MediaSigner

MediaSigner packages the asynchronous Signer facade that orchestrates registered SigningBase providers. Moving the facade into a standalone plugin keeps the core standards library lightweight while still enabling drop-in discovery of specialised signers such as CMS, JWS, OpenPGP, PDF, and XMLDSig providers.

Features

• Unified signing façade – talk to every installed SigningBase through a single async API that automatically discovers entry-point contributions.
• Format-aware routing – delegates signing and verification to the provider registered for a format token such as jws, pdf, or xmld.
• Optional plugin bundles – install curated extras (e.g. [plugins]) to bring in all available signer backends in one step.
• Key-provider integration – share Swarmauri key providers with the facade so opaque key references resolve before signature creation.
• Production-ready CLI – inspect capabilities, sign payloads, and verify results directly from the command line for fast automation.

Installation

Using uv

uv add MediaSigner

# install every optional backend
uv add "MediaSigner[plugins]"

The [plugins] extra pulls in CMS, JWS, OpenPGP, PDF, and XMLDSig signers.

Using pip

pip install MediaSigner

# with every optional backend
pip install "MediaSigner[plugins]"

Usage

import asyncio

from MediaSigner import MediaSigner
from swarmauri_core.key_providers.IKeyProvider import IKeyProvider

# Optionally pass a key provider so plugins receive a shared source for
# retrieving signing material.
key_provider: IKeyProvider | None = None
signer = MediaSigner(key_provider=key_provider)


async def sign_payload(payload: bytes) -> None:
    signatures = await signer.sign_bytes("jws", key="my-key", payload=payload)
    assert signatures, "At least one signature should be returned"
    print(signer.supports("jws"))


asyncio.run(sign_payload(b"payload"))

Integrating a key provider

Any Swarmauri key provider can be shared with the facade so backends receive ready-to-use key material:

import asyncio

from MediaSigner import MediaSigner
from swarmauri_keyprovider_inmemory import InMemoryKeyProvider

provider = InMemoryKeyProvider(keys={"local://demo": b"secret"})
signer = MediaSigner(key_provider=provider)


async def main() -> None:
    signatures = await signer.sign_bytes(
        "jws",
        key="local://demo",
        payload=b"demo",
        alg="HS256",
        opts={"kid": "demo"},
    )
    print(signatures[0].mode)


asyncio.run(main())

Discover installed plugins

Use the facade to list installed signers and inspect their capabilities:

for format_name in signer.supported_formats():
    capabilities = signer.supports(format_name)
    print(format_name, list(capabilities))

Why this structure?

• Separation of concerns – standards remain focused on common abstractions while the plugin encapsulates optional dependencies.
• Explicit opt-in – downstream projects can install only the signing stacks they need via the curated extras.
• Consistent ergonomics – usage matches the historical swarmauri_standard.signing.Signer import, preserving existing tutorials and code samples.

Command line utility

MediaSigner ships a small CLI for quick inspection and automation:

media-signer list                 # List available formats
media-signer supports jws         # Show capability metadata
media-signer sign-bytes jws \
  --alg HS256 \
  --key key.json \
  --input payload.bin \
  --output signatures.json

media-signer verify-bytes jws \
  --input payload.bin \
  --sigs signatures.json \
  --opts verify-keys.json

The CLI expects JSON files describing KeyRef objects and verification materials matching the selected plugin.

Project Resources

• Source: https://github.com/swarmauri/swarmauri-sdk/tree/main/pkgs/plugins/media_signer
• Documentation: https://github.com/swarmauri/swarmauri-sdk/tree/main/pkgs/plugins/media_signer#readme
• Issues: https://github.com/swarmauri/swarmauri-sdk/issues
• Releases: https://github.com/swarmauri/swarmauri-sdk/releases
• Discussions: https://github.com/orgs/swarmauri/discussions