by Bozho | Jul 29, 2018 | Aggregated, blockchain, digital signatures, Opinions, security
Recently technical and non-technical people alike started to believe that the best (and only) way to prove that something has happened in an information system is to use a blockchain. But there are other ways to achieve that that are arguably better and cheaper. Of course, blockchain can be used to do that, and it will do it well, but it is far from the only solution to this problem. The way blockchain proves that some event has occurred by putting it into a tamper-evident data structure (a hash chain of the roots of merkle trees of transactions) and distributing that data structure across multiple independent actors so that “tamper-evident” becomes “tamper-proof” (sort-of). So if an event is stored on a blockchain, and the chain is intact (and others have confirmed it’s intact), this is a technical guarantee that it had indeed happened and was neither back-dated, nor modified. An important note here – I’m stressing on “digital” events, because no physical event can be truly guaranteed electronically. The fact that someone has to enter the physical event into a digital system makes this process error-prone and the question becomes “was the event correctly recorded” rather than “was it modified once it was recorded”. And yes, you can have “certified” / “approved” recording devices that automate transferring physical events to the digital realm, e.g. certified speed cameras, but the certification process is a separate topic. So we’ll stay purely in the digital realm (and ignore all provenance use cases). There are two aspects to proving digital events – technical and legal. Once you get in court, it’s unlikely to...
by Bozho | Feb 22, 2017 | Aggregated, digital signatures, eletronic identification, Opinions, smart cards
A smart card is a device that holds a private key securely without letting it out of its storage. The chip on your credit card is a “smart card” (yup, terminology is ambiguous – the card and the chip are interchangeably called “smart card”). There are smaller USB-pluggable hardware readers that only hold the chip (without an actual card – e.g. this one). But what’s the use? This w3c workshop from several years ago outlines some of them: multi-factor authentication, state-accepted electronic identification, digital signatures. All these are part of a bigger picture – that using the internet is now the main means of communication. We are moving most of our real-world activities online, so having a way to identify who we are online (e.g. to a government, to a bank), or being able to sign documents online (with legal value) is crucial. That’s why the EU introduced the eIDAS regulation which defines (among other things) electronic identification and digital signatures. The framework laid there is aimed at having legally binding electronic communication, which is important in so many cases. Have you ever done the print-sign-scan exercise? Has your e-banking been accessed by an unauthorized person? Well, the regulation is supposed to fix these and more more issues. Two factor authentication is another more broad concept, which has a tons of sub-optimal solutions. OTP tokens, google authenticator, sms code confirmation. All these have issues (e.g. clock syncing, sms interception, cost). There are hardware tokens like YubiKey, but they offer only a subset of the features a smart card does. But it’s not just about legally-recognized actions online and two-factor...
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