A key escrow system with warrant bounds

We propose a key escrow system that permits warrants for the interception and decryption of communications for arbitrary time periods, and with either one or two communicating parties specified as the target. The system is simple and practical, and affords reasonable protection against misuse. We argue that use of such a system can produce both greater privacy protection and more effective law enforcement than we now enjo

Crumpled and Abraded Encryption: Implementation and Provably Secure Construction

Abraded and crumpled encryption allows communication software such as messaging platforms to ensure privacy for their users while still allowing for some investigation by law enforcement. Crumpled encryption ensures that each decryption is costly and prevents law enforcement from performing mass decryption of messages. Abrasion ensures that only large organizations like law enforcement are able to access any messages. The current abrasion construction uses public key parameters such as prime numbers which makes the abrasion scheme difficult to analyze and allows possible backdoors. In this thesis, we introduce a new abrasion construction which uses hash functions to avoid the problems with the current abrasion construction. In addition, we present a proof-of-concept for using crumpled encryption on an email server

Real Estate Trends: Title and Blockchain Technology

This article discusses how blockchain technology could revolutionize real property title record-keeping, or not. It begins with a brief history of property transfers and title registry in the United States, followed by a basic overview of blockchain technology. Then it outlines how title is typically recorded today, including the role of traditional grantor-grantee indexes, plus less common tract indexes. It describes common title problems, often caused by human error, and exacerbated by an outdated system, together with an explanation of how blockchain and even tract indexes could eliminate or mitigate many title problems and simplify an antiquated system. The article shares various agencies’ studies and experiences using blockchain for land transfers or title registry, and lessons learned. That leads to a broader discussion of blockchain benefits and drawbacks for title registries. It concludes that the costs associated with making a wholesale transition to blockchain does not presently justify such transition, even though blockchain has the potential to simplify indexing, enhance security, and reduce title errors. However, many problems could be avoided or resolved through uniform adoption of tract indexes which would require universal adoption of e-recording and digital documents

Imbalanced Cryptographic Protocols

Efficiency is paramount when designing cryptographic protocols, heavy mathematical operations often increase computation time, even for modern computers. Moreover, they produce large amounts of data that need to be sent through (often limited) network connections. Therefore, many research efforts are invested in improving efficiency, sometimes leading to imbalanced cryptographic protocols. We define three types of imbalanced protocols, computationally, communicationally, and functionally imbalanced protocols. Computationally imbalanced cryptographic protocols appear when optimizing a protocol for one party having significantly more computing power. In communicationally imbalanced cryptographic protocols the messages mainly flow from one party to the others. Finally, in functionally imbalanced cryptographic protocols the functional requirements of one party strongly differ from the other parties. We start our study by looking into laconic cryptography, which fits both the computational and communicational category. The emerging area of laconic cryptography involves the design of two-party protocols involving a sender and a receiver, where the receiver’s input is large. The key efficiency requirement is that the protocol communication complexity must be independent of the receiver’s input size. We show a new way to build laconic OT based on the new notion of Set Membership Encryption (SME) – a new member in the area of laconic cryptography. SME allows a sender to encrypt to one recipient from a universe of receivers, while using a small digest from a large subset of receivers. A recipient is only able to decrypt the message if and only if it is part of the large subset. As another example of a communicationally imbalanced protocol we will look at NIZKs. We consider the problem of proving in zero-knowledge the existence of exploits in executables compiled to run on real-world processors. Finally, we investigate the problem of constructing law enforcement access systems that mitigate the possibility of unauthorized surveillance, as a functionally imbalanced cryptographic protocol. We present two main constructions. The first construction enables prospective access, allowing surveillance only if encryption occurs after a warrant has been issued and activated. The second allows retrospective access to communications that occurred prior to a warrant’s issuance