Keys
How one recovery phrase produces every key Sombra uses, and what each of them can do.
You write down 24 words once. Every key Sombra uses is derived from them, so there is nothing else to back up and nothing else to lose.
This page is for the curious. You do not need any of it to use the wallet.
One phrase, six keys
| Key | What it does |
|---|---|
| Spend key | Owns your notes. Proving you hold it is what authorises a payment. |
| Nullifier key | Marks a note as spent, so the same note cannot be used twice. |
| Viewing keys | Decrypt notes sent to you. One per week. |
| Outgoing keys | Decrypt your own record of what you sent. One per week. |
| Auth key | Identifies your wallet to Sombra's services. |
| Solana key | Pays network fees. It can never move your shielded balance. |
The split matters. A viewing key reads; it cannot spend. So you can give someone the ability to audit your account without giving them the ability to touch it.
How they come out of the phrase
Your 24 words become one 256-bit secret. That secret goes through a one-way hash function, once per key, each time with a different label.
One-way is the whole point. A viewing key cannot be turned back into your phrase, and it cannot be turned sideways into your spend key. Handing one out gives away exactly what that key does and nothing more.
The Solana key is derived on its own path, the standard one every Solana wallet uses, so the same phrase gives you the same public address anywhere.
Why viewing keys are weekly
Instead of one viewing key forever, Sombra derives one per week, from a tree that covers 8192 weeks — about 157 years.
That turns "can you look at my account?" into a question with a bounded answer. You hand over the weeks you mean, say a single tax year, and the keys for every other week stay out of reach. One key forever would have been all or nothing.
Outgoing keys work the same way, which is why a restored wallet gets back the payments you sent, not only the ones you received.
Your address
Your shielded address is a short string that starts with somb — or tsomb on the test networks, which is what you will see today. It carries what someone needs to encrypt a note to you, and nothing that lets them spend one.
Sharing it is safe. It reveals no balance and no history.
What to protect
The 24 words. That is the whole list.
Anyone with them has your money. Nobody at Sombra can recover them for you, and nobody can reset them. Write them down somewhere physical, and never type them into a page that asks for them.
Next: Security — what the protocol protects, and what it does not.