How xx messenger is Future-Proofing Private Communication

By Decrypt Staff

Encryption lies at the heart of modern-day communications; it prevents potential snoopers like hackers, private companies or even governments from decoding messages, guaranteeing your online privacy.

But the current generation of popular encrypted messaging apps like WhatsApp and Signal have two glaring vulnerabilities. First, they're built atop centralized servers, which represent single points of failure and leak metadata about who you're talking to and when. And second, encryption itself faces a major threat in the near future—quantum computing.

At the 2020 World Economic Forum in Davos, Sundar Pichai, CEO of Google’s parent company, Alphabet, made a stark prediction: "In a five-to-10-year time frame, quantum computing will break encryption as we know it today." Current-generation apps, and even blockchains, aren’t designed by default to stay resilient in such cases. That poses a problem.

In order to protect users' privacy—and in more severe cases, their physical safety—a new generation of decentralized, quantum-resistant messaging apps is emerging, led by xx messenger.

The brainchild of cryptographer David Chaum, xx messenger aims to address both today's privacy concerns and potential future vulnerabilities through a combination of innovative technologies. Chaum's pedigree is well-established; widely known as “the father of online anonymity,” he's also the inventor of the first digital currency, DigiCash—considered one of the key inspirations for Satoshi Nakamoto's Bitcoin whitepaper.

On the surface, the xx messenger app should feel familiar to anyone who has been using a messaging app, with features including group chats, photo and audio sharing. And xx messenger also makes it much easier to sign up and use without linking the account to a phone number or an email—pseudonyms alone suffice. That alone makes for a subtle, but at the same time fundamental shift from the messaging app status quo.

Where xx messenger significantly differs from other messaging services, though, is the privacy-preserving technology underpinning the platform.

The quantum challenge

To appreciate the challenges xx messenger seeks to tackle, it's helpful to put a few things into context. 

Modern computers operate in terms of binary digits—1s and 0s. If something is “true” in computer terms, then the transistor will code a 1. If false, it will read 0. But due to a phenomenon called “quantum superposition,” the transistors in quantum computers can read both 1 and 0 at the same time, a capability that currently doesn’t exist and would help crack encryption in many cases—even Bitcoin, according to some experts. 

Acknowledging the impending risks, Chaum and his team have developed a quantum-secure consensus algorithm, xxBFT—or xx consensus, as it’s commonly called—and combined it with a message mixing protocol called xx cMix to underpin all of its projects.

The novel consensus model ensures the network infrastructure itself can’t be taken down by quantum computers, while cMix ensures end-to-end encryption can’t be broken—and provides xx messenger's unique privacy-preserving feature, metadata shredding. Using cMix, metadata shredding prevents messages from being linked or decrypted, while obfuscating information about senders, receivers, and messaging dates. Where previous generations of messenger apps kept the content of your messages private, xx messenger goes a step further, breaking the link between you and who you’re talking to—information that could be used to build up a profile of you.

Decentralized solutions

xx messenger further secures its technological infrastructure by building on the decentralized xx network. Running on a decentralized blockchain rather than centrally-controlled private servers eliminates single points of failure and removes incentives to monetize data (which exposes users to data privacy risks). The benefits of decentralization are compounded when Chaum’s quantum-resistant cryptogtaphy is added to the mix.

While relying on quantum-resistant cryptography, xx network, on which xx messenger is built, works similarly to other decentralized blockchains. Randomly assigned pools of xx nodes on the network help encrypt anonymity sets of 1,000 messages sent through xx messenger. Nodes continuously shuffle these messages and help encrypt them in line with the deployed technology stack. This is the process that also eliminates any information that can link senders and receivers.

The app runs on a decentralized network of 360 nodes, at time of publication, but xx messenger says the goal is to increase that number to 500.

As with other blockchains, xx network is secured by economic incentives; in exchange for their services to secure the network, node operators earn xx network’s native cryptocurrency, xx coin. While blockchain networks like Ethereum have an “upgrade path” to prepare for a quantum future, xx coin is currently the only cryptocurrency protected from quantum computing attacks. 

xx messenger’s technical development benefits from open-source cryptography development, welcoming developers to contribute both to ongoing projects and build new apps on the network. The source code, written mostly in Golang, is available on GitLab with code discussions taking place on MainNet Forum and Discord.

The xx messenger app is currently available for download on the Android and Apple app stores. If you'd like to get involved with xx messenger’s privacy-conscious community, check out the project's YouTube, Twitter, Telegram, and Discord.

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