The Blockcerts standard provides extension to the Open Badges standard to store the verification information of the certificate using blockchain technologies to enforce the integrity and allow a distributed timestamping of the issued certificates.
The data model is the same as the Open Badges one, adding the required data so that certificates validation can be stored in a blockchain.
Details about the data model extensions are provided in the following document:
The only entity extended by Blockcerts which has no relation at all with
storing and validating the certificates using blockchain technologies is
SignatureLine allows to place a handwritten
signature picture in a certificate to improve its visualization.
In order to enforce the security of the certificate upon validating it, Blockcerts uses blockchain technologies as a way to store information to validate the certificate, including in it a hash and a digital signature.
Check this document for more information about the verification process: