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64
Certificate Revocation and Certificate Update
 USENIX SECURITY SYMPOSIUM
, 1998
"... A new solution is suggested for the problem of certificate revocation. This solution represents Certificate Revocation Lists by an authenticated search data structure. The process of verifying whether a certificate is in the list or not, as well as updating the list, is made very efficient. The sugg ..."
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Cited by 144 (0 self)
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A new solution is suggested for the problem of certificate revocation. This solution represents Certificate Revocation Lists by an authenticated search data structure. The process of verifying whether a certificate is in the list or not, as well as updating the list, is made very efficient. The suggested solution gains in scalability, communication costs, robustness to parameter changes and update rate. Comparisons to the following solutions are included: 'traditional' CRLs (Certificate Revocation Lists), Micali's Certificate Revocation System (CRS) and Kocher's Certificate Revocation Trees (CRT).
Finally, a scenario in which certificates are not revoked, but frequently issued for shortterm periods is considered. Based on the authenticated search data structure scheme, a certificate update scheme is presented in which all certificates are updated by a common message.
The suggested solutions for certificate revocation and certificate update problems is better than current solutions with respect to communication costs, update rate, and robustness to changes in parameters and is compatible e.g. with X.500 certificates.
On the Construction of PseudoRandom Permutations: LubyRackoff Revisited
 JOURNAL OF CRYPTOLOGY
, 1997
"... Luby and Rackoff [27] showed a method for constructing a pseudorandom permutation from a pseudorandom function. The method is based on composing four (or three for weakened security) so called Feistel permutations, each of which requires the evaluation of a pseudorandom function. We reduce somewh ..."
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Cited by 94 (8 self)
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Luby and Rackoff [27] showed a method for constructing a pseudorandom permutation from a pseudorandom function. The method is based on composing four (or three for weakened security) so called Feistel permutations, each of which requires the evaluation of a pseudorandom function. We reduce somewhat the complexity of the construction and simplify its proof of security by showing that two Feistel permutations are sufficient together with initial and final pairwise independent permutations. The revised construction and proof provide a framework in which similar constructions may be brought up and their security can be easily proved. We demonstrate this by presenting some additional adjustments of the construction that achieve the following:  Reduce the success probability of the adversary.  Provide a construction of pseudorandom permutations with large input size using pseudorandom functions with small input size.
Onthefly verification of rateless erasure codes for efficient content distribution
 In Proceedings of the IEEE Symposium on Security and Privacy
, 2004
"... Abstract — The quality of peertopeer content distribution can suffer when malicious participants intentionally corrupt content. Some systems using simple blockbyblock downloading can verify blocks with traditional cryptographic signatures and hashes, but these techniques do not apply well to mor ..."
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Cited by 91 (4 self)
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Abstract — The quality of peertopeer content distribution can suffer when malicious participants intentionally corrupt content. Some systems using simple blockbyblock downloading can verify blocks with traditional cryptographic signatures and hashes, but these techniques do not apply well to more elegant systems that use rateless erasure codes for efficient multicast transfers. This paper presents a practical scheme, based on homomorphic hashing, that enables a downloader to perform onthefly verification of erasureencoded blocks. I.
A new paradigm for collisionfree hashing: incrementality at reduced cost
 In Eurocrypt97
, 1997
"... We present a simple, new paradigm for the design of collisionfree hash functions. Any function emanating from this paradigm is incremental. (This means that if a message x which Ihave previously hashed is modi ed to x 0 then rather than having to recompute the hash of x 0 from scratch, I can quick ..."
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Cited by 81 (2 self)
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We present a simple, new paradigm for the design of collisionfree hash functions. Any function emanating from this paradigm is incremental. (This means that if a message x which Ihave previously hashed is modi ed to x 0 then rather than having to recompute the hash of x 0 from scratch, I can quickly \update " the old hash value to the new one, in time proportional to the amount of modi cation made in x to get x 0.) Also any function emanating from this paradigm is parallelizable, useful for hardware implementation. We derive several speci c functions from our paradigm. All use a standard hash function, assumed ideal, and some algebraic operations. The rst function, MuHASH, uses one modular multiplication per block of the message, making it reasonably e cient, and signi cantly faster than previous incremental hash functions. Its security is proven, based on the hardness of the discrete logarithm problem. A second function, AdHASH, is even faster, using additions instead of multiplications, with security proven given either that approximation of the length of shortest lattice vectors is hard or that the weighted subset sum problem is hard. A third function, LtHASH, is a practical variant of recent lattice based functions, with security proven
Homomorphic Signature Schemes
"... Privacy homomorphisms, encryption schemes that are also homomorphisms relative to some binary operation, have been studied for some time, but one may also consider the analogous problem of homomorphic signature schemes. In this paper we introduce basic definitions of security for homomorphic signa ..."
