public key Pk. We let {0,1}* denote the set of all bit strings. |s| denotes the length of a bit string s. We let H denote a cryptographic compression function that takes as input a b-bit payload and a v-bit initialization vector IV and produces a v-bit output. In some embodiments, b≧2v. We will assume that the cryptographic compression functions mentioned below can be collision resistant, i.e. it is difficult to find two distinct inputs m1≠m2 such that H(IV,m1)=H(IV,m2). We will assume that IV is fixed and publicly known, and we will sometimes omit it for notational simplicity. Practical examples of such cryptographic compression functions are SHA-1 [26] (output size is 20 bytes) and MD5 [28] (output size 16 bytes), both having a 64-byte payload. For simplicity, we will use the term “hash function” instead of compression function. The term “hash function” can also denote a mapping form {0,1}* into {0,1}v for some fixed v. Hash functions are typically one way and collision resistant, but the invention is not limited to such functions.
CoNodes(v)=�(empty set) if v is the root; (4)
Sib(v) U CoNodes(Parent(v)) otherwise.
In some embodiments, the hash chains (1) are replaced with hash trees 1210 (FIGS. 12-14). See e.g. reference [24] and PCT publication WO 2005/029445 published on 31 Mar. 2005, both incorporated herein by reference. In FIG. 12, leafs v15-v22 are each associated with a time period pi. There are eight consecutive periods p1-p8 in this example. For instance, a certificate can be valid for eight days, and each period p1 through p8 can be one day. Let gv(i) denote the node corresponding to the period pi. Thus, gv(1)=v15, gv(2)=v16, etc. These nodes will be called “grey” nodes herein. Each grey node gv(i) is a single child of a respective parent v7-v14. Above the leaf level v5-v22, the tree 1210 is a balanced binary tree.
Certificate owner system 110.1 provides the validity proof 1810 to party (computer system) 110.2 together with the certificate 104. According to some aspects of the present invention, the party 110.1 redacts the certificate by deleting the unneeded targets to reduce the amount of data provided to party 110.2. The redacted certificate 104R includes a signature proof 104R-SigCA to allow the party 110.2 to verify the CA's signature on the certificate. Party 110.1 does not have the CA's secret key. CA 120 uses a redactable signature scheme to enable the party 110.1 to provide the signature proof 104T-SigCA. Suitable redactable signature schemes are described in [12], and other schemes may be suitable, whether known or to be invented. One scheme is illustrated in FIG. 19. It is built on top of another signature scheme Sig0, which can be any signature scheme, redactable or not. To form a redactable signature on a message x, the message is broken up into blocks x0, x1, . . . (eight blocks in FIG. 19). Each of these blocks can be deleted to redact the message. If the message x is a certificate 104, one block can be standard data 104D, and each of the other blocks can consist of one or more of the targets Tar-j. Alternatively, data 104D may correspond to a number of blocks, and so can each target. A binary tree 1910 is constructed having at least as many leafs as there are blocks in the message x. For convenience of reference, the tree's nodes are labeled with binary strings as follows. The root node is labeled with the empty string E. The root's left and right children are labeled with strings ‘0’ and ‘1’ respectively. In general, for a node labeled with a string s, the left child is labeled s0 (appending 0) and the right child is labeled s1.
