Donating 256 ETH, Vitalik Bets on Privacy Messaging: Why Session and Simplex?

Original Title: "What is Vitalik's Donation Recipient, Privacy Messaging App Session, and SimpleX?"

Original Author: ChandlerZ, Foresight News

Ethereum co-founder Vitalik Buterin recently turned his attention to a relatively niche track: privacy-focused instant messaging. In a Tweet, he expressed that end-to-end encrypted communication is crucial for privacy protection, with the next key steps being "permissionless account creation" and "stronger metadata privacy protection," and he openly endorsed two apps moving in this direction – Session and SimpleX. To support this, he donated 128 ETH to each of these two apps.

This raises a specific question: in a landscape where WeChat, Telegram, and WhatsApp already dominate user mindshare, what differentiation are these privacy-centric chat tools bringing? What technological path is Vitalik betting on?

Why Vitalik Stepped In: From Content Encryption to Metadata Privacy

Compared to "how much money he donated," the issue emphasized by Vitalik this time is more worthy of attention.

In his explanation, he pointed out that existing end-to-end encryption only solves the confidentiality of "message content," but there are still two clear shortcomings:

Account creation relies on phone number/email and cannot achieve true "permissionless" status

· Mainstream IM apps (including many encrypted chat tools) require phone number registration.

· This means that telecommunications providers, email service providers, and even various national regulatory agencies could all become a "single point of failure" for your digital identity.

Metadata remains highly exposed

· Who is chatting with whom, when they are chatting, for how long, what devices are being used, which network is being used – all of these fall under metadata.

· Even if message content is encrypted, a finely detailed social graph can still outline a person's life trajectory and relationship network.

In a tweet, Vitalik explicitly pointed out that making breakthroughs in these two aspects almost certainly means moving towards a higher degree of decentralization. "Metadata privacy protection requires decentralization, which is difficult to achieve in itself; and the expected multi-device support from users is even more challenging. Furthermore, increasing the difficulty in resisting sybil attacks / denial of service attacks in the message routing network and user end (without mandatory reliance on phone numbers) adds to the complexity. These issues need more attention."

Session and SimpleX have become the two projects he mentioned and donated to. However, he also pointed out that these two pieces of software are not flawless and there is still a long way to go to truly achieve the best user experience and security.

What is Session?

If summarizing Session in one sentence, it is more like an encrypted messaging tool that tries to take Signal half a step forward: while maintaining end-to-end encryption, it attempts to minimize the presence of phone numbers, centralized servers, and observable metadata in the system. At first glance, the use of Session is not much different from regular IM—install the app, create an account, add contacts, create groups, send text and files; these paths are all familiar. But underneath, it has made several key changes to the "account" and "message network."

First is the account system. Session does not require users to provide a phone number or email. When entering the application for the first time, the system will generate a random Session ID for you, which is your unique identifier. The platform neither knows your real contact information nor needs to rely on telecom operators or email service providers to vouch for you. This directly bypasses the real-name or semi-real-name registration system widely relied upon by mainstream IM platforms, making the account creation process more in line with Vitalik's concept of permissionlessness.

Second is the message transmission path. Session does not throw all data to a centralized backend for forwarding and storage; instead, it is built on the Oxen blockchain and its Service Node network.

In simple terms, these Service Nodes participate in block validation and also play a role in message relay and storage in the network, forming a decentralized communication network. When messages are passed between nodes, they go through an onion routing mechanism similar to Tor, where each hop node only knows the previous and next hops, unable to see the complete path, thereby design-wise minimizing the possibility of a single entity knowing your communication graph.

Of course, this architecture also brings practical trade-offs. Onion routing and decentralized storage naturally make latency and stability inferior to a direct connection to a central server. Regarding multi-device usage and message synchronization, Session currently cannot achieve the smooth experience of seamlessly logging into a new device and automatically pulling the entire message history like Telegram or WhatsApp.

In May of this year, Session announced the official launch of its native token, SESH, and the migration to Arbitrum. This token will be used to incentivize the DePIN network, consisting of over 2000 nodes. In terms of tokenomics, the maximum token supply of SESH is 240 million, with 80 million unlocked at the initial issuance. Node operators are required to stake 25,000 SESH tokens to participate in network maintenance.

What is SimpleX?

