An SSL certificate is a bit of code on your web server that provides security for online communications. When a web browser contacts your secured website, the SSL certificate enables an encrypted connection. It’s kind of like sealing a letter in an envelope before sending it through the mail.

SSL certificates keep online interactions private even though they travel across the public Internet, and they help customers gain the confidence to provide personal information on your website. If you ask users of your website to sign in, enter personal data such as credit card numbers, or view confidential information such as health benefits or financial accounts, you need to keep the data private.

Encryption is a mathematical process of coding and decoding information. The number of bits (40-bit, 56-bit, 128-bit, 256-bit) tells you the size of the key. Like a longer password, a larger key has more possible combinations. In fact, 128-bit encryption is one trillion times stronger than 40-bit encryption. When an encrypted session is established, the strength is determined by the capability of the web browser, SSL certificate, web server, and client computer operating system.