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Cited by 71 (2 self)
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Privacy homomorphisms, encryption schemes that are also homomorphisms relative to some binary operation, have been studied for some time, but one may also consider the analogous problem of homomorphic signature schemes. In this paper we introduce basic definitions of security for homomorphic signature systems, motivate the inquiry with example applications, and describe several schemes that are homomorphic with respect to useful binary operations. In particular, we describe a scheme that allows a signature holder to construct the signature on an arbitrarily redacted submessage of the originally signed message. We present another scheme for signing sets that is homomorphic with respect to both union and taking subsets. Finally, we show that any signature scheme that is homomorphic with respect to integer addition must be insecure.
Implementation of an Authenticated Dictionary with Skip Lists and Commutative Hashing
 DARPA INFORMATION SURVIVABILITY CONFERENCE AND EXPOSITION
, 2001
"... We present the software architecture and implementation of an efficient data structure for dynamically maintaining an authenticated dictionary. The building blocks of the data structure are skip lists and oneway commutative hash functions. We also present the results of a preliminary experiment on ..."
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Cited by 68 (22 self)
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We present the software architecture and implementation of an efficient data structure for dynamically maintaining an authenticated dictionary. The building blocks of the data structure are skip lists and oneway commutative hash functions. We also present the results of a preliminary experiment on the performance of the data structure. Applications of our work include certificate revocation in public key infrastructure and the publication of data collections on the Internet.
Bucket Hashing and its Application to Fast Message Authentication
, 1995
"... We introduce a new technique for constructing a family of universal hash functions. ..."
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Cited by 51 (4 self)
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We introduce a new technique for constructing a family of universal hash functions.
Synthesizers and Their Application to the Parallel Construction of PseudoRandom Functions
, 1995
"... A pseudorandom function is a fundamental cryptographic primitive that is essential for encryption, identification and authentication. We present a new cryptographic primitive called pseudorandom synthesizer and show how to use it in order to get a parallel construction of a pseudorandom function. ..."
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Cited by 42 (11 self)
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A pseudorandom function is a fundamental cryptographic primitive that is essential for encryption, identification and authentication. We present a new cryptographic primitive called pseudorandom synthesizer and show how to use it in order to get a parallel construction of a pseudorandom function. We show several NC¹ implementations of synthesizers based on concrete intractability assumptions as factoring and the DiffieHellman assumption. This yields the first parallel pseudorandom functions (based on standard intractability assumptions) and the only alternative to the original construction of Goldreich, Goldwasser and Micali. In addition, we show parallel constructions of synthesizers based on other primitives such as weak pseudorandom functions or trapdoor oneway permutations. The security of all our constructions is similar to the security of the underlying assumptions. The connection with problems in Computational Learning Theory is discussed.
Security for a High Performance Commodity Storage Subsystem
, 1999
"... and the United States Postal Service. The views and conclusions in this document are my own and should not be interpreted as representing the official policies, either expressed or implied, of any supporting organization or the U.S. Government. ..."
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Cited by 41 (1 self)
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and the United States Postal Service. The views and conclusions in this document are my own and should not be interpreted as representing the official policies, either expressed or implied, of any supporting organization or the U.S. Government.
An Efficient Dynamic and Distributed Cryptographic Accumulator
 Tech. Rep., Johns Hopkins Information Security Institute
, 2002
"... We show how to use the RSA oneway accumulator to realize an efficient and dynamic authenticated dictionary, where untrusted directories provide cryptographically verifiable answers to membership queries on a set maintained by a trusted source. Our accumulatorbased scheme for authenticated dicti ..."
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Cited by 40 (14 self)
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We show how to use the RSA oneway accumulator to realize an efficient and dynamic authenticated dictionary, where untrusted directories provide cryptographically verifiable answers to membership queries on a set maintained by a trusted source. Our accumulatorbased scheme for authenticated dictionaries supports efficient incremental updates of the underlying set by insertions and deletions of elements. Also, the user can optimally verify in constant time the authenticity of the answer provided by a directory with a simple and practical algorithm. This work has applications to certificate management in public key infrastructure and endtoend integrity of data collections published by third parties on the Internet.