Cryptography Attacks

Understanding the most common cryptographic vulnerabilities

Introduction

Cryptographic systems are mathematical constructs designed to secure data, but they can be exploited through various attack vectors. This guide explains five major attack types and their mitigation strategies.

1. Brute Force Attacks

Trying all possible key combinations until the correct one is found. This works best against weak encryption algorithms or small keyspaces.

Example: Cracking DES encryption (56-bit key) using supercomputers.
  • Use AES-256 or higher for encryption
  • Implement password complexity requirements
  • Enforce account lockouts after retries

2. Dictionary Attacks

Exploiting common password patterns by testing pre-compiled lists of likely candidates rather than random combinations.

Pattern: "Password123" appears in 10% of breaches.
  • Reject common password patterns
  • Enforce multi-factor authentication
  • Implement rate-limiting on login attempts

3. Man-in-the-Middle (MITM)

Intercepting communications between parties to steal encrypted data or inject malicious content.

Attack Surface: Unencrypted Wi-Fi hotspots
  • Use TLS 1.3 with PFS (Perfect Forward Secrecy)
  • Verify certificate fingerprints manually
  • Require domain validation for SSL certificates

4. Side-Channel Attacks

Measuring physical characteristics (power usage, electromagnetic emissions) to infer cryptographic keys.

Example: Power analysis compromising smartcards
  • Implement physical security measures
  • Use constant-time algorithms
  • Shield devices from emissions

5. Padding Oracle Attacks

Exploiting inconsistent encryption padding errors to decrypt ciphertext without knowing the key.

Vulnerable: CBC-mode encryption with unverified MACs
  • Use authenticated encryption (AES-GCM)
  • Verify MACs before decryption
  • Implement timing-attack resistant validation