REZEIVER - Realistic time-based encryption
Motivation
The amount of digital data grows steadily through applications like Cloud Computing, Big Data and the Internet of Things. Encryption allows for effective protection of these data from unauthorized access. Once encrypted, a message requires the right key and appropriate computational power to be read.
So far, enabling decryption only after a certain period of time can only be implemented relying on a third party or demanding large computational resources. Adding an expiration date to the encryption of a document can be used to "send a secret into the future". As in a postal voting, votes will only be published at a specific date.
A concept implementing time-based encryption without the drawbacks of conventional approaches has first been published in 2015. It uses the results of an unrelated public computation but unfortunately is not efficient enough yet, to be used in practice.
Approach
In the research project REZEIVER practical techniques and algorithms for time-based encryption are developed using blockchain technology. Blockchains are steadily growing datasets that are stored in a multitude of distributed databases in order to be protected against manipulation. Cryptocurrencies like Bitcoin implement this concept. REZEIVER aims at encrypting a message such that a blockchain of a certain length serves as a key for for decryption. Thus, the decryption key is unknown at the time of encryption. Efficient encryption is investigated as well as alternative computational problems that can implement the new concept in practice.
Innovation and Perspectives
Applications of efficient, time-based encryption can be found in various fields. Time-based publication of announcements and fair lotteries, in which the opening of tickets is public, are only two examples. Privacy applications, in which data is kept secret for a period of time before revelation are particularly interesting for society (i.e. census data). The confidentiality of future transactions in finance and the provisioning of digital exams in e-learning are further examples.
Funding
The project REZEIVER is part of the innovation funding IKT2020 of the Federal Ministry of Education and Research "Disruptive Innovationen für Kommunikationssysteme und IT-Sicherheit". It comprises a PhD position (4 man-years) and a postdoctoral position (2 man-years). The project runs from January 1st, 2017 to December 31st, 2020.
