A few weeks ago, I received a book with the collected writings of Georg Cantor, edited by Ernst Zermelo and entitled “Georg Cantor: Gesammelte Abhandlungen: Mathematischen und Philosophischen Inhalts.” It is a reprint of the original from 1932. I had read some Cantor before, but having all of his writing in one handy tome, with some comments by Zermelo, was really inspiring. Hence this article.

Warning: some knowledge of the German language will be useful, also I have not used mathematical formulas because of Medium’s limitations.

A first encounter with accumulation points (1870)

Shortly after obtaining his doctorate, the young mathematician Georg Cantor was asked by his…


TLDNR — Reintroducing the use of peer-to-peer credit on a large scale, with governments partially guaranteeing the IOUs being issued, could help mitigate the cash crisis many companies face because of COVID-19.

In a short LinkedIn article, entitled IOUs as tools of economic autonomy, I recently noted that direct credit operations between businesses, for example via bills of exchange, have mostly disappeared in the Western world. The last country where this was done on a large scale was Germany: as late as 1986, the rediscounting of corporate bills of exchange (“Wechsel”) still represented 60% of central bank liquidity for German…


I have been involved in blockchain for close to five years now, and was a co-organizer of what was probably the first “serious” blockchain conference in Luxembourg in the summer of 2015, focusing mostly on researchers and academics rather than evangelists. I saw the potential of this technology, but was always extremely puzzled by the “bitcoin is the future of money” crowd. In fact, one of my reasons for getting rather deeply involved in blockchain is to show that while crypto is not money, blockchain can be the technology from which a real revolution of our monetary systems might emerge…


Isekai (https://github.com/sikoba/isekai) is a verifiable computation framework that will allow to work with several programming languages and verifiable computation systems while using a single code-to-circuit module. This article provides a quick and basic intro to installing isekai on Windows.

Install Ubuntu on Windows

isekai is written in Crystal, which has not yet been ported to Windows. Therefore, the first step is to install a Linux subsystem.

To enable the “Windows Subsystem for Linux” feature (as described here), open Windows PowerShell as Administrator and run:

PS C:\>Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux

You will be asked to restart Windows.

Next, install “Ubuntu 18.04 LTS” which can be…


This month, we held an isekai workshop and our new CTO Guillaume Drevon has started integration testing of isekai. Development of the Sikoba mobile app is proceeding as planned, with a first “internal” release due in the second half of March.

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A sneak peek at the curve used in the isekai logo

Sikoba Research

At the beginning of February, our new CTO Guillaume Drevon joined Sikoba Research and is now leading the development of the isekai verifiable computation project. Guillaume is an experienced software engineering manager, having led development teams in a wide range of technologies, from windows…


Zero-knowledge rendering of “Isekai” © Klaudia Kampa

Isekai is a verifiable computation framework that will work with several programming languages and verifiable computation systems while using a single code-to-circuit module. Isekai is being developed by Sikoba Research using Crystal, with the support of Fantom Foundation. We seek to cooperate with researchers and developers who work on verifiable computation projects, as well as with blockchain projects that want to offer verifiable computation.

If you are interested to cooperate with us, or to find out more, please contact our CTO, Guillaume Drevon — gd at sikoba dot com.

What is verifiable computation?

Verifiable computation allows one to outsource the processing of some function…


TL;DR — in the context of a state machine replication system, so-called “smart contracts” are user-defined components of the transition function. The idea that they must be immutable does not make much sense.

State machines

The essential part of a state machine replication system is the replication mechanism, also called the consensus protocol. The consensus protocol ensures that all honest nodes in the network (eventually) agree on their state, even in the presence of computer failures, network delays and possibly malicious or byzantine behaviour by some nodes.

State history

In some systems, consensus on the current state is all that is needed. On an…


In casual use, the word “money” carries a very wide range of meanings. Let’s introduce a simple vocabulary to help clarify the meanings of this word.

Private property, jewellery and the need of keeping track

For over a million years, and until about 10,000 years ago, our ancestors lived as hunter-gatherers in small bands of a few dozen people. Their survival depended on sharing what little they had. Among items that were not subject to communal sharing were body adornments: amulets, talismans, lucky stones etc. These probably played a role in the gradual emergence of private property and of the…


With the rise of crypto-assets, more people are getting exposed to the concept of cryptographic accounts, “wallets”, public and private keys. Also, there are now numerous projects working on identity management and digital ID using cryptography and blockchain technology.

As a human being, you have very strong assurance that, as long as you are alive, your identity can be neither compromised nor lost. It is just about impossible to impersonate someone in front of people who know that person, and even identical twins have unique fingerprints and irises! …


So you want to get filthy rich? No problem pal, just send a dollar worth of bitcoins to my good friends at BitWise, they will take care of you. Make sure to quote my very special discount code SUCKERRR and they will even credit your bitcoin sending fees.

Too good to be true? Are you kidding me? These guys are posting their ads on one of the top crypto sites in the world, it’s called coinmarketcap.com. More legit than that, you die.

Alex Kampa

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