PKIjärjestelmä

PKIjärjestelmä, often translated as Public Key Infrastructure, is a framework of hardware, software, policies, and procedures required to create, manage, distribute, use, store, and revoke digital certificates and manage public-key encryption. The primary purpose of a PKI is to enable secure electronic transfer of information for activities like e-commerce, internet banking, and confidential email. It establishes trust by binding public keys with their corresponding identities through a trusted third party, known as a Certificate Authority (CA).

A typical PKI involves several key components. The Certificate Authority (CA) is the entity responsible for issuing digital certificates. A Registration Authority (RA) may be used to verify the identity of users before a CA issues a certificate. The digital certificate itself contains the public key, identity information, and the CA's digital signature. A Certificate Revocation List (CRL) is a list of revoked digital certificates, and it is periodically published by the CA. Online Certificate Status Protocol (OCSP) is another method for checking the status of a digital certificate in real-time.

The core function of a PKI is to facilitate secure communication and transactions. It enables authentication, ensuring that parties involved are who they claim to be. It also provides non-repudiation, meaning that a sender cannot deny having sent a message. Confidentiality is achieved through encryption using public keys, and integrity is maintained by ensuring that data has not been tampered with. PKI systems are crucial for securing online activities and are fundamental to the operation of the internet and modern digital security.