Certainly Something (Certificate Viewer)
Uses the new TLS Info API in Firefox to view information about the current state of your HTTPS connection.
It currently requires at least Firefox 62.
Developing and Installing Locally
It is recommend that developers use web-ext for installation and testing. It provides a number of useful features, such as automated installation and autoreload upon source changes.
Install web-ext using the following command:
$ npm install --global web-ext
For testing and development, run the following commands in two separate terminal windows:
$ npm run-script watch $ web-ext run --browser-console -s build --start-url 'https://badssl.com/'
If you are simply looking to give it a single run, you can compile it by running:
$ npm install $ npm run-script compile
And then in Firefox, go to -> Add-ons -> Extensions -> (Gear Icon) -> Debug Add-ons -> Load Temporary Add-on
build/manifest.json and it should start running immediately.
- Handshake information (TLS version, cipher suite, signature scheme)
- Subject and issuer information (common name, organization, etc.)
- Validity date ranges
- Subject alternative names
- Subject public key information (SPKI)
- Certificate downloading
- Key usage
- Serial numbers
- Extensions, including
- Basic constraints
- Extended key usage
- Certificate revocation list (CRL) endpoints
- Authority information access (AIA)
- Certificate policies (most common policies)
- Subject key identifiers
- Authority key identifiers
- OCSP stapling
- Embedded SCTs, including CT log names