How encryption works

Encryption is the process of converting readable information into a scrambled code that hides the information's true meaning. The purpose of encryption is to protect digital data confidentiality as it's stored on computer systems and transmitted using the internet or other computer networks.

The outdated data encryption standard (DES) algorithms defined in the late 1970s and used extensively in the 1980s and early 1990s are now easily crackable. Advanced Encryption Standard (AES), a more robust encryption standard, is now required by the U.S. government for protecting classified information and is widely used in software and hardware to encrypt sensitive data.

There are two main types of encryption:

Symmetric Encryption

In symmetric encryption, the same key is used for both encryption and decryption. This means that both the sender and receiver must have the same secret key. Examples include:

• AES (Advanced Encryption Standard) - Currently the most widely used symmetric encryption algorithm
• DES (Data Encryption Standard) - Legacy encryption that is now considered insecure
• 3DES (Triple DES) - An improvement over DES that applies the algorithm three times

The main advantage of symmetric encryption is speed - it's much faster than asymmetric encryption. However, the challenge is securely distributing the secret key to both parties.

Asymmetric Encryption (Public Key Cryptography)

Asymmetric encryption uses a pair of keys: a public key and a private key. The public key can be freely shared, while the private key must be kept secret. Data encrypted with the public key can only be decrypted with the corresponding private key, and vice versa.

Common asymmetric encryption algorithms include:

• RSA - Named after Rivest, Shamir, and Adleman, widely used for secure data transmission
• Elliptic Curve Cryptography (ECC) - Provides the same security as RSA with smaller key sizes
• Diffie-Hellman - Used for secure key exchange

While asymmetric encryption solves the key distribution problem, it's much slower than symmetric encryption, which is why many systems use a hybrid approach.

How Encryption Protects Data

Encryption provides several security benefits:

• Confidentiality - Ensures that only authorized parties can read the data
• Integrity - Helps detect if data has been tampered with
• Authentication - Verifies the identity of the sender
• Non-repudiation - Prevents the sender from denying they sent the message

In modern networking and cybersecurity, encryption is essential for protecting sensitive information as it travels across networks or is stored on systems. Understanding how encryption works is fundamental for anyone working with network security, whether you're studying for your CCNA or working as a network administrator.