Public Key Infrastructure

Public Key Infrastructure (PKI) is the framework of policies, procedures, hardware, software, and roles needed to create, manage, distribute, use, store, and revoke digital certificates. PKI is what makes HTTPS, email encryption, code signing, and countless other secure communications trustworthy at scale.

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The Trust Problem

Asymmetric cryptography gives us public and private keys — but how do you know that a public key truly belongs to the person or organisation claiming it?

Without PKI:

• An attacker could publish a fake public key claiming to be your bank
• You would encrypt your credentials with the attacker's key, thinking it was the bank's
• This is the man-in-the-middle problem

PKI solves this by binding public keys to verified identities through digital certificates issued by trusted third parties.

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Core Components of PKI