Transport Layer Security (TLS)
Shopify uses Transport Layer Security (TLS) to secure all connections to your Shopify admin and to your store.
Transport Layer Security (TLS) is an encryption protocol used to secure communications over the internet. When a padlock icon is displayed in the address bar of your browser next to a URL that starts with
https://, then the connection uses TLS. TLS applies to all connections to Shopify, including your own connections and your customers' connections. Shopify supports version TLS 1.2 and higher of the TLS protocol.
Even though TLS replaced the older SSL (Secure Sockets Layer) protocol, the terms TLS and SSL are still used interchangeably. In other words, an SSL certificate is really a TLS certificate.
For more information, refer to Enabling secure connections to your store.