Social Circles: Tackling Privacy in Social Networks (2009)
Users of social-networking services share an abundance of personal information with a large number of “friends. ” Services such as Facebook have recognized the need for privacy mechanisms that...
Combating Spam and Denial-of-Service Attacks with Trusted Puzzle Solvers ⋆ (2008)
Patrick P. Tsang, Sean W. Smith
Abstract. Cryptographic puzzles can be used to mitigate spam and denial-of-service (DoS) attacks, as well as to implement timed-release cryptography. However, existing crypto puzzles are impractical...
Secure Cryptographic Precomputation with Insecure Memory ⋆ (2008)
Patrick P. Tsang, Sean W. Smith
Abstract. We propose a solution that provides secure storage for cryptographic precomputation using only insecure memory that is susceptible to eavesdropping and tampering. Specifically, we design a...
Recoverable and Untraceable E-Cash (2008)
Joseph K. Liu, Patrick P. Tsang, Duncan S. Wong
Abstract. In an electronic cash (e-cash) system, Recoverability means once you have lost your e-cash, you still can get back the amount of e-cash that you have lost. Untraceability means no one can...
Efficient Verifiable Ring Encryption for Ad Hoc Groups (2008)
Joseph K. Liu, Patrick P. Tsang, Duncan S. Wong
Abstract. We propose an efficient Verifiable Ring Encryption (VRE) for ad hoc groups. VRE is a kind of verifiable encryption [16,1,4,2,8] in which it can be publicly verified that there exists at...
Batch Pairing Delegation ⋆ (2008)
Patrick P. Tsang, Sean W. Smith
Abstract. Pairing-based cryptography (PBC) has enabled the construction of many cryptographic protocols. However, there are scenarios when PBC is too heavyweight to use, such as when the computing...
Nymble: Blocking Misbehaving Users in Anonymizing Networks ∗† (2008)
Patrick P. Tsang, Apu Kapadia, Cory Cornelius, Sean W. Smith
Anonymizing networks such as Tor allow users to access Internet services privately by using a series of routers to hide the client’s IP address from the server. The success of such networks,...
BLAC: Revoking Repeatedly Misbehaving Anonymous Users Without Relying on TTPs ∗ (2008)
Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith
Several credential systems have been proposed in which users can authenticate to service providers anonymously. Since anonymity can give users the license to misbehave, some variants allow the...
Patrick P. Tsang, Sean W. Smith
Abstract We construct a bump-in-the-wire (BITW) solution that retrofits security into time-critical communications over bandwidth-limited serial links between devices in legacy Supervisory Control...
YASIR: A Low-Latency, High-Integrity Security Retrofit for Legacy SCADA Systems ∗ (2007)
Patrick P. Tsang, Sean W. Smith
We construct a bump-in-the-wire (BITW) solution that retrofits security into time-critical communications over bandwidth-limited serial links between devices in Supervisory Control And Data...
Attribute-based publishing with hidden credentials and hidden policies (2007)
Apu Kapadia, Patrick P. Tsang, Sean W. Smith
With Hidden Credentials Alice can send policyencrypted data to Bob in such a way that he can decrypt the data only with the right combination of credentials. Alice gains no knowledge of Bob’s...
Blacklistable anonymous credentials: Blocking misbehaving users without TTPs (2007)
Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith
Several credential systems have been proposed in which users can authenticate to services anonymously. Since anonymity can give users the license to misbehave, some variants allow the selective...
Nymble: Anonymous IP-address blocking (2007)
Peter C. Johnson, Apu Kapadia, Patrick P. Tsang, Sean W. Smith
Abstract. Anonymizing networks such as Tor allow users to access Internet services privately using a series of routers to hide the client’s IP address from the server. Tor’s success, however, has...
Nymble: Anonymous IP-address blocking (2007)
Peter C. Johnson, Apu Kapadia, Patrick P. Tsang, Sean W. Smith
Abstract. Anonymizing networks such as Tor allow users to access Internet services privately using a series of routers to hide the client’s IP address from the server. Tor’s success, however, has...
Blacklistable anonymous credentials: Blocking misbehaving users without TTPs (2007)
Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith
Several credential systems have been proposed in which users can authenticate to services anonymously. Since anonymity can give users the license to misbehave, some variants allow the selective...
Nymble: Anonymous IP-address blocking (2007)
Peter C. Johnson, Apu Kapadia, Patrick P. Tsang, Sean W. Smith
Abstract. Anonymizing networks such as Tor allow users to access Internet services privately using a series of routers to hide the client’s IP address from the server. Tor’s success, however, has...
Blacklistable anonymous credentials: Blocking misbehaving users without TTPs (2007)
Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith
Several credential systems have been proposed in which users can authenticate to services anonymously. Since anonymity can give users the license to misbehave, some variants allow the selective...