[1] W. Aiello, S. Lodha, and R. Ostrovsky. Fast digital identity revocation. In Proc. of CRYPTO '98, 1998. [2] G. Ateniese, J. Camenisch, M. Joye, and G. Tsudik. A Practical and Provably Secure Coalition-Resistant Group Signature Scheme. In Proceedings of CRYPTO 2000, 2000. [3] M. Bellare and P. Rogaway. Random oracles are practical: A paradigm for designing efficient protocols. In Proc. First Annual Conference on Computer and Communications Security, ACM, 1993. [4] D. Boneh, B. Lynn, and H. Shacham. Short signatures from the Weil pairing. In Proceedings of Asiacrypt '01, 2001. [5] F. Elwailly and Z. Ramzan. QuasiModo: More Efficient Hash Tree-Based Certificate Revocation. Manuscript, 2003. [6] Gassko, P. S. Gemmell, and P. MacKenzie. Efficient and fresh certification. In Proceedings of PKC 2000, 2000. [7] S. Goldwasser, S. Micali, and R. L. Rivest. A Digital Signature Scheme Secure Against Adaptive Chosen-Message Attacks. SIAM Journal on Computing, 17(2):281-308, 1988. [8] Y-C. Hu, A. Perrig, and D. Johnson. Efficient security mechanisms for routing protocols. In proceedings of the 10th Annual Network and Distributed System Security Symposium (NDSS), 2003. [9] M. Jakobsson, J-P.Hubaux, and L. Buttyan. A micropayment scheme encouraging collaboration in multi-hop cellular networks. In Proceedings of the 7th International Conference on Financial Cryptography, 2003. [10] M. Jakobsson, T. Leighton, S. Micali, and M. Szydlo. Fractal merkle tree representation and traversal. In Proceedings of the Cryptographer's Track, RSA Conference., 2003. [11] S. Jarecki and A. Odlyzko. An efficient micropayment system based on probabilistic polling. In Proceedings of the 1st International Conference on Financial Cryptography, 1997. [12] Robert Johnson, David Molnar, Dawn Xiaodong Song, and David Wagner. Homomorphic signature schemes. In CT-RSA, pages 244-262, 2002. [13] C. Jutla and M. Yung. PayTree: Amortized signatures for flexible micropayments. In Proceedings of the second USENIX workshop on electronic commerce, 1996. [14] S. Kim and H. Oh. An atomic micropayment system for a mobile computing environment. IEICE Transactions of Information and Systems, E84-D(6):709-716, 2001. [15] P. Kocher. On Certificate Revocation and Validation. In Proceedings of the 2nd International Conference on Financial Cryptography, 1998. [16] Satoshi Koga and Kouichi Sakurai. A distributed certificate status protocol with single public key. In Proceedings of PKC 2004, pages 389-401, 2004. [17] R. J. Lipton and R. Ostrovsky. Micro-Payments via Efficient Coin Flipping. In Proceedings of the 2nd International Conference on Financial Cryptography, 1998. [18] A. Malpani, R. Housely, and T. Freeman. Simple Certificate Validation Protocol-(SCVP). In IETF Draft-draft-ietf-pkix-scvp-12.txt, June 2003. [19] R. C. Merkle. Protocols for Public-Key Cryptography. In IEEE Symposium on Security and Privacy, 1980. [20] S. Micali. Efficient Certificate Revocation. MIT/LCS/TM 542b, Massachusetts Institute of Technology, 1996. [21] S. Micali. Efficient Certificate Revocation. In Proceedings of the RSA Data Security Conference, 1997. Also U.S. Pat. No. 5,666,416. [22] S. Micali. NOVOMODO: scalable certificate validation and simplified PKI management. In Proceedings of the 1st Annual PKI Research Workshop, 2002. [23] M. Myers, R. Ankney, A. Malpani, S. Galperin, and C. Adams. X.509 internet public key infrastructure Online Certificate Status Protocol—OCSP. In Internet RFC 2560, June 1999. [24] M. Naor and K. Nissim. Certificate Revocation and Certificate Update. In Proceedings of USENIX Security, 1998. [25] National Bureau of Standards. NBS FIPS PUB 81: DES modes of operation. 