Compared to Session, SimpleX has a more aggressive goal: it does not enhance privacy within an existing instant messaging framework but rather almost entirely redesigns a set of communication methods at the protocol layer to minimize the generation of aggregatable metadata.

In SimpleX, communication partners do not send messages to each other through two accounts but rather transmit and receive messages through a series of pre-established unidirectional message queues. You can think of it as: each relationship corresponds to a set of channels dedicated to that relationship alone. Messages are relayed along these channels by intermediary servers, but the servers only see data flowing from one queue to another. It is difficult for them to piece together a complete social graph from the protocol layer.

Due to the absence of a traditional global user ID in the system, external observers cannot, as in many centralized IM platforms, reconstruct a person's recent chat partners, intersections, or community structure through server-side metadata analysis to create a social relationship map.

This design also significantly impacts user experience. In contrast to Session, SimpleX is less likely to provide an immediate sense of familiarity as a regular messaging app. You cannot search for a username to add a friend as in Telegram; instead, you rely more on one-time invite links, QR codes, or other out-of-band channels to establish contact. The paradigms of multi-device use, data backup, and migration are no longer automatic syncs by entering a phone number or password; users must understand and cooperate with this privacy-centric workflow.

From a perspective that pursues ultimate privacy, these additional steps are necessary sacrifices. However, from the viewpoint of the general user, they directly translate into higher onboarding hurdles and cognitive burdens.

Therefore, SimpleX is more like a niche tool for users who are extremely concerned about metadata exposure and are willing to bear the experience cost. It may find it challenging to attract a large-scale mainstream user base in a short time, but on the technological path, it provides a very clear reference sample. If we truly prioritize reducing observable metadata as the highest priority, rather than features, convenience, or user scale, what could an instant messaging protocol be transformed into?

Vitalik's decision to donate funds to it is largely a commitment to picking up the tab for this experiment that aims to erase user IDs and social graphs at the protocol layer, allowing this relatively idealistic path to have more time to refine and iterate.

Returning to that simple question, are these tools worth the average user's attention?

When discussing Session and SimpleX, it's hard to ignore Signal, which has been the industry benchmark for "privacy chat" over the past few years. Today, many encryption communication protocols on the market actually adopt or draw inspiration from the Signal Protocol to varying degrees. This protocol uses mechanisms like Double Ratchet and forward secrecy to establish a relatively mature engineering standard for end-to-end encryption.

For most users, as long as the chat partner is willing to migrate platforms, Signal has already provided a balanced choice between security, usability, and cross-platform support. Its open-source implementation, end-to-end encryption of content, interface close to mainstream IM, and multi-platform support make it one of the preferred tools for journalists, activists, developers, and privacy enthusiasts.

Vitalik Buterin stated in his speech at the 2025 Shanghai Blockchain International Week that with the development of ZK technology and cryptography, "Not your key, not your coin" will evolve into "Not your silicon, not your key," where hardware trustworthiness will become a focal point of cryptographic and security developments. Currently, the marginal cost of the cryptographic techniques used by encryption communication applications, including Signal, is so low that users are unaware of it.

He believes that as the cost of encryption further decreases, more and more applications in the future will be able to leverage low-cost encryption technology, shifting from "why use ZK" to "why not use ZK." He also looks forward to exploring new use cases with developers worldwide.

However, for industry practitioners and privacy-conscious users, the more immediate issue is likely not which tool will become the next WeChat, but rather a more specific choice between two options.

Are you willing to pay a little usability cost for privacy? Are you willing to accept having one or two more chat entry points reserved only for specific relationships or scenarios besides WeChat/Telegram being the default world? In other words, what we care about is not whether to completely replace the mainstream IM, but whether we can carve out an additional secure room for those truly sensitive conversations.

If your answer is yes, then these few names probably don't need to wait to become popular before they are worth paying attention to. Even if they may have a hard time becoming the average user's main chat tool in the short term, Session and SimpleX, as mentioned by Vitalik, have at least provided two clear paths: one is to minimize metadata and account dependencies in a familiar IM form, and the other is to cut into user IDs at the protocol layer, trying to prevent the social graph from forming in the system.

When it comes to whether the average person should care about this issue, these apps may not need to be front and center on your phone just yet. However, they are certainly worthy of a dedicated spot on your desktop, reserved for those conversations you prefer not to entrust to the major platforms.