Plenty of documents need more than one signature: a contract between two companies, a board resolution requiring several directors, a partnership agreement, a settlement both sides need to sign off on. The question these documents raise isn't just "did everyone agree," it's whether each individual signature can be checked on its own, independent of the others.
Why bundling signatures into one approval falls short
Some tools treat multi-party sign-off as a single event: everyone clicks approve, and the system records one completion status. That's fine for tracking whether a process finished, but it collapses a meaningful distinction if a dispute later focuses on one specific signer. If a document is contested and the question is whether one particular party actually signed, and when, a single bundled "completed" status doesn't answer that on its own.
How independent verification works instead
Each signer's signature is its own qualified electronic signature, under eIDAS and, for the same legal standing as a handwritten signature under Swiss law, OR Article 14 paragraph 2bis. Each is bound to that signer's own verified identity and its own qualified timestamp. If a document has three signers, there are three independently verifiable signatures on the record, each checkable without needing to also validate the other two.
This matters practically. A board resolution might later be questioned by one director specifically, not the whole board. A two-party contract might have one side dispute their own signature while the other side's isn't in question at all. Independent verification means the document can answer a question about any one signer without the answer depending on the others.
What this looks like for the underlying file
The document itself is still a single sealed file, hashed once, so any change to its content after signing is detectable the same way it would be for a single-signer document. What multi-signature adds is that the identity and signature layer sits per-signer, not per-document. The file's integrity is one check. Each person's signature is a separate, independently checkable fact.
