ASiC: Associated Signature Containers

A standardized container associating digital files with the detached signatures or time assertions that apply to them.

Published on

2026-11-06

Last updated on

ASiC keeps files and their associated signature or time-assertion material together.
ASiC-S and ASiC-E define different container structures.
Extracting one document does not necessarily preserve the whole validation package.

What is an Associated Signature Container?

An Associated Signature Container (ASiC) is a standardized digital package linking data files with associated signatures or time assertions. It uses a ZIP-based structure defined by ETSI EN 319 162-1; merely renaming an ordinary ZIP file does not make it a conforming ASiC container.

ASiC-S versus ASiC-E

ASiC-S, or simple: associates one data file with the relevant signature or time-assertion material. That data file can itself be an archive containing several objects.
ASiC-E, or extended: supports multiple data objects and associated signatures or time assertions under the applicable profile.

The distinction concerns container structure, not a universal difference in legal strength. A filename or extension alone does not establish that the contents conform or that every file has been signed.

What does the package preserve?

The container keeps payloads and their signature relationships together. It can use CAdES or XAdES signature structures and relevant time assertions. The exact objects covered must still be checked; packaging does not automatically prove identity, authority or qualified-signature status.

Extracting a document can make it readable, but that individual file is not necessarily the complete evidence package. Preserve the container, referenced objects and supporting material needed for validation.

Container versus long-term preservation

An ASiC package can carry material supporting later signature validation. Keeping a ZIP-based file is not, by itself, a guarantee of long-term verifiability. Validation still depends on its signatures, trust information, time evidence and applicable preservation process.

A Common Case: Receiving an EU partner’s signed package

Consider a Washington consulting firm receiving an ASiC package from an EU partner. Keeping the complete container allows the team to review the covered files and associated evidence. Extracting a readable agreement alone may leave that review incomplete.