The Blockchain is, in simple terms, a database distributed in a multitude of computers that collaborate together in the Internet space.
An educational institution and a student agree to register any certification in the database, and sign and encrypt it using cryptographic techniques. Then, the student may address any other institution and share his certificate, whose veracity can be checked directly in the Blockchain without having to contact again with the Institution that issued it.
The Blockchain design means that there are many copies of the database on the Internet, all of them necessary and absolutely identical. This makes fraud impossible, and also guarantees the survival of the certificates issued by the educational institution, even in the event that the institution disappears. The certificates thus registered are perennial and immutable.