Encryption and key custody

Encryption, explained plainly

Synapse Chat encrypts your data in two places:

• In transit: between your device and our servers.
• At rest: while it is stored on our infrastructure.

This protects your communication from being intercepted in flight or read directly from storage.

Why Synapse is not end-to-end encrypted

In a fully end-to-end encrypted system, only the sender and recipient hold the keys, and the service provider can never access message content. Synapse Chat is deliberately not built this way.

Instead, Synapse holds the encryption keys. We made this choice so the service can meet legal and compliance obligations. The most important of these is legal hold, where there is a lawful requirement to preserve and, if compelled, produce records.

Because Synapse holds the keys, Synapse Chat cannot be described as end-to-end encrypted, and we never describe it that way.

What key custody does and does not mean

It does mean:

• Synapse is technically capable of accessing stored content where lawfully required.
• The service can support legal-hold and compliance obligations.

It does not mean:

• That we routinely read your messages. We do not routinely scan message content.
• That access is casual or unmonitored. Access is governed by strict internal controls, limited to specific circumstances, and audited.

Why this matters for you

Key custody is a trade-off made for a regulated environment. It is also why the single most effective privacy control is in your hands: keep communication de-identified. If identifiable patient information is never entered, it can never be exposed. See De-identified by default and How Synapse protects your data.