Where not to learn about blockchain

I have been looking at writing a short introduction to blockchain (for managers and investors) and in looking at what other people have done, I have come across some really inadequate examples. Even Wikipedia (in English) does not clearly distinguish between the blockchain and applications such as cryptocurrencies. I have also looked at the Afrikaans and Dutch entries in Wikipedia but I think the German one says it best, in the first sentence.
"Unter einer Blockchain (auch Block Chain, englisch für Blockkette) wird eine Datenbank verstanden, deren Integrität (Sicherung gegen nachträgliche Manipulation) durch Speicherung des Hashwertes des vorangehenden Datensatzes im jeweils nachfolgenden gesichert ist."
This is simple and accurate! The two items below are, in my view, examples of unnecessarily confusing attempts to explain.

What is Blockchain – Explained in simple English https://mybroadband.co.za/news/internet/200218-what-is-blockchain-explained-in-simple-english.html

Chain introductory video – https://chain.com


Electronic Soleau envelope sees the light

For about 100 years now, the French Patent & Trademark Office (INPI) has been offering the Soleau envelope service that allows one to deposit two copies of a document with the Office, individually sealed in envelopes that are stamped and perforated by INPI. One envelope is then returned to the deponent. The Office keeps their copy for five years, during which the deponent can request its return by mail and the idea of course is that this can prove the age of a document because the two envelopes can be opened, for example, in a court. Deposition itself confirms no rights, however. It simply provides a cheap way to prove authorship or prior art etc. and the current price of the service, for up to seven A4 pages, is €15.

There is now an electronic version for which INPI provides an electronic fingerprint (hash) and stores the original file (in the owner's account). This is better described at the French-language link below. Casual inspection did not reveal a public proof checking facility, something that is in fact provided by the company MaPreuve, for example. MaPreuve requires a Java application, which none of the browsers on this computer wanted to load, but this would be a really useful service. Storing the original document electronically, in my view, detracts from the value of the INPI service and I would have been happier if they had just stored the electronic fingerprint.

Set up of electronic Soleau Envelope – https://www.ipside.com/content/set-electronic-soleau-envelope
e-Soleau – https://www.inpi.fr/fr/services-et-prestations/e-soleau
MaPreuve Proof verification service – https://www.mapreuve.com/en/verifier-une-preuve.php


OCRed Kindle edition of Pinball Games

I just finished reading (on the beach) Pinball Games by George Eber, a book recommended (I think) by a year-end edition of Forbes magazine, dealing with the War and subsequent Russian occupation of Hungary. It was very informative and although it covers a sombre period, very amusing and sweet in places. Nevertheless, there were some very problems with the edition.

  1. Obvious OCR errors like "carne" instead of "came". This is not really acceptable in an e-book edition selling for more than $10 (US).
  2. Inconsistent and incorrect use of Hungarian diacritical signs with some place names having all, some only some and some none ("Mosonmagyarovar") of the correct accents. It is possible that this was the case in the printed edition as well.
  3. Inconsistent use of translations, especially of place and personal names and honorifics (sometimes "néni" without explanation and sometimes "aunt" and so on) which were probably inconsistent in the original manuscript and should have been fixed by the original editor.
The book was actually rather moving and one has to admire the fortitude of the author and other characters. It was also a beautiful insight into the lives of the bourgeoisie of pre-War Budapest and contained many interesting vignettes of economic life during the difficult years. Nevertheless, I think that the traditional publishing industry needs to produce a much higher-quality product if it wants to distinguish itself from new media but perhaps they have already given up...


TV licence system collapses on "Black Friday"

On the highly artificial (recently introduced) shopping event known as "Black Friday", the otherwise not very reliable SABC reports that "the TV Licence validation server was overwhelmed by the abnormal increase in validation requests from retailers due to the Black Friday deals which resulted in the server timing out between 07:00 and 10:30". Of course, there were no reports of point-of-sales systems or mobile networks going down... I will try to explain here why this breakdown was complete unnecessary.

Retailers have to see an SA ID document (or, sometimes, photocopy or photo of one) and verify that the person to whom the ID number belongs has a valid television licence. Now, this information is not updated frequently since a licence is valid for one year and, frankly, I don't think many new licences are being issued. It would therefore be sufficient to publish (and distribute) a list of ID numbers for which a valid licence exists but this presents two problems.

  1. It might be a bit too easy for someone buying a television set to just pick a number from the list and use it (in cooperation, probably, with retail staff).
  2. There might be (mild) privacy concerns.

Both issues would be addressed by publishing a list of hashed ID numbers and allowing retailers to store a local copy. A hash function is a one-way function f that would work as follows. First, the SABC publishes a list of all f(x) where x runs over the ID numbers of persons with a valid licence. For technical reasons, we might prepend the digit 1 to the ID number. The essence of the one-way function is that if you are given f(x) (the hashed value), it is in practice impossible to compute x from it although the forward calculation is quite easy.

The list of hashed ID numbers cannot be used therefore to extract any specific ID number but the holder of a valid licence could present their ID number x to the retailer who would quickly compute f(x) and compare f(x) to the published list, a copy of which the reailer will have. If this f(x) is on the list then there is a valid television licence and the retailer can go ahead to make the sale without consulting the SABC server.

It would be necessary to update the list with some (not very specific) frequency but this could be done at any time and will not disrupt sales to customers. In a follow-up post, I shall describe an example of such a one-way function. The image of the sometimes SABC CEO and high-school dropout above is used without permission but under the assumption that it constitutes fair use under SA copyright law. In fairness, I should say that I once had good service from the SABC when I needed to cancel a licence but my friends regard this as unusual and strange.