Cryptographic hash functions are fundamental to security. Learn about MD5, SHA families, and when to use each.

What is a Hash?

A one-way function that converts any input into fixed-length output. Impossible to reverse.

Algorithm Comparison

• MD5 - Broken, avoid
• SHA-1 - Deprecated
• SHA-256 - Standard choice
• SHA-512 - High security

Use Cases

• Password storage (with salt)
• File integrity
• Digital signatures

Conclusion

Always use modern algorithms. SHA-256 or better for new applications.