Key Architecture
BlackVault separates the keys that sign transactions from the keys that power privacy — and the privacy keys are derived on demand, never stored.
The key hierarchy
The keys, one by one
Wallet key (custody)
Your embedded-wallet private key — the one that signs every transaction and that you can export any time. Created at sign-in via distributed key infrastructure; usable only from your authenticated session. This is the key that makes BlackVault self-custodial.
Stealth identity (derived)
A single deterministic signature from the wallet key seeds your stealth identity. Because it’s derived, it never needs storing — reload the app, re-sign, and the exact same identity comes back.
Spending keypair
Controls the money. The private spending key derives the one-time private key for each incoming payment, which is what actually spends funds swept from a stealth address. Whoever holds it controls your private balance.
Viewing keypair
Controls detection. The private viewing key lets you scan ERC-5564 announcements and recognize which one-time addresses are yours — without the ability to spend. This is the key you could hand an auditor for read-only proof, without giving up control of funds.
Per-payment one-time keys
For each payment, the sender’s fresh ephemeral key + your viewing key produce a
unique address P; your spending key derives P’s private key at claim time.
New key per payment ⇒ every payment is unlinkable.
Where keys live
| Key | Storage | Lifetime |
|---|---|---|
| Wallet key | Managed by the embedded-wallet session | Persistent · exportable |
| Stealth identity | Nowhere at rest | Re-derived each session from a signature |
| Spending / viewing | In-memory during the session | Cleared on close, re-derived on demand |
| One-time keys | Computed at claim time | Ephemeral |
Only public scan progress (block cursors, matched public addresses) is persisted — never key material. Clearing your browser costs you nothing but a re-sign.
Why this matters
- Nothing sensitive at rest — a stolen device disk yields no stealth keys.
- Read/spend separation — you can prove receipt (viewing) without exposing spend authority.
- Deterministic recovery — your privacy identity is recoverable from your wallet alone, no extra backup to lose.