Government agencies should use blockchain technology to securely verify and distribute sensitive documents such as vaccination certificates, rather than have citizens email such documents to their workplace, a security expert says.

A distributed blockchain ledger of encrypted documents, owned by a consortium of government agencies but accessible to employers, would provide citizens with greater control over the fate of their sensitive documents. It would also provide workplaces with machine-readable data that was far more efficient to process than current systems, said David Palmer, chief digital privacy officer at the data security company TrustGrid.