Sample DER certificate for testing parsers — free, CC0

DER is the binary encoding of an X.509 certificate: the form a parser actually meets inside a TLS handshake, a Java keystore or a certificate store, as opposed to the base64 text that gets pasted into configuration files.

der/self-signed-ed25519-cert.der is a self-signed Ed25519 certificate for the reserved name fixture.example, valid from 2020 to 2120 with a fixed serial number. It is byte for byte the same certificate as the PEM fixture, just without the armour, so you can use the pair to test that your code converts between the two encodings correctly.

The key is derived from a published seed, which means anyone can rebuild the certificate and confirm it is what it claims to be. No private key is published, and the certificate names only a reserved example domain, so it cannot be mistaken for a credential for a real host.

Use it to test certificate parsers, keystore importers and anything that has to detect the encoding it was handed. Related format: PEM.

curl -O https://loremfile.dev/der/self-signed-ed25519-cert.der

<a href="https://loremfile.dev/der/self-signed-ed25519-cert.der">download</a>