Encryption Protocols & Digital Certificates

Encryption Protocols

Purpose

• Allow for more security when communicating over the internet as it allows two parties identify and verify each other and communicate confidentially with integrity

• Provides encryption.

Working

• An SSL/TLS connection is initiated between two applications.

• The one initiating it is the client. The one receiving it is the server.

• Session begins with a handshake.

• Server sends its digital certificate and public key

• Client confirms the server’s identity.

• Encryption algorithm is agreed upon and the symmetric session keys are generated.

Use Cases

• Transmitting passwords or session cookies.

• Online shopping and banking websites.

Digital Certification

Digital Certificate

1. An organization sends a request to Certificate Authority (CA).

2. They send their public key, information to prove their identity as well as any additional information required by the CA.

3. The CA then verifies their identity and then issues the certificate after encrypting it with their private key.

Digital Signature

The message is put through a hashing algorithm to produce the digest. This is then encrypted with the sender’s private key. This is the digital signature.

When received the message and the digital signature are decrypted with the receiver’s private key. The digital signature is then decrypted with the sender’s public key. The decrypted message is put through the same hashing function to output a digest. The two digests are compared and if they are the same then the message was not tampered with.