What is Public Key Infrastructure (PKI)?

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What is Public Key Infrastructure (PKI)?

The Public key infrastructure (PKI) is the set of hardware, software, policies, processes, and procedures required to create, manage, distribute, use, store, and revoke digital certificates and public-keys. The PKI is the foundation that enables the use of technologies, such as digital signatures and encryption, across large user populations. PKIs deliver the elements essential for a secure and trusted business environment for e-commerce and the growing Internet of Things (IoT).

PKIs help establish the identity of people, devices, and services – enabling controlled access to systems and resources, protection of data, and accountability in transactions. Next generation business applications are becoming more reliant on public key infrastructure (PKI) technology to guarantee high assurance as evolving business models are becoming more dependent on electronic interaction requiring online authentication and compliance with stricter data security regulations.

The Role of Certificate Authorities (CAs)

In order to bind public keys with their associated user (owner of the private key), PKIs use digital certificates. Digital certificates are the credentials that facilitate the verification of identities between users in a transaction. Much as a passport certifies one’s identity as a citizen of a country, the digital certificate establishes the identity of users within the ecosystem. Because digital certificates are used to identify the users to whom encrypted data is sent, or to verify the identity of the signer of information, protecting the authenticity and integrity of the certificate is imperative to maintain the trustworthiness of the system.

Certificate authorities (CAs) issue the digital credentials used to certify the identity of users. CAs underpin the security of a PKI and the services they support, and therefore can be the focus of sophisticated targeted attacks. In order to mitigate the risk of attacks against CAs, physical and logical controls as well as hardening mechanisms, such as hardware security modules (HSMs) have become necessary to ensure the integrity of a PKI.

PKI Deployment

PKIs provide a framework that enables cryptographic data security technologies such as digital certificates and signatures to be effectively deployed on a mass scale. PKIs support identity management services within and across networks and underpin online authentication inherent in secure socket layer (SSL) and transport layer security (TLS) for protecting internet traffic, as well as document and transaction signing, application code signing, and time-stamping. PKIs support solutions for desktop login, citizen identification, mass transit, mobile banking, and are critically important for device credentialing in the IoT. Device credentialing is becoming increasingly important to impart identities to growing numbers of cloud-based and internet-connected devices that run the gamut from smart phones to medical equipment.

Cryptographic Security

Using the principles of asymmetric and symmetric cryptography, PKIs facilitate the establishment of a secure exchange of data between users and devices – ensuring authenticity, confidentiality, and integrity of transactions. Users (also known as “Subscribers” in PKI parlance) can be individual end users, web servers, embedded systems, connected devices, or programs/applications that are executing business processes. Asymmetric cryptography provides the users, devices or services within an ecosystem with a key pair composed of a public and a private key component. A public key is available to anyone in the group for encryption or for verification of a digital signature. The private key on the other hand, must be kept secret and is only used by the entity to which it belongs, typically for tasks such as decryption or for the creation of digital signatures.

The Increasing Importance of PKIs

With evolving business models becoming more dependent on electronic transactions and digital documents, and with more Internet-aware devices connected to corporate networks, the role of a public key infrastructure is no longer limited to isolated systems such as secure email, smart cards for physical access or encrypted web traffic. PKIs today are expected to support larger numbers of applications, users and devices across complex ecosystems. And with stricter government and industry data security regulations, mainstream operating systems and business applications are becoming more reliant than ever on an organizational PKI to guarantee trust.