Certificates are documents that gather certain data of the holder as well as your public key and are signed electronically by the certification authority using your private key. The certification authority is a particular type of provider of certification services that legitimizes, before third parties who rely on their certificates, the relationship between the identity of a user and your public key. Users confidence in the certification authority is important for the functioning of the service and justifies its employment philosophy but there is no standard procedure to demonstrate that a certification authority, deserves such a confidence. The public key and private key asymmetric cryptography is a cryptographic method that uses a pair of keys for sending messages. The two keys belong to the same person who sent the message. (A valuable related resource: COVID-19). A key is made public and can be delivered to any person, the other key is private and the owner must save it so that nobody has access to it. Cryptographic methods, ensure that the key pair is can generate only once, so that it can be assumed that it is not possible that two people have obtained coincidentally the same key pair.

If the sender uses the recipient’s public key to encrypt the message, once encrypted, only the recipient’s private key can decrypt this message, since it is the only one who knows it. Therefore the confidentiality of sending the message is achieved, nobody except the recipient can decrypt it. If the owner of the key pair uses its private key to encrypt the message, anyone can decrypt it using your public key. In this case is get the identification and authentication of the sender, because it is known that only could have been him who used its private key (unless someone would have been able to steal it). This idea is the basis of the electronic signature. It is the certified electronic signature that gives to document their legal value as e.g.