Public Key Infrastructure (PKI): A framework that manages digital keys and certificates, and enables secure communication.
Public Key Infrastructure (PKI) is a comprehensive system designed to secure communications, identities, and data. It employs asymmetric cryptography, also known as public-key cryptography, to secure the confidentially, integrity, and authenticity of data in transit and at rest. PKI is fundamental to technologies such as SSL/TLS, secure email, and digitally signed documents.
Components of PKI:
- Digital Certificate: An electronic “passport” that establishes your credentials when doing business or other transactions on the web.
- Certificate Authority (CA): A trusted entity that issues digital certificates. The CA verifies the identity of the certificate holder and provides them with a certificate.
- Registration Authority (RA): An authority in a PKI that verifies user requests for a digital certificate and tells the certificate authority (CA) to issue it.
- Certificate Revocation List (CRL): A list of certificates that have been revoked by the CA before their expiration date.
- Public and Private Keys: The cornerstone of PKI is the cryptographic key pair, consisting of a public key and a private key.
- Key Generation: Public and private keys are generated as a pair and are mathematically linked.
- Certificate Issuance: After verification, the CA will issue a digital certificate to the requester.
- Certificate Storage: Certificates and private keys can be stored in secure locations like hardware security modules (HSMs), smart cards, or in software-based cryptographic stores.
- Certificate Validation: When a secure connection is required, certificates are mutually authenticated and validated either manually by the user or automatically by the system.
- Certificate Renewal and Revocation: Certificates have a finite lifespan and need to be renewed. They can also be revoked if compromised.
- Strong Security: PKI is highly scalable and can offer strong security measures suitable for high-stakes applications.
- Trust: Once a CA is established as trustworthy, all certificates issued by it inherit that trust.
- Data Integrity: PKI ensures that data is not tampered with during transit.
- Non-repudiation: PKI provides strong evidence that a particular user took a specific action, like sending an email or signing a document, thus preventing denial of those actions later on.
- Complexity: Managing a PKI system can be complex and requires specialized knowledge.
- Cost: Depending on the solution, the costs can be high for certificate issuance and management.
- Timely Revocation: Revoking compromised certificates in a timely manner can be challenging.