Secure Cryptographic Precomputation with Insecure Memory (2007)
Patrick P. Tsang, Sean W. Smith
Precomputation dramatically reduces the execution latency of many cryptographic algorithms. To sustain the reduced latency over time during which these algorithms are routinely invoked, however, a...
Blacklistable anonymous credentials: Blocking misbehaving users without TTPs (2007)
Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith
Several credential systems have been proposed in which users can authenticate to services anonymously. Since anonymity can give users the license to misbehave, some variants allow the selective...
Attribute-based publishing with hidden credentials and hidden policies (2007)
Apu Kapadia, Patrick P. Tsang, Sean W. Smith
With Hidden Credentials Alice can send policyencrypted data to Bob in such a way that he can decrypt the data only with the right combination of credentials. Alice gains no knowledge of Bob’s...
Anonymous IP-address blocking in tor with trusted computing (work-in-progress (2006)
Patrick P. Tsang, Apu Kapadia, Sean W. Smith
How does one block an anonymous user hiding behind an anonymous routing network? In this paper, we outline a security protocol that uses resourceconstrained trusted hardware to facilitate anonymous...
Universal custodian-hiding verifiable encryption for discrete logarithms (2006)
Joseph K. Liu, Patrick P. Tsang, Duncan S. Wong, Robertw. Zhu
Abstract. We introduce the notion of Universal Custodian-Hiding Verifiable Encryption (UCH-VE) and propose a scheme of this type for discrete logarithms. A UCH-VE scheme allows an encryptor to...
A Suite of ID-Based Threshold Ring Signature Schemes with Different Levels of Anonymity (2005)
Man Ho Au, Man Ho Au, Joseph K. Liu, Joseph K. Liu, Patrick P. Tsang, Patrick P. Tsang, ...
Since the introduction of Identity-based (ID-based) cryptography by Shamir in 1984, numerous ID-based signature schemes have been proposed. In 2001, Rivest et al. introduced ring signature that...
Short linkable ring signatures for e-voting, e-cash and attestation (2005)
Patrick P. Tsang, Victor K. Wei
Abstract. A ring signature scheme can be viewed as a group signature scheme with no anonymity revocation and with simple group setup. A linkable ring signature (LRS) scheme additionally allows anyone...
Short linkable ring signatures for e-voting, e-cash and attestation (2005)
Patrick P. Tsang, Victor K. Wei
Abstract. A ring signature scheme can be viewed as a group signature scheme with no anonymity revocation and with simple group setup. A linkable ring signature (LRS) scheme additionally allows anyone...
PEREA: Towards practical TTP-free revocation in anonymous authentication (2005)
Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith
Several anonymous authentication schemes allow servers to revoke a misbehaving user’s ability to make future accesses. Traditionally, these schemes have relied on powerful TTPs capable of...
PEREA: Towards practical TTP-free revocation in anonymous authentication (2005)
Patrick P. Tsang, Man Ho Au, Apu Kapadia, Sean W. Smith
Several anonymous authentication schemes allow servers to revoke a misbehaving user’s ability to make future accesses. Traditionally, these schemes have relied on powerful TTPs capable of...
Separable linkable threshold ring signatures (2004)
Patrick P. Tsang, Victor K. Wei, Tony K. Chan, Man Ho Au, Joseph K. Liu, Duncan S. Wong
Abstract. A ring signature scheme is a group signature scheme with no group manager to setup a group or revoke a signer. A linkable ring signature, introduced by Liu, et al. [20], additionally allows...
Short Linkable Ring Signatures for E-voting, E-cash and Attestation (2004)
Patrick P. Tsang, Victor K. Wei
A ring signature scheme can be viewed as a group signature scheme with no anonymity revocation and with simple group setup.
Separable Linkable Threshold Ring Signatures (2004)
Patrick P. Tsang, Victor K. Wei, Tony K. Chan, Man Ho Au, Joseph K. Liu, Duncan S. Wong
A ring signature scheme is a group signature scheme with no group manager to setup a group or revoke a signer. A linkable ring signature, introduced by Liu, et al. [20], additionally allows anyone to...
Separable linkable threshold ring signatures (2004)
Patrick P. Tsang, Victor K. Wei, Tony K. Chan, Man Ho Au, Joseph K, Duncan S. Wong
Abstract. A ring signature scheme is a group signature scheme with no group manager to setup a group or revoke a signer. A linkable ring signature, introduced by Liu, et al. [20], additionally allows...
YASIR: A Low-Latency, High-Integrity Security Retrofit for Legacy SCADA Systems (1970)
Patrick P. Tsang, Sean W. Smith
We construct a bump-in-the-wire (BITW) solution that retrofits security into time-critical communications over bandwidth-limited serial links between devices in legacy Supervisory Control And Data...