In industrial and academic working environments, illegitimate academic certificates have been prepared by individuals who aim to be employed without completing regulated training and education programs. This violation has made an unjust confusion between genuine and fake certificates. Within the hiring process, employers thus need a reliable mechanism for verifying academic certificates that ensures the integrity of data. In accordance with this aim, blockchain technology has been introduced and deployed at some universities supporting fraud prevention or secure access to certificates. However, the method of handling knowledge in these educational systems was not investigated devotedly. This paper introduces an authentication framework of educational certificates that employed blockchain and ontology technologies, named BOCA. The learning ontology (LeOn), which was used to represent the central knowledge model of the system, was assigned to semantically manage the domain knowledge and link the educational data to the blockchain network. The system features, including the working process, the LeON ontological development, and the rule base construction, are described in detail. The system deployment on Hyperledger Fabric yielded promising experimental results. Ongoing work focuses on improving system performance and allowing semantic search on data blocks.