# Sign in with qID

Post-quantum wallet login for BTX apps. No email. No password. The address is the account.

What WalletConnect is to EVM, qID Connect is to BTX. Except your login can never touch your coins, and there is no relay to go down.

Live with PQ Wallet for BTX v0.21 NIST FIPS 204 ML-DSA Independent audit pending
Get access Try to break it

## 01 One button in, session out

A user proves control of a BTX address by signing a one-time challenge with their wallet's post-quantum key. That address becomes their account. First sign-in is the registration. There is nothing else to collect and nothing to leak.

STEP 1 Your server issues a challenge

A fresh one-time nonce, bound to your exact origin, valid for five minutes.

STEP 2 The wallet shows and signs

The user sees which site is asking, picks an address, and signs with ML-DSA-44.

STEP 3 Your server verifies

The proof rebuilds the address cryptographically. Match means this user owns it.

STEP 4 Session

A signed HttpOnly cookie. The address is the user id. Done.

## 02 Three ways in, zero infrastructure

One dialog, three tabs. Scan with phone: the QR carries the challenge plus a proof address on your own server, the phone signs and posts it there, and the browser logs in by itself. Desktop wallet: copy the request, sign, paste the proof. Open in wallet: one click launches the installed desktop wallet, it signs and posts the proof, and the same poll logs you in. No relay service exists in this system. If every third party on earth is down, your login still works.

Scan with phone

WalletConnect feel, none of the relay. The site's own backend is the rendezvous, guarded by a secret only the signed-in browser holds.

Desktop wallet

Works today with the PQ Wallet for BTX, Settings, qID Sign-In. Copy in, proof out.

Open in wallet

One click into the installed PQ Wallet for BTX via btxqid://. It signs and posts the proof; the dialog picks the session up on the same poll.

## 03 Safe by construction

A sign-in can never move funds.

Login proofs are signed in a separate cryptographic domain from transactions. The two cannot collide, so the worst a fully malicious website can ever obtain is a single-use login proof for its own origin. No approval screens to misread, no allowances to revoke, no drain risk to explain away. This is structural, not a policy.

Claims we make and none we do not: resistant to quantum attacks, built on NIST-standardized post-quantum cryptography, pending independent audit.

## 04 What builders do with it

Pure wallet accounts

Register and log in with only an address. The demo app has no email field anywhere, on purpose.

Ownership proof

Sellers, OTC desks, and support flows verify an address belongs to the person in front of them.

Gated communities

Sign in proves the address, the chain shows what it holds. Token and artifact gating with zero custody.

Your wallet, qID compatible

Building a wallet? The signer SDK and the rules are available to wallet builders on request.

## 05 The phases

Power arrives in order of safety. Each phase is complete and safe even if no later phase ever ships.

1. Sign in

Connect, prove, log in. No transaction surface exists in this phase at all.

2. Hardened keys

Auth-only keys that structurally cannot spend, key rotation, revocation.

3. Mobile live connect

On top of the live scan and one-click connect: persistent visible sessions and revoke-anywhere.

4. Payment requests

Gated behind independent audits. The wallet builds its own transactions, always. It ships when it is boring.