1980. [26] National Institute of Standards. FIPS 180-1: Secure hash standard. 1995. [27] M. Pierce and D. O'Mahony. Micropayments for Mobile Networks. In Proceedings of European Wireless, 1999. Winner of Best Paper Award. [28] R. L. Rivest. The MD5 message digest algorithm. In Internet RFC 1321, April 1992. [29] R. L. Rivest. Electronic Lottery Tickets as Micropayments. In Proceedings of the 2nd International Conference on Financial Cryptography, 1997. [30] R. L. Rivest and A. Shamir. PayWord and MicroMint—Two Simple Micropayment Schemes. CryptoBytes (RSA Laboratories), 2(1), 1996. Proceedings of 1996 International Workshop on Security Protocols. [31] R. L. Rivest, A. Shamir, and L. Adleman. A Method for Obtaining Digital Signatures and Public-Key Cryptosystems. Communications of the ACM, 21:120-126, 1978. [32] Ron Steinfeld, Laurence Bull, and Yuliang Zheng. Content extraction signatures. In Proceedings of the 4th International Conference Seoul on Information Security and Cryptology, pages 285-304. Springer-Verlag, 2002. [33] H. Tewari and D. O'Mahony. Multiparty Micropayments for Ad-Hoc Networks. In Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC), 2003. [34] H. Tewari and D. O'Mahony. Real-Time Payments for Mobile IP. IEEE Communications, 41(2): 126-136, 2003. [35] D. Wheeler. Transactions Using Bets. In Proceedings of Fourth Cambridge Workshop on Security Protocols, 1996. [36] Zhou and K-Y. Lam. Undeniable Billing in Mobile Communication. In Proceedings of MOBICOM, 1998. Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5666416Nov 16, 1995Sep 9, 1997Micali; SilvioCertificate revocation systemUS5687235Oct 26, 1995Nov 11, 1997Novell, Inc.Certificate revocation performance optimizationUS5699431Nov 13, 1995Dec 16, 1997Northern Telecom LimitedMethod for efficient management of certificate revocation lists and update informationUS5717757Nov 19, 1996Feb 10, 1998Micali; SilvioCertificate issue listsUS5717758Dec 9, 1996Feb 10, 1998Micall; SilvioWitness-based certificate revocation systemUS5793868Nov 5, 1996Aug 11, 1998Micali; SilvioCertificate revocation systemUS5903651May 14, 1996May 11, 1999Valicert, Inc.Apparatus and method for demonstrating and confirming the status of a digital certificates and other dataUS5960083Mar 24, 1997Sep 28, 1999Micali; SilvioCertificate revocation systemUS6044462Apr 2, 1997Mar 28, 2000ArcanvsMethod and apparatus for managing key revocationUS6097811Oct 11, 1996Aug 1, 2000Micali; SilvioTree-based certificate revocation systemUS6128740Dec 8, 1997Oct 3, 2000Entrust Technologies LimitedComputer security system and method with on demand publishing of certificate revocation listsUS6141347Mar 31, 1999Oct 31, 2000Motorola, Inc.Wireless communication system incorporating multicast addressing and method for useUS6226743Jan 22, 1998May 1, 2001Yeda Research And Development Co., Ltd.Method for authentication itemUS6292893Jan 14, 2000Sep 18, 2001Silvio MicaliCertificate revocation systemUS6301659Nov 26, 1997Oct 9, 2001Silvio MicaliTree-based certificate revocation systemUS6381695Jul 14, 1998Apr 30, 2002International Business Machines CorporationEncryption system with time-dependent decryptionUS6381696Sep 22, 1998Apr 30, 2002Proofspace, Inc.Method and system for transient key digital time stampsUS6385608Nov 5, 1998May 7, 