Every analysis log is signed, so the first thing to establish about any result is whether its signature is still valid. Do this before reading the numbers, particularly for a result somebody else produced.
In-application verification
Signature status is shown on each result card in the Import Result tab, and in the Info tab of an imported analysis. Verification is automatic; there is nothing to trigger.
| Icon | Status | Meaning | What to do |
|---|---|---|---|
| Lock, green | Valid | Signature verified, including the non-repudiation signature if present | Proceed |
| Shield-cross, red | Tampered | The content changed after signing | Do not rely on it. Obtain the original, or rerun the analysis |
| Warning, orange | Unknown Key | Signed with a key this build does not recognize | Usually a log from a newer release than the application reading it. Update and retry |
| Warning, orange | Non-Repudiation Invalid | The primary signature is valid but the BYOK signature failed | The file is intact and produced by MTC Skopos, but the organizational signature does not verify. Check the BYOK key configuration |
| Lock-open, grey | Unsigned | Produced before log signing existed | Not evidence of tampering, but it carries no integrity guarantee either |
A green lock covers two distinct claims: that the content is unchanged, and that an authentic copy of MTC Skopos produced it. It does not by itself prove which organization ran the analysis. That is what BYOK adds. See How Log Signing Works.
Exporting public keys for auditors
Auditors verifying a log without MTC Skopos need the public key it was signed with.
- Click ? > Export log signing public keys
- Select a destination directory
- The embedded
mtc-*.pubfiles are written there
These are public keys and safe to share by any channel. Send them with the log files and the independent verification instructions.
Several mtc-*.pub files may be exported. Embedded keys rotate between releases, older public keys are retained so older logs stay verifiable, and the key_id field in each log names the key that signed it. Give auditors all of them rather than trying to work out which one applies.
If BYOK is configured, auditors also need your own public key, which is not part of this export because MTC Skopos never holds it. See Bring Your Own Key.
What a valid signature does not tell you
The signature protects integrity and origin. It says nothing about whether the analysis was scoped sensibly. A validly signed log of a run restricted to one department is genuine evidence of very little, so read the recorded criteria alongside the signature. The IT Auditor Verification Guide covers the full checklist.