The property that someone who signed or sent something cannot later credibly deny it.
A digital signature shows that a key signed a document. Non-repudiation needs more: that the key belonged to one person, that only they could use it, and that they saw what they signed.
Attestation supplies the missing pieces. A key attestation shows the key was created in certified hardware and cannot be copied. Attestation of the signing service shows which software asked the key to sign. A log that cannot be rewritten shows when.
This is why qualified electronic signatures require certified signature devices. It is also why a remote signing service has to prove that a key in a data centre is under the sole control of its owner. Each of those proofs describes a system that gets updated, so each has to be renewed.
Attested wallets and digital identityContinuous compliance
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Next fixed date: EU Digital Identity Wallets are due in every member state on 24 December 2026, 42 days from now.