April 1, 2026
Label it or get duped
You're still signing data structures the wrong way
Dev brawl over “label your messages” fix: brilliant or just déjà vu
TLDR: A new proposal says to attach a unique label to every message so signatures can’t be misused on the wrong thing. Commenters split: some say this is old news with simpler fixes, others want labels baked in, and veterans joke it’s 1980s tech reborn—important because real systems have been burned by this mix‑up.
A new post says we’ve been signing data the wrong way and proposes a fix: bake a unique “label” into each message type so a signature can’t be reused on something else. Think of it like writing the dish name on a casserole—no more mixing up lasagna with dessert. The idea (from FOKS’s “Snowpack”) sparked a comment-section cage match.
Fans say it’s clean and hard to mess up. Skeptics rolled their eyes hard enough to power a data center. formerly_proven declared the problem solved ages ago: just sign the raw bytes and include secret context that never gets sent—classic best practice. Retr0id countered with a pragmatic take: forget fancy compilers, “put the type in the message itself” so everyone can see it. Meanwhile, tantalor dropped a practical “do it in protobuf options” recipe, and the old guard, led by Muromec, joked that we just reinvented 1980s tech like ASN.1 and should probably slap a version number on everything while we’re at it.
The stakes aren’t imaginary—mix-ups like this have burned projects from Bitcoin to TLS. One commenter even warned you can get a legit-looking email the sender never sent, proving why labeling matters. The vibe? Equal parts “finally,” “already solved,” and “lol we’re back to square one.”
Key Points
- •The article identifies two key requirements for secure cryptographic preprocessing: canonical encoding and domain separation.
- •A protobuf example shows how two different message types with identical field layouts can serialize identically, enabling signature misinterpretation attacks.
- •Such type-confusion attacks have real-world precedents in systems like Bitcoin, Ethereum DEXs, TLS, JWTs, and AWS.
- •Prior domain separation techniques are ad hoc (e.g., Solana method names, Ethereum best practices, TLS 1.3 context strings), motivating a systematic solution.
- •The proposed Snowpack approach embeds random, immutable 64-bit domain separators in the IDL; code generation and type systems (e.g., in Go/TypeScript) enforce prepending these IDs before signing, verifying, MAC’ing, hashing, or encrypting.