2002Mitsubishi Denki Kabushiki KaishaMethod and apparatus for discovering association rulesUS6397329Nov 20, 1998May 28, 2002Telcordia Technologies, Inc.Method for efficiently revoking digital identitiesUS6442689Jul 28, 1998Aug 27, 2002Valicert, Inc.Apparatus and method for demonstrating and confirming the status of a digital certificates and other dataUS6487658Dec 18, 1997Nov 26, 2002Corestreet Security, Ltd.Efficient certificate revocationUS6532540Jun 23, 1998Mar 11, 2003Valicert, Inc.Apparatus and method for demonstrating and confirming the status of a digital certificates and other dataUS6766450Jul 25, 2001Jul 20, 2004Corestreet, Ltd.Certificate revocation systemUS7260572Jun 2, 2003Aug 21, 2007Korea Advanced Institute Of Science And TechnologyMethod of processing query about XML data using APEXUS20010034833Dec 28, 2000Oct 25, 2001Isao YagasakiCertificating system for plurality of services and method thereofUS20020046337Sep 6, 2001Apr 18, 2002Silvio MicaliTree-based certificate revocation systemUS20020165824Mar 20, 2002Nov 7, 2002Silvio MicaliScalable certificate validation and simplified PKI managementUS20020184504Mar 26, 2001Dec 5, 2002Eric HughesCombined digital signatureUS20030217265Apr 21, 2003Nov 20, 2003Toshihisa NakanoPublic key certificate revocation list generation apparatus, revocation judgement apparatus, and authentication systemUS20030221101Mar 21, 2003Nov 27, 2003Silvio MicaliEfficient certificate revocationUS20030236976Jun 19, 2002Dec 25, 2003Microsoft CorporationEfficient membership revocation by numberUS20040049675Apr 8, 2003Mar 11, 2004Silvio MicaliPhysical access controlUS20040128504Sep 30, 2003Jul 1, 2004Tero KivinenMethod for producing certificate revocation listsUS20040148505Nov 5, 2003Jul 29, 2004General Instrument CorporationCertificate renewal in a certificate authority infrastructureUS20050053045Jul 8, 2004Mar 10, 2005Samsung Electronics Co., Ltd.Method and system for distributed certificate management in ad-hoc networksUS20050055548May 13, 2004Mar 10, 2005Silvio MicaliCertificate revocation systemUS20050081037Mar 1, 2004Apr 14, 2005Yoko KumagaiMethod and apparatus for accelerating public-key certificate validationUS20050278534 *May 27, 2004Dec 15, 2005International Business Machines CorporationMethod and system for certification path processingUS20060129803Sep 9, 2004Jun 15, 2006Gentry Craig BMethod and apparatus for efficient certificate revocationEP0932109A2Jan 21, 1999Jul 28, 1999YEDA RESEARCH &amp; DEVELOPMENT COMPANY, LTD.A method for authentification itemJP2001265216A Title not availableJP2008524931A Title not availableJPH11289329A Title not availableWO1997016905A1Nov 1, 1996May 9, 1997Silvio MicaliTree-based certificate revocation systemWO2005002944A1Jul 2, 2004Jan 13, 2005Bong-Taek KimAtps for controlling train using data communicationWO2005029445A2Sep 9, 2004Mar 31, 2005Docomo Comm Lab Usa IncMethod and apparatus for efficient certificate revocationWO2006066143A2Dec 16, 2005Jun 22, 2006Ntt Docomo IncMulti-certificate revocation using encrypted proof data for proving certificate's validity or invalidity* Cited by examinerNon-Patent CitationsReference1A. Malpani, R. Housely, and T. Freeman. Simple Certificate Validation Protocol-(SCVP). In IETF Draft-draft-ietf-pkix-scvp-12.txt, Jun. 2003.2A. Malpani, R. Housely, and T. Freeman. Simple Certificate Validation Protocol-(SCVP). In IETF Draft—draft-ietf-pkix-scvp-12.txt, Jun. 2003.3C. Jutla and M. Yung. PayTree: Amortized signatures for flexible