Foundations of Cryptography & Physical Security — Ethical Hacking 101
Cryptography: Shielding Information from Prying Eyes
At the heart of cybersecurity lies cryptography, the art of securing information through various techniques.
- Obfuscation: This involves transforming data into a seemingly unintelligible form. Examples include simple substitution ciphers like the Caesar Cipher and ROT2, where letters are shifted a fixed number of positions in the alphabet. While easy to implement, these methods are also vulnerable to cryptanalysis, the art of code-breaking.
- Diffusion and Confusion: More robust encryption methods employ diffusion and confusion to make it significantly harder to decipher the original message. This involves spreading out the influence of each plaintext bit over many ciphertext bits and obscuring the relationship between the key and the ciphertext.
- Modern Encryption: Modern cryptography relies on complex algorithms and long keys to ensure robust protection. Examples include the Advanced Encryption Standard (AES) and the Rivest–Shamir–Adleman (RSA) algorithm, which form the backbone of secure communication on the internet.
Hashing: Ensuring Integrity and Authenticity
Hashing algorithms play a crucial role in verifying the integrity of data. They convert any input data into a fixed-length string of characters, known as a hash or message digest. Even a minor change in the input data will result in a completely different hash, making it easy to detect tampering or corruption. Popular hashing algorithms include:
- MD5: An older algorithm, now considered insecure due to vulnerabilities like collisions, where two different inputs produce the same hash.
- SHA-1: Similar to MD5, also susceptible to collisions.
- SHA-2 Family: The current standard, including SHA-256 and SHA-512, offering significantly better security against collisions.
- RIPEMD: A less common but open-standard hashing algorithm with various versions offering different digest lengths.
Cryptanalysis: Breaking the Code
While cryptography aims to protect information, cryptanalysis seeks to break it. Attackers can target the algorithm itself, searching for weaknesses, or focus on the implementation, exploiting vulnerabilities in software or hardware. A common target is password cracking, where attackers use techniques like dictionary attacks or rainbow tables to guess passwords.
Defense Against Password Cracking:
- Salting: Adding a random string of characters to the password before hashing it, making rainbow tables ineffective.
- Key Stretching: Using algorithms like PBKDF2 to slow down the hashing process, making brute-force attacks computationally expensive.
Physical Security: Protecting the Tangible
Beyond the digital realm, physical security plays a vital role in safeguarding sensitive information and assets. This includes:
- Access Control: Implementing measures such as key cards, biometric authentication, and visitor logs to restrict access to critical areas.
- Surveillance: Utilizing security cameras, motion detectors, and security personnel to monitor and deter unauthorized access.
- Environmental Control: Maintaining optimal temperature, humidity, and airflow to protect equipment and prevent data loss.
- Device Security: Disabling unnecessary ports, changing default passwords, and firewalls to secure IoT devices and prevent unauthorized access.
