2.4. Cryptographic Solutions

💡 First Principle: Without cryptography, every password would travel in plain text and every digital signature would be forgeable. Cryptography is the mathematical foundation that makes digital trust possible. Every secure connection, verified identity, protected secret, and provable signature relies on cryptographic algorithms. Without cryptography, confidentiality, integrity, and non-repudiation are impossible in digital systems.

What breaks without proper cryptography? Everything. Passwords stored in plaintext are stolen in bulk. Unencrypted network traffic is readable by anyone on the path. Unsigned software updates can be replaced with malware. Expired certificates crash services. Think of cryptography like a digital envelope — it operates even when every other control has failed. If an attacker reaches the database, encryption keeps data unreadable. If a message is intercepted, digital signatures prove tampering occurred.

The distinction between symmetric and asymmetric encryption isn't academic — it determines which algorithm you choose for each scenario. Symmetric is fast but requires a pre-shared key. Asymmetric solves key distribution but is too slow for bulk data. Real-world systems combine both, and the exam expects you to know why.