Stop on invalid or incomplete content
06Authenticated records do not remove the need for whole-message checks, safe key usage, trusted application policy and protection of visible metadata.
An attacker able to replace both Content-Encoding and the body could substitute unencrypted content. A recipient that depends on this mechanism for content-origin authentication MUST reject missing aes128gcm. Header privacy, storage authorization, size/timing and key distribution remain separate concerns.
Source for this drawing: RFC 8188 · Read RFC section 4.2 ↗
New to this? Start hereA quick picture + helpful background
A message needs an address.
Think of a packet as a small addressed envelope. Devices pass it onward; transport protocols decide what delivery promises an application gets.
Helpful first, if these ideas are unfamiliar
These pictures are analogies to help you learn. The linked RFC explains the actual rules.
Terms in this drawing
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
A partially delivered message MUST NOT be treated or cached as a complete message. Streaming applications must avoid attacker-beneficial intermediate processing states.
- A partially delivered message MUST NOT be treated or cached as a complete message. Streaming applications must avoid attacker-beneficial intermediate processing states.
- Reusing IKM and salt for a new application reuses the key/nonce sequence and is unsafe. With reused IKM, salt MUST be unique each time; a random salt per message is a SHOULD.
- Total plaintext under one derived key MUST stay below 2^44.5 blocks of 16 octets (§4.4). This guide does not implement a global usage tracker.
- Recipients relying on content-origin authentication MUST reject a message missing aes128gcm. HTTP fields, size and timing can leak information; padding is not a complete anonymity defense.
Published test keys are examples, not secrets to use. This guide does not implement key management or a production cryptographic library.
Read the RFC section ↗