🔐 Secure vs Non-Secure RNG — Understanding the Difference

Random Number Generators (RNGs) are everywhere — from games to security systems. They fall into two categories: non-secure (general-purpose) and secure (cryptographic). Choosing the right type ensures fairness, unpredictability, and safety.

Non-Secure RNGs (General-Purpose)

• Common uses: Games, UI animations, casual simulations, and educational tools.
• Speed: Extremely fast and lightweight.
• Predictability: Can be predicted if internal state is known; not safe for security-critical applications.

Secure RNGs (Cryptographic)

• Common uses: Passwords, session tokens, lotteries, encryption keys, and any scenario needing strong unpredictability.
• Strength: Designed to be unpredictable, even if an attacker observes outputs.
• Performance: Slightly slower than non-secure RNGs but fast enough for most applications.

When to Use Each

• Non-secure RNG: For casual applications where fairness is desired but security is not critical — e.g., dice rolls, random quotes, UI effects.
• Secure RNG: For security-sensitive operations where unpredictability matters — e.g., password generation, secure tokens, cryptographic keys, official draws.

Practical Examples

• Non-secure: Math.random() in JavaScript for rolling a virtual dice.
• Secure: window.crypto.getRandomValues() for generating secure tokens or encryption keys.
• Server-side secure RNGs: Use System.Security.Cryptography.RandomNumberGenerator in .NET or secrets module in Python.