Since the introduction of our blockchain notary, every document uploaded to our platform is certified and stamped on the Bitcoin blockchain.

Although the notary performs all steps of the verification automatically, this documents describes, how you can do all these steps on your own. For the verification, we need three files: the PDF, the certificate, and the timestamp. The certificate is generated by Ledgy and attests, that a document has been uploaded to our platform, by whom, and for which company. The then timestamp proves the existence of the certificate at a given time. Let’s get started!

Attestation details of a document that has been uploaded to Ledgy


First, check that your PDF is correct. SHA256 File Checksum Online allows you to select your local PDF document and compute its hash value. Check that this is equal to the one shown in the Attestation details.

Verifying the integrity of the document

The Certificate

Second, verify the signature of the certificate. Visit TweetNaCl.js and click Verify. From the Attestation details, copy the signature into the Signature field, and the JSON into the Message field. Finally, the Public Key for all messages is gs04X1XPvYqg0zlsXCcRj+ZvxeHjqOBg1Ac8PZB4UR0=

Now, press verify, and you will see the success message.

Certificate successfully verified!

The Timestamp

From the Attestation details, download both the certificate and the timestamp. Visit and select first, the certificate, and second, the timestamp.

That’s it. If everything worked fine, you have now proved, that the document is valid and was uploaded by Ledgy at the given time!

Yay, the document, certificate, and timestamp are valid!
24 Sep 2018Suggest changes
Timo Horstschaefer
Timo Horstschaefer
Co-Founder & CTO