You can verify documents that have been issued by Singapore government entities with a .oa file on verify.gov.sg.

GovTech Singapore developed verify.gov.sg backed by blockchain technology.

For educational and training certificates, please visit https://www.opencerts.io instead.

Using blockchain, we can greatly reduce the barrier of entry to publishing protected documents in a secure format, instead of using existing proprietary software that is costly. In addition, a public blockchain is owned and maintained by the community and is easily accessible by anyone. As a result, there is no need to run or maintain services to verify documents.

Printing the verified document discards all the advanced protections we have built to preserve the .oa file in a secure format. Printed documents cannot be verified.

You can verify your .oa file by either (i) uploading it or (ii) scanning the QR code with your mobile device camera or a barcode scanner.

A verified document that has been modified will show up as having been tampered with.

Document contents and personal data are not published on the blockchain. A hash (a unique digital code) is generated from the document and is used to prove that the document is legitimate. Since the hash is the only information published into the blockchain, no personal information can be obtained from content on the blockchain.

In every properly issued .oa file, there is a hash which is a unique digital code to verify that the contents of the document have not been altered.

The Ethereum Blockchain is a publicly usable distributed ledger based on blockchain technology. You can think of it as a publicly readable database. Ethereum is the blockchain network with the largest developer base, as well as having a large number of participants securing the network.

It means that the issuer has officially cancelled the document such that the document is no longer valid.