Cert-Web-Component - Error when missing one parameter from cert-tools


I’m writing this topic, because it maybe be useful for someone that catch the same error that I did.

After issue my certificate, I achieve to view and to verify it in the blockcerts universal verifier website. Very well, the certificate was fine, and it has been passed in all tests.

So, I decided to setup the cert-web-component in my application to see the certificate. I was sure that It was without error, because it was validated in the Universal Verifier.

But, to my surprise, I got one error from Cert-Web-Component.

# Referenced certificate doesn’t appear to be valid

So, after some hours testing and matching with others Json certificates, I discovered the problem.

The field [–issuer_signature_lines ISSUER_SIGNATURE_LINES] was missing in cert-tools config.ini file (the certificate model).

Without this parameter the cert-web-component can’t render the certificate.

I think it should work because according with the documentation (https://github.com/blockchain-certificates/cert-tools) it’s a optional parameter, and as I said in the begin of the thread, it’s working, when uploaded to universal viewer, even missing the issuer_signature_lines field…


Hi @Fernando, if you have a github account, it may be good to file this as an issue on the cert-web-component repo. I’m not sure if it really is supposed to be required or not at this time.


I haven’t…

I’ll create one to register the issue there…


Hi @Fernando, you could achieve displaying certificates on your webpage using: https://github.com/blockchain-certificates/blockcerts-verifier

It is an update from the cert-web-component, as it handles natively both display and verification. The API allows you flexibility in the behavior and I think you could get where you want.


The blockcerts-verifier works with ethereum rospnet and bitcoin testnet ? I tried to use cert-web-component with ethereum without success…

Hi @Fernando, the blockcerts-verifier is agnostic of the chain. The only thing is that with a test chain, the verification process should appear gray and the validation message is different.

We have several test chains that we verify with blockcerts-verifier.

What is exactly the issue you are encountering? Could you provide a link/screenshot? Do you have errors in the console?


Hello @lemoustachiste

Thanks for answering,

I still didn’t tried cert-verifier… I just tried cert-web-component with bitcoin (working) and now trying it to ethereum (not working…)…

When I click to validade button… the console print:

Computing local hash…
validate-certificate.html:86 Comparing local and remote hashes…
validate-certificate.html:86 Checking the receipt…

and stop the JavaScript Program…

Could you share the certificate you are trying to validate? I can’t really help if I don’t see what’s happening




Verification happened successfully using blockcerts-verifier on blockcerts.org
cert-web-component has not been maintained and has been replaced by blockcerts-verifier. I encourage you to use it for displaying and verifying your certificates.

Hello @lemoustachiste

I took your suggest… and changed my project to blockcerts-verifier.

It’s a pretty better than web-component, and work to ethereum and bitcoin.

But, I realize some points:

a) Maybe it doesn’t work to check revocation list (Ethereum). I tried revocate the certificate upload here… but it still apear valid in verify button (https://certedu.eastus.cloudapp.azure.com/rev_UFP_2.json).

b) I’m not sure if it will allow to change the src programmatically, using for example JQuery.

I tried to change src with JQuery (the same way I did with web-component) but it doesnt work.. I created a Id and find it to change. I dont know if it allow do this, the same way web-component.

I`ll keep trying it.


Revocation on Ethereum works, if you try verifying this certificate you will get the verification error on the revocation: https://raw.githubusercontent.com/blockchain-certificates/cert-verifier-js/master/test/fixtures/ethereum-revoked-2.0.json

As to your second point I was not sure it was working, so I tried locally and it didn’t. But I figured it would be an easy change to make for this to work, so I went ahead and made it. It’s in PR now: https://github.com/blockchain-certificates/blockcerts-verifier/pull/94, but once merged (during the day), the next release should allow you to do it.

@Fernando v.1.14.0 is out and handles your need.

Cool ! Amazing component !

The src feature work very well, and I found the error in my revocate file.

Everything is working now with Cert-Verifier.

Thank you very much @lemoustachiste

Great, nice to hear it worked perfectly well for you.

If you have the time, do you think you could add some pt translations here: https://github.com/blockchain-certificates/cert-verifier-js/blob/master/src/data/i18n.json? It’s for the verification process. We want to internationalize the component even more (all internal strings) but haven’t had the time just yet, but this would be a good start already :slight_smile:

Ok, I’ll take a time to translate it to pt-Br.