Public Key Infrastructure (PKI)
A PKI is a set of system, software, communication, and cryptography protocols required to use, manage, and control public key cryptography.
6 slides · 1 min read · Domain 3
It has four primary purposes
- Publish public keys/certificates
- Certify that a key is tied to an individual or entity
- Provide verification of the validity of a public key
- Provide security services such as confidentiality, integrity,authenticity, non-repudiation and access control
Ideally, we would be able to distribute PKIs and be assured that anyreceived PKIs were of the entity we are expecting to interact with.
Public keys mostly address, guarantee, and manage identity trust, specifically using digital certificates. This means that PKIs:
- Provide all the components necessary for users to communicate securely in a managed method
- Include hardware, software, policies, services, algorithms and protocols
- Enable C, and I of the CIA triad
- Enable non-repudiation
Text on this slide
Client
Random #
Hello
Public
Shared Secret (Session Key)
Server
Let's look at how PKI uses both asymmetric and symmetric encryption in the process.
1. Sends a "hello" message.
2. Server sends a copy of its asymmetric public key.
3. Client (browser) creates a symmetric session key (shared secret)and encrypts it with the server's asymmetric public key.
4. Server decrypts the asymmetric public key with its asymmetric private key to get the symmetric session key (shared secret).
5. Server and client (browser) now encrypt and decrypt all transmitted data with the symmetric session key (shared secret). This allows for secure communication between the client (browser) and server for that session. If the same client(browser) and server tried to connect on another day, a new session key would be created.