Zero-Knowledge Proof
A zero-knowledge proof is a cryptographic method for proving that a statement is true, such as "the holder is over 18", without revealing any of the underlying data the statement is based on, such as the actual birth date.
Where selective disclosure lets a holder reveal chosen claims as-is, a zero-knowledge proof reveals nothing at all: the verifier learns only that the statement holds, backed by a proof it can check against the issuer's signature. This is a stronger privacy guarantee than selective disclosure, and an active area of standardisation for future credential formats used in the EUDI Wallet ecosystem.