What characterises the holder in SSI, and what is a wallet?

The holder is the person or entity that stores its credentials in a decentralised location it controls, the wallet, and decides which of them to pass on to which verifier.

The wallet is usually an app on the holder's smartphone. It does three things:

• Stores the credentials locally, not on an issuer's server.
• Protects the cryptographic keys that bind the credentials to the holder or device.
• Presents: when a verifier asks for proof, the wallet builds a presentation, shows the holder what is requested and sends it only with their consent.

Control is the point: the holder decides whether to present at all, to whom, and ideally how little to reveal (data-minimal presentation). This is the SSI principles of control and consent turned into software.

Go deeper:

• e-ID: Technologie (eid.admin.ch) — how the Swiss wallet, holder, issuers and verifiers fit together (in German).