micropayments. In Proceedings of the second USENIX workshop on electronic commerce, 1996.4D. Boneh, B. Lynn, and H. Shacham. Short signatures from the Weil pairing. In Proceedings of Asiacrypt '01, 2001.5D. Wheeler. Transactions Using Bets. In Proceedings of Fourth Cambridge Workshop on Security Protocols, 1996.6Elwailly et al., "QuasiModo: Efficient Certificate Validation and Revocation" 26 Feb. 2004, Public Key Cryptography 2004, Springer-Verlag, Berlin/Heidelberg, XP019002849, pp. 375-388.7English Language Abstract of JP Pat App No. 2001-265216, 1 page.8English Translation of Office Action dated Mar. 24, 2011 in JP Patent Application No. 2007-530381, 10 pages.9Extended European Search Report for EP 05 79 3243.6, dated Jul. 5, 2011, 8 pages.10Extended European Search Report for EP 07 11 3458.9, dated Jul. 5, 2011, 9 pages.11Extended European Search Report for EP 07 11 3461.3, dated Jul. 5, 2011, 8 pages.12F. Elwailly and Z. Ramzan. QuasiModo: More Efficient Hash Tree-Based Certificate Revocation. Manuscript, 2003.13G. Ateniese, J. Camenisch, M. Joye, and G. Tsudik. A Practical and Provably Secure Coalition-Resistant Group Signature Scheme. In Proceedings of CRYPTO 2000, 2000.14H. Tewari and D. O'Mahony. Multiparty Micropayments for Ad-Hoc Networks. In Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC), 2003.15H. Tewari and D. O'Mahony. Real-Time Payments for Mobile IP. IEEE Communications, 41(2):126-136, 2003.16I. Gassko, P. S. Gemmell, and P. MacKenzie. Efficient and fresh certification. In Proceedings of PKC 2000, 2000.17J. Zhou and K-Y. Lam. Undeniable Billing in Mobile Communication. In Proceedings of MOBICOM, 1998.18Johnson R. et al. "Homomorphic Signature Schemes" Topics in Cryptology: The Cryptographer's Track at the RSA Conference 2002, San Jose, CA USA, Feb. 18-22, 2002, Springer, Berlin Heidelburg, vol. 2271 Feb. 18, 2002, pp. 244-262.19Kikuchi et al., "Performance Evaluation of Public-Key Certificate Revocation System with Balanced Hash Tree" Parallel Processing, 1999. Proceedings. 1999 International Workshops on Aizu-Wakamatsu, Japan Sep. 21-24, 1999, Los Alamitos, CA, USA, IEEE, US, Sep. 21, 1999, pp. 204-209.20M. Bellare and P. Rogaway. Random oracles are practical: A paradigm for designing efficient protocols. In Proc. First Annual Conference on Computer and Communications Security, ACM, 1993.21M. Jakobsson, J-P.Hubaux, and L. Buttyan. A micropayment scheme encouraging collaboration in multi-hop cellular networks. In Proceedings of the 7th International Conference on Financial Cryptography, 2003.22M. Jakobsson, T. Leighton, S. Micali, and M. Szydlo. Fractal merkle tree representation and traversal. In Proceedings of the Cryptographer's Track, RSA Conference, 2003.23M. Myers, R. Ankney, A. Malpani, S. Galperin, and C. Adams. X.509 internet public key infrastructure Online Certificate Status Protocol-OCSP. In Internet RFC 2560, Jun. 1999.24M. Naor and K. Nissim. Certificate Revocation and Certificate Update. In Proceedings of USENIX Security, 1998.25M. Pierce and D. O'Mahony. Micropayments for Mobile Networks. In Proceedings of European Wireless, 1999. Winner of Best Paper Award.26Machine translation into English of Japanese Patent Application No. 2001-265216, 13 pages.27National Bureau of Standards. NBS FIPS PUB 81: DES modes of operation. 1980.28National Institute of Standards. FIPS 180-1: Secure hash standard. 