in-toto-sign

Sign 'unsigned.layout' with two keys and write it to 'root.layout'

$ in-toto-sign [[-f|--file]] [unsigned.layout] [[-k|--keep]] [priv_key1] [priv_key2] [[-o|--output]] [root.layout]

$ in-toto-sign [[-f|--file]] [package.2f89b927.link] [[-k|--keep]] [priv_key]

$ in-toto-sign [[-f|--file]] [root.layout] [[-k|--keep]] [pub_key0] [pub_key1] [pub_key2] --verify

$ in-toto-sign [[-f|--file]] [root.layout] [[-g|--gpg]]

$ in-toto-sign [[-f|--file]] [root.layout] --verify [[-g|--gpg]] [...439F3C2]

in-toto-sign [-h | --help] [--version] [--key KEY] [--key-type {rsa,ed25519}] [--hash-algorithm {sha256,sha384,sha512}] [--normalize] ARTIFACT

-h, --help
    Show help message and exit.

--version
    Show program's version number and exit.

--key KEY
    Path to PEM private key file for signing (or use IN_TOTO_SIGN_KEY env var).

--key-type {rsa,ed25519}
    Asymmetric key type for signing.

--hash-algorithm {sha256,sha384,sha512}
    Hash algorithm for signature computation (default: sha256).

--normalize
    Canonicalize layout fields before signing (default: false).

in-toto-sign is a command-line tool from the in-toto project for cryptographically signing supply chain security metadata, including layouts, links, and statements. These artifacts attest to actions in software supply chains, and signatures ensure their authenticity and integrity against tampering.

The tool loads a private key (RSA or Ed25519), reads the JSON artifact file, optionally normalizes layouts, computes a signature over the canonicalized content using a specified hash algorithm (SHA256, SHA384, or SHA512), and appends the signature in the standard in-toto format. The original file is modified in place.

It supports key files in PEM format and can use the IN_TOTO_SIGN_KEY environment variable as a fallback. Signed artifacts are verifiable with tools like in-toto-verify, enabling trusted verification of supply chain steps from materials to deployment.

This utility is vital for supply chain participants (e.g., builders, testers) to produce verifiable attestations, aligning with SLSA and other frameworks for securing CI/CD pipelines.

Modifies artifact file in place; backup recommended. Requires valid private key access. Only signs supported artifact types (layouts, links, statements).

in-toto-sign --key private.pem link.json
in-toto-sign --key-type ed25519 --hash-algorithm sha512 --normalize layout.json

Supports unencrypted PEM keys. Ed25519 for efficiency, RSA for compatibility.

Part of the in-toto project, launched in 2017 by NYU, IBM, and Google researchers to secure software supply chains. Evolved with SLSA framework integration; current versions in python-in-toto package.

in-toto-run(1), in-toto-verify(1), in-toto-layout-to-json(1)