By RecOsint | Dec 6, 2025
How do we share secrets? Imagine you want to send a secret letter to a friend across the world. If you put it in a box and lock it, your friend needs the key to open it. But how do you send them the key without a thief stealing it on the way?This is the fundamental problem of cryptography.
This is the "Old School" method. – Concept: One Single Key is used to both Lock (Encrypt) and Unlock (Decrypt) the data. – Metaphor: It’s like your House Key. You use the same key to lock the door when you leave and open it when you return.
The "Key Exchange" Problem Symmetric encryption is incredibly fast. But it has a major flaw: You have to share the key.If you email the password/key to your friend and a hacker intercepts that email, they can unlock everything. – Verdict: Great for storage, risky for sharing.
To solve the sharing problem, we use Two Different Keys: 1. Public Key: Used ONLY to Lock (Encrypt). 2. Private Key: Used ONLY to Unlock (Decrypt). These keys are mathematically linked pairs.
Think of a Mailbox. 📬 – Public Key: This is the slot on the mailbox. Anyone (the public) can drop a letter in. – Private Key: This is the unique key that opens the box. Only You have it. – Result: Strangers can send you secrets securely without ever needing your private key.
So why not always use Asymmetric? Because it is Slow. – Symmetric (AES): Like a Ferrari. Very fast, efficient for large files (Hard Drives, Zip files). – Asymmetric (RSA): Like a Dump Truck. Very secure, but heavy computational load. Too slow for streaming Netflix.
How the Internet Works (HTTPS) When you visit a bank website, we use Both. 1. Handshake: The browser uses Asymmetric Encryption to safely exchange a "Session Key." 2. Data Transfer: Once the key is safely shared, the browser switches to Symmetric Encryption for speed. This is how SSL/TLS works.
Neither. You need both. – Symmetric: For speed and your own files. – Asymmetric: For sharing data over the internet safely.