To avoid impersonation each message should be signed #17

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1. bourgeoa

   changed the title [-]To avoid impersonation each message should be verified[/-] [+]To avoid impersonation each message should be signed[/+] on Jan 10, 2026
2. melvincarvalho commented on Jan 15, 2026

   

   melvincarvalho

   on Jan 15, 2026

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   Thanks for raising this! Message signing is definitely important for preventing impersonation.

   Since you implemented the original in SolidOS, I'd love your feedback on porting it to solid-chat/app. Here's my understanding of the approach:

   Implementation Sketch (based on SolidOS)

   1. Use Schnorr signatures (secp256k1)

   import { schnorr } from '@noble/curves/secp256k1'
   import { sha256 } from '@noble/hashes/sha256'

   2. Sign on send

   const msg = { id: msgUri, created: timestamp, content: text, maker: webId }
   const hash = sha256(JSON.stringify(msg))
   const sig = schnorr.sign(hash, privateKey)
   
   ins.push($rdf.st(msgNode, SEC('proofValue'), sig, doc))

   3. Verify on render

   const signature = store.any(msgNode, SEC('proofValue'))
   const publicKey = await getPublicKey(makerWebId)
   const valid = schnorr.verify(signature, hash, publicKey)
   
   if (!signature) messageRow.style.background = 'red'  // unsigned

   4. Key storage

   <#me> solid:publicKey "HEX_PUBLIC_KEY" .  # world-readable
   <#me> solid:privateKey "HEX_PRIVATE_KEY" . # owner-only ACL

   Is this the right approach? Any gotchas or lessons learned from the SolidOS implementation we should know about?

   (We have more detailed analysis in #18 including security concerns)
3. bourgeoa commented on Jan 15, 2026

   

   bourgeoa

   on Jan 15, 2026

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   Any gotchas or lessons learned from the SolidOS implementation we should know about?

   • the key management system never broke but use is not high
   • there is no incentive for a user to delete the private key.
   • if missing the public key is automatically recreated by the chat-app when an owner use the SolidOS chat
   • security side is in my opinion high enough due to it's usage : only in chat even private only

   The main issue is the key creation/re-creation that is SolidOS chat dependant.

   A better way would be SolidOS dependant. But where ?
   I was thinking to solid-logic near authentication.
   The draw back is that only SolidOS user can create the key.
   I don't think it is a good idea to have it created by any app.