Experts suggest government agencies use blockchain technology to secure vaccination certificates. 

David Palmer, chief digital privacy officer at data security company TrustGrid, says the government can use the technology to securely store and exchange credentials.

He suggests a distributed blockchain ledger of encrypted documents, owned by government agencies but accessible to employers, would provide greater control over what happens to their sensitive documents. 

Workplaces would also be provided with machine-readable data that is far more efficient to process than current systems. 

Mr Palmer has a commercial interest in his suggestions, as this is exactly what his company TrustGrid offers. 

He has been a vocal critic of the government vaccination certificates being distributed in PDF form, as these can be easily forged, and are hard for businesses to authenticate.

If vaccination details were stored on a blockchain, they could not be altered and would remain under the control of the individual.

Each entry on the blockchain ledger could be encrypted, unlocked only when the individual supplies a passphrase, or even biometric information.

Using this system, employees could pass on their verified data to the workplace without that workplace ever needing to store the credential itself.