UNDER THE HOOD

qID

qID is the post-quantum identity and signing engine inside BTX Wallet. It derives your keys, builds your address, signs your spends, and proves who you are — all on your own device, using cryptography standardized to outlast a quantum computer.

It is the key infrastructure the wallet is built on. Proprietary today; the standards and the verification are public, and live on this page.

Post-quantum signing

A fast lattice signature (ML-DSA-44) for everyday spends and login, and a conservative hash-based signature (SLH-DSA-SHAKE-128s) as the recovery root. Two different mathematical foundations, so they do not fall together.

On-chain BTX

Builds btx1z P2MR outputs and signs spends the BTX node accepts byte-for-byte — the same key derivation and address construction as the chain itself.

Passwordless login

Sign a one-time challenge to prove you hold the key. Off-chain identity with no password, no account, and no server to trust.

Encrypt to an identity

ML-KEM-768 key exchange lets data be encrypted to a public identity and opened only by the holder of its key — post-quantum confidentiality, not just signatures.

Rotation and recovery

The hash-based recovery key is the stable root of your identity. It attests to your login and encryption keys, so the everyday key can rotate without changing who you are.

On-device, deterministic

Every key descends from one 256-bit master seed, derived locally. qID runs entirely on your machine and never transmits a key.

SPECIFICATIONS

Standards and primitives

qID uses only NIST-standardized post-quantum primitives, implemented on the independently audited noble and scure cryptography libraries.

Recovery root SLH-DSA-SHAKE-128s FIPS 205 · hash-based

Encryption (KEM) ML-KEM-768 FIPS 203 · lattice

Address P2MR · btx1z bech32m · witness v2

Master key 256-bit seed deterministic derivation

Built on noble / scure audited · zero-dependency

VERIFICATION

Checked, not claimed

NIST known-answer tests. Key generation for all three algorithms is checked against the official FIPS 203 / 204 / 205 ACVP test vectors.
Node-verified. From the standard test seed, qID derives an address byte-identical to the BTX node, and the full spend lifecycle (build, broadcast, mined) is exercised on a regtest network.
Independently reviewed. An adversarial code review found the signing path fund-safe, with no critical or high findings.
Pinned and gated. Address derivation and the transaction sighash are pinned as offline regression vectors, and a build-reproducibility check runs in CI, so a behavior change cannot slip in unnoticed.

Byte-exact to the BTX node — standard test seed 0102…20 btx1ze43r7pvqfld9guktkqnru2ca4dedpzw4xaahx2ardt3vwt5pw5kssu5f7r

ASSURANCE

Safe by construction

Honest amounts. Each input's signature commits to the amount being spent, so a server that lies about your coins cannot trick a signature into overpaying.
Bounded fees. Fee-rate limits are enforced in the signing layer, with a relay-minimum floor and a sane ceiling.
Crypto-agility. Because the recovery root is hash-based and the spend key is lattice-based, the two rest on independent assumptions — a break in one does not break the other.
Keys stay home. qID derives and signs entirely on-device. The wallet that embeds it seals those keys at rest with Touch ID, Windows Hello, or a passphrase; qID itself never sends a key anywhere.

CHANGELOG

What changed, and when

2026-06

Hardening

Offline regression vectors for address derivation and the transaction sighash, plus NIST ACVP keygen vectors, were pinned into the test suite. Added a relay-minimum fee-rate floor, zeroized intermediate key-derivation buffers, and a CI test with a build-reproducibility gate. Independently code-reviewed and found fund-safe.

2026-05

Send core

Multi-input P2MR coin selection, sweep, and signing with per-input sighash commitments. Verified end to end on a regtest network: transactions built by qID broadcast and mine. Security-audited.

2026-05

Initial

Post-quantum identity: ML-DSA-44 and SLH-DSA-SHAKE-128s keys derived from one seed, ML-KEM-768 encryption, and P2MR btx1z addresses byte-exact to the BTX node, with login, attestation, and key rotation.

Built into BTX Wallet

qID ships inside every copy of BTX Wallet. There is nothing extra to install — download the wallet and qID is already protecting your keys.

Download BTX Wallet How the wallet works Wallet changelog

Not open source, yet

qID is proprietary key infrastructure that powers BTX Wallet. The source is not public today, and we may open it in the future. The standards, capabilities, and verification on this page are documented so you can see exactly what protects your keys, even while the implementation stays private.