SPD Secure Vault

demo

Encrypt a secret in your browser, get a link. The ciphertext lives in the URL's #fragment — never sent to a server.

Passphrase

The only thing that opens the vault. Never leaves this tab.

Argon2id cost

Secrets pick a type per row · 🎲 generates one

adding a secret auto

secret

Argon2id

blob

link

Plays by itself. Lock a real vault on the left.

🔒Client-side onlystatic page, no API, nothing to breach
⚙️Tunable Argon2id128 MiB → 2 GiB, timed on screen
🏷️Typed entriestext · secret · number · json · date, validated
🎲Secret generator24-byte CSPRNG, one tap
🔗Link or QR.spd file for big vaults
🔍Inspectortime, size, bytes, algorithm chain
🧪Tamper testflip a byte, watch it get rejected
📲Installable PWAworks offline
🖥️Desktop buildnative Argon2id, reads/writes .spd

Passphrasechecked, never leaves the tab
Argon2id+ 256-bit salt → master secret
HKDF-SHA3-512split into cipher + MAC keys
XChaCha20-Poly1305per-entry; names encrypted too
Compress + HMAC-SHA3-512sign the whole blob → Base64
Into the URL #fragmentnever sent in the request
Unlock reverses itwrong pass or one flipped byte → fails first

Passphrase = the whole boundary. Link alone: useless. Link + passphrase: reads the vault. Send them separately.

Layer	Algorithm	Purpose
Key derivation	Argon2id (128 MiB–2 GiB)	Slow, memory-hard guesses
Key expansion	HKDF-SHA3-512	Domain-separated cipher + MAC keys
Encryption	XChaCha20-Poly1305	Per-entry AEAD, key commitment
Integrity	HMAC-SHA3-512	Any change to the blob is caught
Metadata	XChaCha20-Poly1305	Entry names encrypted, not just values
Post-quantum	ML-KEM-768 / ML-DSA-65	Where spd-lib does asymmetric work

Won't save you from: a weak passphrase, a compromised device, or someone holding both the link and the passphrase. Doesn't hide that a vault exists or its size.

Sending a credential in chatlink in Slack, passphrase out loud
Env config on day onea whole .env in one link
Laptop → phonelock, scan the QR, unlock
Secrets on support ticketsticket gets ciphertext, not the key
Cold storagea portable .spd file
Teaching cryptoinspector + tamper make it concrete

import { SPD } from "spd-lib/browser";      // pure JS, no Buffer, no fs

const spd = new SPD();
spd.setKeyProfile("standard");             // "high" | "paranoid"
await spd.setPassKey(passphrase);
await spd.addData("apiKey", "sk-live-…");
await spd.addData("config", { retries: 3 });

const blob = await spd.saveData(passphrase);            // Base64
const back = await SPD.loadFromString(blob, passphrase);
await back.extractData();                               // { apiKey, config }

Web + desktop share one vault-core.mjs — byte-identical .spd on both. spd-lib on npm ↗

Is anything uploaded when I lock a vault?

No. The page makes no network request during encryption. The link you copy is the only transport, and the ciphertext sits in its fragment — local to the browser.

What if I lose the passphrase?

The data is gone. No recovery, no reset — by design. Store a generated passphrase in a password manager before relying on it.

How big a vault fits in a link?

A few kilobytes comfortably. Past that the QR is skipped; well past that, use Download .spd and send the file.

Why is "Paranoid" slow in the browser?

2 GiB Argon2id in pure JS — intentionally expensive. The desktop build's native Argon2id is much faster.

Do the desktop app and website interoperate?

Yes. Same spd-lib v2 format. Links and .spd files cross both ways.

Production-ready?

It's a demo of the library and the share-by-fragment pattern. The crypto is real; the UX around it (no merging, rotation, or expiry) is deliberately minimal.

Passphrase

Secrets pick a type per row · 🎲 generates one

Someone shared a vault with you