Messages sealed the moment they're sent.
Hashmesh is a calm, instrument-plain messenger for small groups. Every message you send is folded into your conversation's hash chain, so the history you read back is provably the history that was written.
Room is up — say hi when you're in.
sealed0x7f3a1c…c1d2 ← 0x0000…seed
Here. This chain thing is oddly satisfying.
sealed0x9be0f2…44aa ← 0x7f3a1c…c1d2
Try editing one and watch it break.
sealed0xd12c88…0f7e ← 0x9be0f2…44aa
How a conversation gets sealed
Create your account
Sign up with an email and password. You land straight in your authenticated messenger — no waiting on a confirmation email.
Create or join a named conversation
Type a conversation name. If it already exists you join it; if it doesn't, you start it and seed its chain.
Send — and return later
Every message you send is sealed into that chain. Sign out, sign back in, and your conversations and messages are waiting.
What “sealed” actually means here
We'd rather under-claim than over-claim. Here is exactly what the seal does and does not do.
- What it does
- Each message's seal is a SHA-256 hash of its text, sender, and the previous seal. Change, delete, or reorder a past message and every seal after it stops matching — tampering becomes visible instead of silent.
- What it doesn't do
- This is tamper-evidence, not end-to-end encryption. Message text is stored in the conversation's database record so members can read history back; it is not hidden from the service operating that database.