Modern Encryption Fundamentals

Mastering cryptographic techniques to protect digital communications

What is Encryption?

Encryption transforms plaintext into ciphertext using mathematical algorithms to protect data confidentiality. This guide explains core principles including symmetric/asymmetric systems, encryption modes, and practical implementation strategies.

AES-256-GCM
Gold standard for secure file encryption
RSA-4096
Asymmetric foundation for secure key exchange

Symmetric Encryption

Single-key systems like AES where both parties share the same secret key. Ideal for bulk data encryption but requires secure key exchange.

AES (Advanced Encryption Standard)

  • • 128/192/256-bit key sizes
  • • NIST standardized since 2001
  • • Used in TLS, FileVault, BitLocker

3DES (Triple DES)

  • • 168-bit effective key
  • • Considered deprecated for new systems
  • • Still used in some legacy banking systems

Asymmetric Encryption

Public/private key cryptography enables secure communication without pre-shared secrets. Used extensively for key exchange and digital signatures.

RSA Algorithm

Operates on large prime number factorization:

N = p × q
e × d ≡ 1 mod φ(N)

Encryption Modes

Determines how plaintext blocks are processed and combined with cryptographic keys. Each mode has unique security characteristics.

ECB (Electronic Codebook)

Splits data into blocks and encrypts identical blocks identically. Not recommended for most real-world applications.

CBC (Cipher Block Chaining)

E(XOR(P, IV)) or E(XOR(P, Cprev))
Requires proper initialization vector management to prevent vulnerabilities like padding oracle attacks

GCM (Galois/Counter Mode)

Provides both confidentiality and authentication in a single pass
Used in TLS 1.3 and modern secure communication protocols

Secure Key Management

Proper key lifecycle management is critical to maintaining encryption security across all systems.

Key Generation

  • • Use hardware security modules (HSMs) for cryptographic operations
  • • Derive keys using PBKDF2, BCrypt, or Argon2

Storage

  • • Never store plaintext cryptographic keys
  • • Use key wrapping with KMS (Key Management System)

Rotation

  • • Schedule regular key rotation
  • • Maintain key versioning for backward compatibility

Implementation Best Practices

Cryptographic Libraries

  • • Use well-audited libraries like OpenSSL or Libsodium
  • • Avoid rolling custom encryption implementations
  • • Stay updated with cryptographic advisory boards

Modern Solutions

Post-quantum algorithms: NIST SP 800-223

Zero-knowledge proofs for privacy-preserving systems