End-to-end encryption

How it works

TLS to a provider is not end to end if the provider decrypts and stores plaintext. End to end means the provider holds ciphertext and does not hold the key. Recovery and search usually disappear with that choice.

A whistleblower uploads through a client that encrypts first. The provider's logs show a blob size and a time, not the contents. A portal that previews the PDF on the server is not this design, whatever the badge says.

How it differs

End-to-end is the strict version of zero-knowledge claims. Transit encryption is the hop.

A key baked into the URL can land in a proxy log.

Keep keys out of query strings.

On the ticket

• The practical close is a log line: time, actor, byte count, result.
• Without that line the transfer is a story.
• With it, the next person can see whether this door did what the ticket claimed.
• If the path is shared, say so in the partner profile so a later change does not silently pick a different limit, key, or region.
• On a real ticket, write down the door, the byte count, and the clock.
• For end to end encryption, that means naming the host or bucket, the expected size, and the time the other side must have a complete file.
• A progress bar is not that record.
• A 200 response that arrives before the complete call is not that record.
• If a retry is allowed, say how many and whether it resumes.
• If a person must approve the send, name the person.
• Partners who receive end to end encryption files should match on hash or size before they import.
• A same-length corrupt file passes a size check and fails a hash.
• Keep the published hash off the only channel an attacker can edit, or treat it as a corruption check rather than a substitution check.
• When the path changes, new key, new region, new cap, update the profile the same day so the next run does not use a stale limit.