Key generation, device keys, session setup, and the guarantees end-to-end encryption actually provides, explained without hand-waving.
No. Instagram stopped supporting end-to-end encrypted DMs on 8 May 2026, so Meta can read every Instagram direct message again. What the opt-in feature was, why Meta says it pulled it, what happened to old encrypted chats, and where Messenger and WhatsApp stand now.
RCS is end-to-end encrypted only in some chats. Google Messages encrypts chats between its users with the Signal Protocol, and since May 2026 iPhone (iOS 26.5) to Google Messages chats are encrypted in beta under the GSMA's MLS-based standard when both carriers support it. Samsung Messages, business messages and SMS fallback are not.
Since March 2026 every Discord voice and video call, in DMs, group DMs, voice channels and Go Live, is end-to-end encrypted by default with the DAVE protocol, built on MLS. Stage channels are excluded. Text messages, DMs and attachments are not end-to-end encrypted, and Discord says it has no current plans to change that.
Standard Zoom meetings use AES-256-GCM, but Zoom's servers hold the meeting key, so they are not end-to-end encrypted. Zoom's opt-in end-to-end encryption, post-quantum since May 2024, works only in the Zoom apps and Zoom Rooms and turns off cloud recording, transcription and AI features. Team Chat is not end-to-end encrypted by default, and Zoom Phone only for upgraded 1:1 calls.
Slack EKM, Microsoft Purview Customer Key and Zoom Customer Managed Key put the master key in your own key vault, but the vendor still decrypts your content to run the service. Google Workspace client-side encryption and Microsoft Double Key Encryption keep the vendor out, but not your organization. Who holds the keys, where content is decrypted, what revoking does, and which to choose for your threat model.
Zoho Cliq encrypts data in transit and at rest with keys Zoho controls, so it is not end-to-end encrypted. Arattai end-to-end encrypts direct chats since November 2025, group chats since September 2026, and all calls, using the Signal protocol. Meetings, channels, Pocket and unencrypted backups are the gaps.
TreeKEM is the ratchet tree inside MLS. Members are leaves, parent nodes hold HPKE key pairs, and one UpdatePath replaces every key from a member's leaf to the root with about log2(n) ciphertexts. Here is how it works, with RFC 9420 section numbers, where the log(n) bound breaks, and what it does not do.
Google Meet meetings are encrypted in transit and at rest, not end-to-end. Legacy calls are end-to-end encrypted, personal Meet calls can be, and Workspace meetings need client-side encryption on Enterprise Plus or Education plans. Google Voice is not end-to-end encrypted.
Kyber-1024 makes every prekey bundle about ten times larger. Sizes worked out from the spec and libsignal, one-time vs last-resort keys, atomic claim-and-delete, replenishment, what the server must check, and measured PostgreSQL storage per device, using Lupyd's Firefly code as the worked example.
When two members of an MLS group commit at the same epoch, only one can win. A walk through the real code in Lupyd's open-source server and client: how the server picks the winner, what the losing client does, how Postgres backs it up, and the failure case we have not closed yet.
In October 2026 a researcher found that eight eMudhra intermediate CA keys were integers below 256. One was the number 4. Browsers blocked them within hours and distrusted a root. What went wrong, who was exposed, and what it does and does not mean for Indian digital signature certificates.
Google Chat encrypts messages in transit and at rest, but it is not end-to-end encrypted. Google holds the keys, meaning Google and Workspace admins can access content. Here is what firms need to know about compliance, risks, and safer alternatives.
Viral posts say WhatsApp just told a court it will leave India rather than break encryption. That hearing was in April 2024. The real 2026 story is different: a username standoff with MeitY, a SIM-binding deadline, pressure on safe harbour, and a traceability case that hasn't been decided.
Teams chats, channels, files and group calls are not end-to-end encrypted. Only one-to-one calls (if enabled) and Teams Premium meetings can be, and never chat. What Teams encrypts, how to turn E2EE on, and what it disables.
Slack is encrypted in transit and at rest, but it is not end-to-end encrypted on any plan, and Enterprise Key Management doesn't change that. What that means for DMs, exports, integrations and your team.
Signal, WhatsApp, iMessage, Element and Lupyd encrypt chats and groups end to end by default. Slack, Teams, Google Chat, Discord text and Instagram DMs do not. A table of 14 apps covering chats, groups and calls, checked October 2026.
Push notifications are where many encrypted apps leak message previews to Google. Here's how Lupyd sends a content-free FCM wake-up push, then fetches and decrypts messages on the phone, with real Kotlin and Rust code.
If the server can't read your messages, it can't search them. Here's how Lupyd searches end-to-end encrypted chats entirely on your device with SQLite FTS5 and Rust, with real code and honest tradeoffs.
Is Telegram really end-to-end encrypted? Learn how Telegram Cloud Chats and Secret Chats differ, why group chats lack E2EE, and how Lupyd ensures zero-knowledge privacy.
A friendly, plain-language guide to how digital keys work, how messages stay private, and why secret keys must stay on your phone or laptop.
Meet Noon: honest workplace surveys and public feedback forms where mathematical proofs make it impossible to trace who submitted what.