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Your data & security

Brainstorm’s security model exists so you can run apps and agents over your most important knowledge without giving anything ambient access to it.

A key only you hold

Section titled “A key only you hold”

Each vault is protected by a master key that never leaves your machine in plaintext. You choose where it’s stored:

  • in your operating system keychain, or
  • derived from a passphrase you supply.

The key is held in memory only while the vault is open and is wiped when you close it. There’s no Brainstorm account that can unlock your vault for you — and equally, no one else can.

Your identity

Section titled “Your identity”

Each vault carries a cryptographic identity — a keypair that signs the changes you make. Collaborators can verify that an edit genuinely came from you, and your private signing key never crosses an app boundary or leaves the device. When you share an object, people appear by name with their key fingerprint beside it — the fingerprint, not the name, is what tells two people apart.

The sandbox and the ledger

Section titled “The sandbox and the ledger”

Apps are sandboxed and isolated from each other and the system. Everything sensitive an app can do is mediated by the capability ledger, which fails closed: if a permission can’t be confirmed, the action is denied. There’s no path by which an app quietly gains access you didn’t grant.

Apps you install yourself — from your vault, a folder, or a .brainstorm bundle — are unsigned, so they’re marked as such and held to a stricter sideloaded trust tier: they get the capabilities you grant and nothing more.

Encryption at rest and in transit

Section titled “Encryption at rest and in transit”
  • In transit: when you sync, content is end-to-end encrypted before leaving your device; the relay can’t read it. See Local-first & sync.
  • At rest: your vault is stored locally under your control, protected by your master key.

What Brainstorm does not do

Section titled “What Brainstorm does not do”
  • It does not phone your content home. There is no server that holds your vault.
  • It does not give apps blanket access “to be convenient.”
  • It does not lock your data in a proprietary format — your knowledge is structured, portable, and yours.

Next steps

Section titled “Next steps”