Verify a release

Alongside the binary tarballs, each release ships SHA256SUMS (the manifest) and SHA256SUMS.sig (its Ed25519 signature). All artifacts, plus the signing key, are attached to each GitHub release; /public/ indexes the releases and the machine-readable manifest.

Already running magus? Use the built-in verifier:

magus self update --dry-run

The trust chain runs through your already-trusted binary. Nothing else to do.

First install - verify by hand. Do not verify a fresh magus with itself: a tampered build carries the attacker's key and self-reports success. Use OpenSSL with the key served from this HTTPS page.

1. Save the key. Either download magus-release.pem, or copy the PEM block below into magus-release.pem.

2. Verify the manifest signature (requires OpenSSL 3.0+):

   openssl pkeyutl -verify -pubin -inkey magus-release.pem \
     -rawin -in SHA256SUMS -sigfile SHA256SUMS.sig
   # Signature Verified Successfully
   

3. Only if the signature verifies, check the artifact hash:

   sha256sum --ignore-missing -c SHA256SUMS
   # macOS: shasum -a 256 --ignore-missing -c SHA256SUMS
   

   --ignore-missing skips manifest entries for artifacts you did not download, so the output stays limited to the file you fetched - without piping through grep, which would replace the command's exit status with grep's and let a failed check report success.

Order matters. Checking a hash against an unverified manifest proves nothing. The whole procedure in one picture - each merged cell consumes everything beside it, and the tarball deliberately skips the first step, because nothing signs the tarball directly:

Release signing key (Ed25519)

-----BEGIN PUBLIC KEY-----
MCowBQYDK2VwAyEA/7uPpvNidN79EoiAk8ajIsJTK8VFAW9JWrSVXey2Z3k=
-----END PUBLIC KEY-----

Raw base64 (32 bytes):

/7uPpvNidN79EoiAk8ajIsJTK8VFAW9JWrSVXey2Z3k=

The key is embedded in every magus binary via //go:embed, so magus self update trusts it transitively. A planned rotation first ships a release signed by the current key that embeds the replacement key; later releases can use the replacement. Older binaries cannot be remotely revoked if the current key is compromised. The maintainer procedure is in the contributing guide.