What is Signal and how it works

Signal is a messaging application which makes safety its core strength. He even recommends it Edward snowden, the former NSA analyst involved eight years ago in denouncing US espionage activities and for years taking refuge in Russia. From time to time, with updates to the conditions of use or some privacy issues related to the most used apps, Signal rightly returns to be talked about by recording a peak in downloads. In this case, the increase in recent days – in first place in the United States, second also in Italy – is linked on the one hand to new rules imposed by WhatsApp on all users, to be approved by February 8 (we talked about it here) and, on the other, toendorsement provided on Twitter by Elon Musk, patron of SpaceX and Tesla among other companies, to the chat used by a large number of users who care about the confidentiality of data and information.

Signal is available for Android, iOS e desktop for Windows, Mac and Linux distributions (but if your device does not have the Google store, as in the case of Huawei, it is sufficient download the APK kit from the official website). Just download it from the dedicated app stores, being careful that it is the original version, that is the private messenger developed by the non-profit software group Open Whisper Systems. On the other hand, even Signal itself is an open source platform – on GitHub you can find the source code – and no profit. You need to register with your own telephone number, enter the verification code (or wait for automatic verification on Android) e start using the chat. Signal increases every privacy system in favor of the user: does not store any messages or content on its servers, locations and profile pictures but only the time of account creation and last login.

In practical terms, the application does not seem very different from the many we are used to chat with: at the first access you can choose to import group conversations from another app. You can make phone calls, send messages and many types of content, share your GPS position, record and send voice messages and make group calls and video calls for up to five people. All this while guaranteeing maximum privacy using numerous encryption algorithms (Curve25519, AES-256 and HMAC-SHA256 among them) that protect all the contents that are exchanged, including videocalls. At the time of installation, and then periodically, all Signal users generate a number of cryptographic keys and register with a key distribution server. On the contrary, WhatsApp, even more from 8 February, will share the metadata of chats (certainly not the contents, protected and encrypted, but everything that revolves around them), with all the products of the group, effectively profiling the user on all platforms and allowing to be targeted by advertising between the various systems. Although, it is worth mentioning, the end-to-end encryption, which WhatsApp also offers, it is never 100% safe: the path of the contents is covered but if one of the two ends is compromised, the message can be stolen.

In any case, in addition to privacy in the latest wave of success for Signal, there are also political reasons, that is the opposition to the idea that Facebook can unilaterally change the conditions by actually sharing the databases of its services to the advantage of their business. On Signal, among other things, it is possible to set thetimed self-destruction of messages (5 seconds to a week after display), check the contact security code, comparing the cryptographic keys of his account with those on his device to make sure that there are no misalignments of the conversation, use a pin to unlock the app and set a series of other elements that, like those already seen, aim to strengthen to the maximum privacy. Signal has always rejected any accusations of having been violated – as happened for example at the beginning of the year by the Israeli protection company Cellbrite.