Security

Your authentication secrets deserve stronger protection.

NexKey is designed so that normal OTP generation happens directly on your device. This page describes what that means in practice, and where the trust boundaries sit.

Security overview

Two properties shape the design: codes are generated locally, and anything that leaves your device is encrypted before it does.

  • Local OTP generation

    Codes are computed on-device from the stored secret and the current time or counter.

  • Platform-secure secret storage

    iOS and macOS Keychain, Android Keystore. Secrets are never written to plain files.

  • Touch ID / Face ID protection

    Biometric unlock gates access to the vault; the OS enforces it.

  • End-to-end encrypted sync

    Encryption happens before upload with a device-held key.

  • Trusted device approval

    New devices join only after approval from an existing trusted device.

  • No plaintext OTP secrets in the backend

    The server stores ciphertext and metadata it cannot decrypt.

Storage and biometrics

Keychain and Android Keystore

Authenticator secrets are held in platform secure storage rather than in plain application files, so they are protected by the operating system's own key management.

KeychainSecure EnclaveAndroid Keystore

Biometric protection

Access to the authenticator can be gated behind the platform biometric check, so codes are revealed only after it succeeds.

Touch IDFace IDAndroid biometrics

Encrypted synchronization

Sync is optional. When it is on, your vault is encrypted on your device before upload and decrypted only on devices you have trusted.

  1. iPhone Secrets live in the Secure Enclave–backed Keychain.
  2. Encrypt locally Vault is encrypted with a key that never leaves the device.
  3. Encrypted Vault Backend stores ciphertext. It has no key to read it.
  4. Trusted Mac Only devices you approved hold a decryption key.
  5. Decrypt locally Plaintext exists only in memory on the trusted device.
Encrypted on device Ciphertext in cloud Decrypted on trusted device

Trust boundaries

Where data is readable, and where it is not.

Trusted device model

Every device is enrolled explicitly. You can review the list and revoke any device, which stops it receiving further synchronized data.

Backend trust boundary

The NexKey backend transfers and stores ciphertext. It does not hold readable OTP secrets and does not generate codes on your behalf.

Secure clipboard handling

Copied codes are short-lived: NexKey clears the clipboard entry after a short interval so a code does not linger there.

No plaintext logging

OTP secrets and generated codes are treated as sensitive and excluded from application logs and diagnostics.

Works offline

Because generation is local, an unavailable backend does not stop you signing in anywhere.

This website

nexkey.app is a marketing site. It contains no OTP implementation, accepts no authenticator secrets, and stores nothing in your browser.

Open standards

NexKey implements published specifications so its behaviour can be checked against them.

RFC 6238 TOTP Time-based one-time passwords, 30-second default period. Read the specification
RFC 4226 HOTP Counter-based one-time passwords. Read the specification
RFC 4648 Base32 Secret encoding used by otpauth provisioning. Read the specification
otpauth:// QR Provisioning Standard URI scheme encoded in setup QR codes. Read the specification
SHA-1 Default digest The digest most services still issue for TOTP secrets.
SHA-256 Extended digest Supported for services that issue stronger digests.
SHA-512 Extended digest Supported for services that issue stronger digests.

Responsible disclosure

Reporting a security issue

If you believe you have found a vulnerability, email us with the details and any steps to reproduce. Please give us a reasonable window to investigate and ship a fix before disclosing publicly.

We will acknowledge your report, keep you updated while we investigate, and credit you when a fix ships, if you would like us to.

One key. Every device.

Secure your accounts with NexKey on mobile and Mac.

  • iPhone · Coming soon
  • Android · Coming soon
  • macOS · Coming soon