This applet is a reference implementation. It has not been through a Common Criteria evaluation or any third-party security audit, and it carries no certification. Known defects — including ones with security relevance — are published openly in docs/known-issues.md rather than held back.

Please read that document before reporting: if your finding is already listed, an issue adding detail or a patch is more useful than a private report.

The applet also assumes a deployment model that is worth stating plainly, because findings that depend on breaking it are not defects in the applet:

• It does not implement a secure channel. PINs and imported key material travel in the clear in the APDU data field. The applet is designed to sit behind GlobalPlatform SCP02/SCP03, or inside a SIM where the issuer security domain provides channel security.
• Padding is the host's responsibility. RSA signing and decryption are raw primitives, by design.
• PUK activation is unauthenticated on a virgin card, so that the card can be taken over during personalisation. This step belongs in a controlled environment.

Please do not open a public issue for a vulnerability that is not already listed in docs/known-issues.md.

Preferred: use GitHub's private vulnerability reporting — the Security tab of this repository, then Report a vulnerability. This keeps the report, the discussion and the eventual advisory in one place.

Alternative: email security@quantag-it.com. If you want to encrypt the report, say so in a first message without details and we will exchange keys.

Useful contents of a report:

• The command sequence that triggers it, ideally as an APDU trace
• The card platform and Java Card version, or the simulator version
• What an attacker gains, and what access they need to get there
• Whether the behaviour persists across card reset and applet deselect

We will tell you which of the two we are doing and why. Where a finding cannot be fixed without breaking the protocol, we will document it in docs/known-issues.md instead and say so.

Reporters are credited in the advisory and in CHANGELOG.md unless they prefer otherwise. There is no bug bounty.

The applet reports its own version via 80 70 00 00 00. Only the current main branch receives fixes; there are no maintained release branches.

If you have put this applet, or a derivative, on cards in the field, consider watching this repository so that advisories reach you. We have no way to identify downstream users and cannot notify you directly.