What is an RSA Key Used For?

If you have ever generated a CSR or installed an SSL certificate, you have likely seen the term RSA (which stands for Rivest-Shamir-Adleman, the inventors of the algorithm). But what exactly is this key, and why is it so important for your websites security?

In short, an RSA key is the foundation of Asymmetric Encryption. It allows two parties (your website and your visitor) to communicate securely without ever having met before.

The Concept: Two Keys are Better Than One

Unlike a physical house key where the same key locks and unlocks the door, RSA uses a "Key Pair" system:

1. The Public Key: This is embedded in your SSL certificate. It is shared with the entire world. Anyone can use this key to encrypt (lock) data.

2. The Private Key: This stays secret on your Nixzoehost server. It is the only key in existence that can decrypt (unlock) the data encrypted by your Public Key.

How RSA Works in a Website Visit

When a customer visits your site, a "handshake" happens in milliseconds:

• The Lock: Your server sends the Public Key (via the SSL) to the customers browser. The browser uses this key to lock a small piece of secret data.

• The Travel: That locked data is sent across the internet. Even if a hacker intercepts it, they cannot read it because they don't have the Private Key.

• The Unlock: Your Nixzoehost server receives the data and uses its Private Key to unlock it. Now, both the browser and the server have a shared secret to talk privately.

Why 2048-bit?

When you generate a CSR in cPanel, you will see an option for "Key Size." At Nixzoehost, we use 2048-bit as the standard.

• The Math: This number refers to the length of the numbers used in the RSA algorithm.

• The Security: A 2048-bit key is so complex that even the worlds fastest supercomputers would take billions of years to crack it by "guessing" the Private Key.

Why Should You Care?

Understanding RSA keys helps you manage your SSL better:

• Key Safety: Since the Private Key is the only thing that can unlock your data, losing it means your SSL is broken.

• Encryption Strength: Using RSA 2048-bit ensures your site meets the security requirements of modern browsers like Chrome and Firefox, as well as PCI-DSS standards for taking credit card payments.

Summary: RSA Key Roles

Nixzoehost Security Fact: We constantly update our server hardware to ensure that RSA handshakes are processed instantly, so your high-level security never slows down your websites loading speed.