x.509 is an international digital certificate used for verification in different internet protocols. It can be applied to verify either a person or a website name, an email address, etc. Its main advantage is that it allows minimizing problems which might occur while encrypting and exchanging confidential information, like data interception or cracking. While using the certificate system, you may be quite sure you have encrypted your data in such a way that it can be read only by the intended recipient.
The system implies the use of public key encryption, which actually means you deal with two keys, from which one is made public and the other is kept private by the owner of the key. Typically, a message is encrypted using the public key.But it is only the owner of the private key who can decrypt it. Alternatively, a message is encrypted with the private key and decrypted with the public one, for example, when it goes about the signature which is created by the owner of the private key and then can be verified by any other person.
The complexity of the mathematical relationship between the public key and the private key secures private key from cracking.Moreover, there exist time limitations within which the certificate is active. And there can be other constraints on the use of the certificate.
The certificate contains a digital signature, the purpose of which is to certify the validity of the information in the certificate. The certificate cannot be trusted without verification of the signature. The signature is generated in such a way that it will not verify in case any important information in the certificate has been tampered with.
