Explanation¶

Understanding-oriented material: what sigillum is, how it is put together, the reasoning behind those choices, and where the edges are.

sigillum is a standalone signing CLI. It owns almost no logic of its own — it wires together upstream modules and ships the signing backends. That thinness is deliberate, and the pages below explain why.

• Components & architecture — the module stack (sigillum → go/signing-cli → go/signing + backends) and how the pieces fit together.
• Concepts — why sigillum exists as a separate tool from gtb, and the build-time backend blank-import model.
• What sigillum does not do — the limits. No verify command, no key algorithm that serves both signature formats, no encrypted private keys, no runtime backend selection, no configurable signing.

Where should I start?¶

• If you are trying to decide whether sigillum fits your pipeline, read Concepts and then What sigillum does not do.
• If something failed and you want to know whether it is meant to, What sigillum does not do lists the refusals with their exact error messages.
• If you are changing the code or adding a backend, Components & architecture has the module boundaries.