Skip to content

Latest commit

 

History

History
81 lines (56 loc) · 2.33 KB

Module4.md

File metadata and controls

81 lines (56 loc) · 2.33 KB
Raw

Module 4: Cryptography

4.1 Cryptographic Fundamentals

Encryption and Decryption

Cryptography is the cornerstone of secure communication. Encryption ensures that information remains confidential during transmission and storage.

Symmetric Encryption:

  • Utilizes a single key for both encryption and decryption.
  • Example: Using the openssl command for symmetric encryption with AES:
openssl enc -aes-256-cbc -in plaintext.txt -out ciphertext.enc

Asymmetric Encryption:

  • Involves a pair of public and private keys for encryption and decryption.
  • Example: Generating an RSA key pair with openssl :
openssl genpkey -algorithm RSA -out private_key.pem
openssl rsa -pubout -in private_key.pem -out public_key.pem

#Hash Functions and Digital Signatures

Hash functions create fixed-size outputs (hashes) from variable-size inputs. Digital signatures use asymmetric cryptography to verify the authenticity and integrity of messages.

Hash Functions:

  • Example: Computing an SHA-256 hash with openssl :
openssl dgst -sha256 file.txt

Digital Signatures:

  • Example: Generating a digital signature with openssl :
openssl dgst -sha256 -sign private_key.pem -out signature.sig file.txt

4.2 Public Key Infrastructure (PKI)

Certificate Authorities (CAs)

Public Key Infrastructure (PKI) relies on Certificate Authorities (CAs) to issue and manage digital certificates.

Issuing Certificates:

  1. Certificate Signing Request (CSR): Generate a CSR with openssl :

    openssl req -newkey rsa:2048 -keyout private_key.pem -out csr.pem

  2. CA Signing: A CA signs the CSR, producing a digital certificate.

SSL/TLS Protocols

Secure Sockets Layer (SSL) and its successor, Transport Layer Security (TLS), provide secure communication over the internet.

Configuring SSL/TLS:

  • Example: Configuring an Nginx server with SSL:
server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /path/to/certificate.crt;
    ssl_certificate_key /path/to/private_key.key;

    # Additional SSL configurations...
}

Go to Index | Previous Module: Operating System Security | Next Module: Web Application Security

Secure the Future. Learn Cybersecurity.

-Ritwik Dadarwal ;)