1995.29Office Action dated Mar. 24, 2011 in JP Patent Application No. 2007-530381, 7 pages.30Office Action dated Oct. 7, 2010 in U.S. Appl. No. 12/492,901, 19 pages.31Office Action dated Sep. 3, 2010 in U.S. Appl. No. 12/840,437, 14 pages.32P. Kocher. On Certificate Revocation and Validation. In Proceedings of the 2nd International Conference on Financial Cryptography, 1998.33R. C. Merkle. Protocols for Public-Key Cryptography. In IEEE Symposium on Security and Privacy, 1980.34R. J. Lipton and R. Ostrovsky. Micro-Payments via Efficient Coin Flipping. In Proceedings of the 2nd International Conference on Financial Cryptography, 1998.35R. Steinfeld, L. Bull, Y. Zheng "Content Extraction Signatures" Lecture Notes in Computer Science, vol. 2288/2002, Springer Berlin / Heidelberg, Apr. 28, 2003.36R.L. Rivest and A. Shamir. PayWord and MicroMint-Two Simple Micropayment Schemes. CryptoBytes (RSA Laboratories), 2(1), 1996. Proceedings of 1996 International Workshop on Security Protocols.37R.L. Rivest and A. Shamir. PayWord and MicroMint—Two Simple Micropayment Schemes. CryptoBytes (RSA Laboratories), 2(1), 1996. Proceedings of 1996 International Workshop on Security Protocols.38R.L. Rivest, A. Shamir, and L. Adleman. A Method for Obtaining Digital Signatures and Public-Key Cryptosystems. Communications of the ACM, 21:120-126, 1978.39R.L. Rivest. Electronic Lottery Tickets as Micropayments. In Proceedings of the 2nd International Conference on Financial Cryptography, 1997.40R.L. Rivest. The MD5 message digest algorithm. In Internet RFC 1321, Apr. 1992.41Robert Johnson, David Molnar, Dawn Xiaodong Song, and David Wagner. Homomorphic signature schemes. In CT-RSA, pp. 244-262, 2002.42Ron Steinfeld, Laurence Bull, and Yuliang Zheng. Content extraction signatures. In Proceedings of the 4th International Conference Seoul on Information Security and Cryptology, pp. 285-304. Springer-Verlag, 2002.43S. Goldwasser, S. Micali, and R. L. Rivest. A Digital Signature Scheme Secure Against Adaptive Chosen-Message Attacks. SIAM Journal on Computing, 17(2):281-308, 1988.44S. Jarecki and A. Odlyzko. An efficient micropayment system based on probabilistic polling. In Proceedings of the 1st International Conference on Financial Cryptography, 1997.45S. Kim and H. Oh. An atomic micropayment system for a mobile computing environment. IEICE Transactions of Information and Systems, E84-D(6):709-716, 2001.46S. Micali. Efficient Certificate Revocation. In Proceedings of the RSA Data Security Conference, 1997. Also U.S. Patent No. 5,666,416.47S. Micali. Efficient Certificate Revocation. MIT/LCS/TM 542b, Massachusetts Institute of Technology, 1996.48S. Micali. NOVOMODO: scalable certificate validation and simplified PKI management. In Proceedings of the 1st Annual PKI Research Workshop, 2002.49Satoshi Koga and Kouichi Sakurai. A distributed certificate status protocol with single public key. In Proceedings of PKC 2004, pp. 389-401, 2004.50W. Aiello, S. Lodha, and R. Ostrovsky. Fast digital identity revocation. In Proc. of CRYPTO '98, 1998.51Y-C. Hu, A. Perrig, and D. Johnson. Efficient security mechanisms for routing protocols. In proceedings of the 10th Annual Network and Distributed System Security Symposium (NDSS), 2003.Classifications U.S. Classification713/158, 713/175International ClassificationH04L29/06Cooperative ClassificationH04L2209/38, H04L9/3236, H04L2209/56, H04L9/3265, H04L63/0823, H04L2209/80European ClassificationH04L63/08C, H04L9/32Q2, H04L9/32LLegal EventsDateCodeEventDescriptionFeb 11, 2015FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services