When two hosts want to transfer sensitive data between them, they use encrypted communication. Both the hosts first connect to each other and authenticate themselves. After that, an encrypted connection is established, using which sensitive data are transferred.

If a host wants to authenticate itself to the other host, it must prove its identity. Usually, public-key cryptography is used for that purpose. Each host possesses a private-public key pair. And, to establish an encrypted connection, they share their public keys with each other.

But, one has to confirm that the shared public key indeed belongs to the sender. Public Key Infrastructure, or PKI, is an arrangement that is used for that purpose. It binds public keys with corresponding identities through registration and issuance of certificates and using a centralized authority called Certificate Authority or CA. PKI consists of a set of roles, policies, and procedures to create, manage, distribute, or revoke digital certificates.

What is Public Key Infrastructure or PKI?

PKI consists of the following components :

• Certificate Authority
• Registration Authority
• Central Directory
• Certificate Management System
• Certificate Policy

Certificate Authority

A Certificate Authority issues a digital certificate to an entity. The issued digital certificate is signed with the CA’s private key so that it is not tampered with. When a host gets a digital certificate from another host, it checks with the corresponding CA to make sure it is authentic.

Registration Authority

When an entity requests a digital certificate, the Registration Authority verifies the identity of the entity to make sure the digital certificate is not mis-issued.

Central Directory

A Central Directory is a central location where public keys are stored and indexed so that they can be retrieved at the time of verification of digital certificates.

Certificate Management System

A Certificate Management System manages access to stored certificates and the delivery of the certificates to be issued.

Certificate Policy

It consists of policies of digital certificates.

What is Decentralized Public Key Infrastructure?

Relying on a centralized authority in a PKI has several disadvantages. A digital certificate can be mis-issued by a CA for a number of reasons, and when that happens, security is heavily compromised.

To address the disadvantages of using a centralized authority, a Decentralized Public Key …