Deterministic Password Manager

What you can build

A password manager with no vault: each service’s secret is derived from the user’s seed phrase and that service’s name — the same result on every device, forever, and never persisted anywhere. A new phone plus the twelve words restores every password.

How it works

A Handle per persona derives one secret per service context:

const work = await identity.deriveHandle('work');
const githubSecret = work.derivePassword('github.com', 32);
const jiraSecret   = work.derivePassword('jira.internal', 32);

@me2em/crypto adds the guard rails: Argon2id profiles for secrets a user must type rather than derive, and HIBP breach checks for the rare hand-chosen password.

Benefits

• Zero storage. No vault file, no cloud sync, no breach surface — the password exists only at the moment of use.
• Deterministic restoration. Same seed + same context → same secret, on every device, with nothing to sync.
• Per-context isolation. A compromise of the work Handle never derives the personal Handle’s secrets.
• No reset flows. No “forgot password” exists because no password is stored.

Trade-offs

• The seed is the single point of failure. Lose the phrase — every derived password is gone; there is no recovery by design.
• Rotation is structural. Changing a secret means changing its context name — plan per-service rotation instead of in-place updates.
• Alpha. Package APIs are pre-1.0; pin versions.

References

• Scenario 8 in the protocol Use Cases guide
• Blog post why we don’t store your seed — the zero-storage model
• Blog post a password manager that stores nothing