Publications by Gwangbae Choi | EPFL Graph Search

Towards Witness Encryption Without Multilinear Maps

Current proposals of extractable witness encryption are based on multilinear maps. In this paper, we propose a new construction without. We propose the notion of hidden group with hashing and make an extractable witness encryption from it. We show that the ...

2021

Post-Compromise Security in Self-Encryption

Serge Vaudenay, Gwangbae Choi, Fatma Betül Durak

In self-encryption, a device encrypts some piece of information for itself to decrypt in the future. We are interested in security of self-encryption when the state occasionally leaks. Applications that use self-encryption include cloud storage, when a cli ...

2021

Time in cryptography

Gwangbae Choi

Time travel has always been a fascinating topic in literature and physics. In cryptography, one may wonder how to keep data confidential for some time. In this dissertation, we will study how to make private information travel to the future. This dissertat ...

EPFL2020

Timed-Release Encryption With Master Time Bound Key

Serge Vaudenay, Gwangbae Choi

Timed-release encryption allows senders to send a message to a receiver which cannot decrypt until a server releases a time bound key at the release time. The release time usually supposed to be known to the receiver, the ciphertext therefore cannot be dec ...

2019

Protecting Privacy and Security of Genomic Data in i2b2 with Homomorphic Encryption and Differential Privacy

Jean-Pierre Hubaux, Gwangbae Choi, Nathalie Jacquemont, Jean Louis Raisaro, Nicolas Rosat

Re-use of patients’ health records can provide tremendous benefits for clinical research. Yet, when researchers need to access sensitive/identifying data, such as genomic data, in order to compile cohorts of well-characterized patients for specific studies ...

IEEE2018

Privacy-Preserving Exploration of Genetic Cohorts with i2b2 At Lausanne University Hospital

Jean-Pierre Hubaux, Gwangbae Choi, Nathalie Jacquemont, Jean Louis Raisaro, Nicolas Rosat

Re-use of patients’ health records can provide tremendous benefits for clinical research. One of the first essential steps for many research studies, such as clinical trials or population health studies, is to effectively identify, from electronic health r ...

2016