使用JWS JSON序列化的多签名JWS有何应用场景？

Great question! The ability to attach multiple signatures to a single JWS via JSON serialization solves several practical problems where multiple parties need to validate, endorse, or audit a payload. Here are the key application scenarios:

• Multi-Party Approval Workflows
  Think of business processes like contract signing, purchase order approval, or document review. For example, a vendor contract might need signatures from your company's legal team, finance department, and the vendor itself. Each party signs the same payload with their own private key, and any stakeholder can verify that all required parties have endorsed the document—no need to generate separate JWS for each signature.

• Cross-Environment Trust Validation
  When a payload needs to be trusted across different security domains. Suppose you have an API payload that's used both internally (validated against your company's internal CA) and by external partners (validated against a shared industry CA). Adding signatures from both key pairs lets each system validate the JWS using their trusted key, eliminating the need to create duplicate JWS for each environment.

• Audit Trails and Non-Repudiation
  In regulated industries like finance or healthcare, you need irrefutable proof that a payload was reviewed or authorized by specific parties. For instance, a financial transaction might require a signature from the processing service and a compliance team to confirm it meets regulatory standards. Each signature acts as a timestamped audit entry, making it impossible for any party to deny their involvement later.

• Progressive Authorization Stages
  For content that moves through multiple approval tiers. A blog post, for example, might start with a draft signed by a writer, then get an editor's signature after review, and finally a publisher's signature when it's ready to go live. Systems can check which signatures exist to determine the content's current stage and enforce appropriate access or actions.

• Interoperability Across Diverse Systems
  When dealing with legacy and modern systems that use different signature algorithms or key types. If one system only supports RSA signatures and another uses ECDSA, you can sign the payload with both algorithms in a single JWS JSON serialization. Each system can validate the signature that matches its supported method, avoiding the overhead of converting payloads or maintaining separate JWS instances.

内容的提问来源于stack exchange，提问作者Rob L