How to convert existing PDF certificates to blockcerts certificate?

It is good that Blockcerts has created this open source tool for creating blockchain certificates. Companies like learningmachine are partnering with universities to issue blockcerts verifiable certificates. Which is great. But this is only addressing the problem with new certificates.

What about the certificates that are issued already? There are trillions of certificates already issued which are either in PDF or image formats. Take my case. I completed my university studies decades ago and not planning to go back anytime soon. I have bunch of paper/PDF certificates with me. How can I convert this into blockchain certificate?

To solve my problem, I created a tool to convert any PDF of image certificates into blockcerts and found it useful. Then I created a nice user interface and started uploading all my important documents. I’ve deployed this at

The certificates created by me are not endorsed or verified by respective universities. But we are planning to add simple workflow to add verifications in future.

While playing and tinkering I also found other uses for blockcerts. Blockerts certificates not only addresses the problem of verification. It also solves the problem of storing and sharing certificates easily.

This solved another problem for me. All my important certificates and documents were scattered around multiple cloud storage services. Now I was able to organize all of them in one place.

Anyone can signup and drag/drop to create blockcerts certificate. The hash is anchored in Ethreum blockchain and passes all blockcerts validation. The PDF or image document is converted into base64 bytes and stored inside the json file. So json file can recreate the actual certificate without any external dependencies.

It is always better to see it in action to believe it. Go ahead, sign up at to drag & drop a document.

Any feedback both positive and negative is much appreciated.

Just checked out proofplum…it’s fantastic !!!

I think the correct answer to the question is that one would use an attestation to make a legacy document into a Verifiable Credential. Without looking too closely, it appears that the ProofPlum application is creating a certificate in BlockCerts format, but it is a self-issued cert. To make a proper VC, it must come from the original issuer as an attestation.

A similar problem exists in, for example, India government submissions. Govt of India will not accept scanned signatures in PDF documents unless the app that is doing the insertion includes an attestation from a Certificate Authority.

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Hi Mark, Thanks for your positive feedback.

Good point on Attestation. Self issued cert is the starting point to increase awareness. We are actively working on developing additional business process where the certificate issuing authority can attest the document which will be another blockchain transaction. This will increase the credibility and validity of the certificate.

Great tool! But why a json generated by proofplum isn’t valid in the blockcert universal verifier ?

Hi Viky, Thanks for checking it out and posting the issue. The generated cert is blockcerts compatible and should work on all blockerts universal verifier. What browser are you using? or could be an error in our system. Can you do this?

  1. Can you check to see if this JSON is working for you?

  2. When did you create your certificate? is it working with

You can also DM me with a screenshot and I can happy to look at.

again, thanks for checking it out.

  1. Sample works
  2. I’ve created a new certificate this morning and I get the following error: “Unable to get issuer profile” on the blockcert verifier :

Hi Viky, Thanks for checking again and providing additional info. I have seen that error before. It happens when the first time issuer profile is not loaded correctly. If you refresh couple of times, it should able to pull it up. I tested the same json on several browsers and worked correctly. It may also be pulled from cache. Also let me know the browser you are using.

Thx, it works also in the blockcerts mobile app and in a chrome private window! Certainly a bug in the blockcerts verifier.
Another question, why are several links needed ? to be verified in proofplum to “download record in a JSON format” is used to be verified in blockcert
… not very user friendly… Is there any way to get a single link that can access to certificate and be verifiable in blockcert ?

pretty kool app by the way

Hey Viky., Thanks for the feedback. Agree with you on making the links user friendly. When we started we wanted to show only one link. Which is For non technical user the JSON link is useless and may be we will remove it from FAQs. We created the PDF file so that it can be easily shared. Today everyone asks to upload your certificate in PDF format. So the user can share the PDF file which contains all information for someone to verify the certificate. At some point in future, everyone transitions to blockcerts and only asks for the verification link. Until then, we have to keep it multiple formats.

let me know if you have any specific suggestions to make it easy for end users.

Thanks again.

hi @akmedia
I’ve written to you a couple of times through the proofplum support because I can’t get it to work for me.
Could you look at it please? I am looking for a way to certify on blockchain and that students can use blockcerts and I think that if we get proofplum to work it could serve us very well.
I would appreciate it if you would look at my messages and reply to see if we can make it work for us.
Thank you

Hey Arun, I’m just seeing Proofplum now and I agree with mark_s…fantastic. Innovative and thoughtful use of the blockcerts initiative. There are so many existing documents that could be entered onto the blockchain-I guess the question then would be was their provenance actually established before that??!