International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Eran Tromer

Publications

Year
Venue
Title
2022
EUROCRYPT
Unclonable Polymers and Their Cryptographic Applications 📺
We propose a mechanism for generating and manipulating protein polymers to obtain a new type of *consumable storage* that exhibits intriguing cryptographic "self-destruct" properties, assuming the hardness of certain polymer-sequencing problems. To demonstrate the cryptographic potential of this technology, we first develop a formalism that captures (in a minimalistic way) the functionality and security properties provided by the technology. Next, using this technology, we construct and prove security of two cryptographic applications that are currently obtainable only via trusted hardware that implements logical circuitry (either classical or quantum). The first application is a password-controlled *secure vault* where the stored data is irrecoverably erased once a threshold of unsuccessful access attempts is reached. The second is (a somewhat relaxed version of) *one time programs*, namely a device that allows evaluating a secret function only a limited number of times before self-destructing, where each evaluation is made on a fresh user-chosen input. Finally, while our constructions, modeling, and analysis are designed to capture the proposed polymer-based technology, they are sufficiently general to be of potential independent interest.
2022
CRYPTO
Oblivious Message Retrieval
Zeyu Liu Eran Tromer
Anonymous message delivery systems, such as private messaging services and privacy-preserving payment systems, need a mechanism for recipients to retrieve the messages addressed to them, without leaking metadata or letting their messages be linked. Recipients could download all posted messages and scan for those addressed to them, but communication and computation costs are excessive at scale. We show how untrusted servers can detect messages on behalf of recipients, and summarize these into a compact encrypted digest that recipients can easily decrypt. These servers operate obliviously and do not learn anything about which messages are addressed to which recipients. Privacy, soundness, and completeness hold even if everyone but the recipient is adversarial and colluding (unlike in prior schemes). Our starting point is an asymptotically-efficient approach, using Fully Homomorphic Encryption and homomorphically-encoded Sparse Random Linear Codes. We then address the concrete performance using bespoke tailoring of lattice-based cryptographic components, alongside various algebraic and algorithmic optimizations. This reduces the digest size to a few bits per message scanned. Concretely, the servers' cost is ~$1 per million messages scanned, and the resulting digests can be decoded by recipients in ~20ms. Our schemes can thus practically attain the strongest form of receiver privacy for current applications such as privacy-preserving cryptocurrencies.
2017
EUROCRYPT
2017
JOFC
2017
JOFC
2015
EUROCRYPT
2015
CHES
2014
CRYPTO
2014
CRYPTO
2014
CHES
2013
CRYPTO
2012
EUROCRYPT
2010
JOFC
2010
EUROCRYPT
2005
CHES
2005
TCC
2003
ASIACRYPT
2003
CHES
2003
CRYPTO
2002
ASIACRYPT

Program Committees

Crypto 2019
Crypto 2017
Crypto 2012
Crypto 2009
Eurocrypt 2007