In an interview with the “world”, the mathematician Jean-Paul Delahaye comments on the recent technical advances carried by Ethereum, competitor of Bitcoin, which could reverse the hierarchy of cryptocurrencies.
Interview by
Jean-Paul Delahaye is professor emeritus at the University of Lille, specialist in theoretical computer science and the complexity of algorithms. He has just written beyond Bitcoin. In the world of blockchain and cryptocurrencies (Dunod, 270 pages, 19.90 euros), an educational book, but also engaged, on the strengths and weaknesses of cryptocurrencies, as well as on their future.
Why is a mathematician as you are interested in cryptocurrencies?
In 2008, Satoshi Nakamoto, which is still unknown who hides behind this name, proposed a protocol, Bitcoin, which creates an independent currency of any central authority, whose operation is based on collective control, all being Robust and safe. The key idea is that of the blockchain, a kind of account book recording transactions without the possibility of erasing pages, which is shared throughout the network. It is a great invention. Before him, others had tried to develop electronic currencies, but without success. What is new and revolutionary is the development of a protocol which assembles already known functions, but in an unexpected way, and which no one had imagined.
This protocol also benefited from several advances to launch in 2009. Encryption, essential to operation, was quite mature, as shown by the success of banking transactions on the Internet. Likewise, peer -to -peer or distributed networks worked for several years without problem. Finally, as the system is based on sharing a large file of around 500 GB, computers had to have enough memory and calculation capacity.
However, you plan to fail Bitcoin, whom you describe as “diplodocus”, “minitel of cryptocurrencies”, to “put away in a museum of computer science”. Why?
The main problem of the protocol lies in the way in which the validators of the new transaction pages to record in the blockchain are designated. With Bitcoin, the selected validator is the one who wins an equivalent calculation competition to offer a sort of grid of sudoku validates more and more, or release a six -dice six dice … In practice, the calculation is linked to a cryptographic problem hard. The consequence is that there is a competition, increasingly hard and more and more expensive in energy. Initially, the energy expenditure was low, then it increased tenfold every year to represent, depending on the estimates, the equivalent of the annual consumption of Switzerland or Sweden, of the order of 100 terawattheures! However, it is an unnecessary expenditure, because we can do without this type of method. This is why I am talking about bug, error for Bitcoin, which could have been better designed from the start.
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