Verify a public package#

This tutorial verifies a real package from a public Prefix.dev channel. It does not require a channel account, signing identity, or package build.

Prerequisites#

You need:

conda sigstore from the installation guide
curl, or PowerShell’s Invoke-WebRequest

1. Download the package and its evidence#

Create a working directory and download the fixed public example.

Linux and macOS

mkdir conda-sigstore-tutorial
cd conda-sigstore-tutorial
curl --fail --location --remote-name \
  https://prefix.dev/sigstore-example/linux-64/signed-package-2.1.0-hb0f4dca_0.conda
curl --fail --location --remote-name \
  https://prefix.dev/sigstore-example/linux-64/signed-package-2.1.0-hb0f4dca_0.conda.v0.sigs

PowerShell

New-Item -ItemType Directory -Path conda-sigstore-tutorial
Set-Location conda-sigstore-tutorial
Invoke-WebRequest `
  -Uri https://prefix.dev/sigstore-example/linux-64/signed-package-2.1.0-hb0f4dca_0.conda `
  -OutFile signed-package-2.1.0-hb0f4dca_0.conda
Invoke-WebRequest `
  -Uri https://prefix.dev/sigstore-example/linux-64/signed-package-2.1.0-hb0f4dca_0.conda.v0.sigs `
  -OutFile signed-package-2.1.0-hb0f4dca_0.conda.v0.sigs

The .conda file is the package. The .v0.sigs file is a JSON array of Sigstore bundles served next to it by Prefix.dev.

2. Verify the package#

Verify both local files and supply the channel claimed by the publication statement:

conda sigstore verify signed-package-2.1.0-hb0f4dca_0.conda \
  --bundle signed-package-2.1.0-hb0f4dca_0.conda.v0.sigs \
  --channel https://prefix.dev/sigstore-example

The first line should end in verified. The evidence includes these values:

Predicate      https://schemas.conda.org/attestations-publish-1.schema.json
Identity       https://github.com/prefix-dev/sigstore-example/.github/workflows/action.yaml@refs/heads/main
Issuer         https://token.actions.githubusercontent.com
Target channel https://prefix.dev/sigstore-example

Here, the predicate names the kind of signed claim. The issuer is the service that issued the signer’s OpenID Connect credential. The command exits with status 0 because at least one valid CEP 27 publication statement binds the exact filename and SHA-256 to the supplied channel.

3. Inspect machine-readable output#

Run the same verification with JSON output:

conda sigstore verify signed-package-2.1.0-hb0f4dca_0.conda \
  --bundle signed-package-2.1.0-hb0f4dca_0.conda.v0.sigs \
  --channel https://prefix.dev/sigstore-example \
  --json

The top-level status is verified. The evidence array contains the signer, issuer, predicate type, timestamp, and target channel. Read JSON output and exit status before consuming the result from another program.

What you verified#

Sigstore authenticated the reported workflow identity. The CEP 27 statement bound that signature to the downloaded package and claimed channel. The result does not establish that Prefix.dev authorized that workflow to publish the package and does not assess whether the package is safe to run.

Next, sign a package, verify during installation, or audit an installed environment.