2016-11-28

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.

http://mybroadband.co.za/news/broadcasting/189340-black-friday-takes-down-tv-licence-system.html

2016-09-17

Hiperskakels en die saak Sanoma/Playboy teen GeenStijl

Die Europese Hof van Justisie het vroeër dié maand beslis dat die publiseer van skakels (dit wel sê, nie die inhoud self nie maar net 'n "link") na roofkopieë van foto's van 'n Playboy-model op die Nederlandse webwerf GeenStijl neerkom op inbraak op outeursreg deur GeenStijl. Die Hof het dus eintlik beslis dat die Internet-adresse van die foto's opsigself die eiendom van Sanoma, die uitgewers van Playboy, is. Die regter het bepaal dat "er sprake is van inbreuk, omdat GeenStijl als commerciële partij behoorde te onderzoeken of de foto's met toestemming online waren geplaatst". Dit is 'n problematiese besluit vir verskeie redes waarvan die meeste voor-die-hand-liggend is. Dit raak egter aan die basiese probleem van outeursreg vir digitaal verspreide media: elke gebruiker maak per definisie 'n perfekte (verder kopieerbare) afskrif van die materiaal. Slegs mense wat nie reeds bedruk is oor die agteruitgang van die Weste (en spelling) nie, word aanbeveel om GeenStijl te besoek.

'Uitspraak GeenStijl is een vervuiling van het auteursrechtelijke systeem'

2016-08-11

Enkripsie is net wiskunde, behalwe dalk in La France

Volgens Frankryk se minister van binnelandse sake, Bernard Cazeneuve, is enkripsie 'n „sentrale” probleem in die geveg teen terrorisme. Gewilde kletstoepassings soos Telegram wat privaatgesprekke moontlik maak, word oënskynlik deur terroriste gebruik (net soos treine, skoene en ander normale dienste en voorwerpe) en maak onderskepping deur die owerhede onmoontlik. Ongelukkig vir die heer Cazeneuve (hiernaas afgebeeld) is enkripsie niks anders as 'n wiskundige algoritme nie en enige twee partye kan in beginsel 'n geënkripteerde verbinding bewerkstellig, ook sonder 'n spesifieke tussenganger soos Telegram. Trouens, Telegram is niks anders nie as 'n algoritme wat op beide se toestelle (toevallig, selfone) loop en die Internet gebruik om data oor te dra. Hy kan dus (i) die Internet; (ii) rekenaarprogramme of (iii) die basiese universiteitsvlak-wiskunde verban. Dan sal daar ook sommer geen GMail of Internet-bankdiens (of moderne Frankryk) wees nie. Blykbaar gaan dit minstens 'n spitsberaad met sy Duitse ampsgenoot verg om dié les te leer...

Bron: Bernard Cazeneuve veut une action internationale contre le chiffrement http://www.macg.co/ailleurs/2016/08/bernard-cazeneuve-veut-une-action-internationale-contre-le-chiffrement-95199

2016-07-02

Financial services – a huge network effect?

According to Wikipedia, when "a network effect is present, the value of a product or service is dependent on the number of others using it". More precisely (for a positive effect): each new user increases, if only slightly, the value of the service for all existing users. Since I have been having a minor spot of trouble with a Bitcoin wallet provider, I have unfortunately realized that this network effects exists rather dramatically for financial services in the following obvious sense. If the remote and electronic financial service provider denies me access to my funds (which, admittedly, it does less frequently than my brick-and-mortar bank) then the immediate feeling is one of distinct discomfort that there will not be a substantial mob in my immediate vicinity to storm the (virtual) bank. Perhaps it matters little that the mob is distributed all over the planet but in this case one remains faced with the issue of (a) finding the other customers; and (b) finding something to storm.

2016-06-01

Microsoft Azure "Hotel California" newsletter

It has been days now and I remain unable to unsubscribe from the Microsoft Azure newsletter and basically their response is to tell me that I should reboot...