Securing Customer Data with SSL and HTTPS

What HTTPS protects and what it does not

Every time a customer types a password, an address or a card number into your site, that data travels across networks you do not control: home routers, public Wi-Fi, internet providers and transit links. Without encryption, anyone in that path can read or modify it. HTTPS, which is HTTP running over TLS (the protocol still widely called SSL), provides three protections:

• Confidentiality. Traffic is encrypted, so intermediaries see only that a connection exists to your domain, not the pages or form contents.
• Integrity. Any modification in transit is detected, which prevents injected ads, malware or altered prices.
• Authentication. The certificate proves that the browser is talking to a server authorised for your domain, not an impostor.

HTTPS does not protect data once it reaches your server. Databases, backups, logs and admin panels need their own security: access control, encryption at rest, patching and careful retention. HTTPS is a necessary baseline for handling customer data, not a complete privacy programme. Depending on your location and industry, regulations and payment card rules may set further requirements; this article is general guidance, not legal advice.

How TLS secures a connection

When a browser connects, it and the server perform a TLS handshake. The server presents its certificate, which contains its public key and is signed by a certificate authority (CA) the browser trusts. The browser checks that the certificate covers the requested hostname, has not expired and chains to a trusted root. Both sides then agree on session keys, and everything that follows is encrypted with fast symmetric ciphers.

Modern deployments should support TLS 1.2 and TLS 1.3 and disable SSL 3.0, TLS 1.0 and TLS 1.1, which are deprecated. TLS 1.3 removes many older options and usually completes the handshake in fewer round trips, so security and speed improve together.

Choosing the right certificate

Certificates differ in how the CA verifies you and in how many names they cover. All of them provide the same strength of encryption.

Free DV certificates from CAs such as Let’s Encrypt, issued through the ACME protocol, are trusted by all major browsers. Paid certificates may add support, warranties or organisation validation, but they do not make the encryption stronger. For the trade-offs of covering many subdomains, read understanding SSL wildcard certificates, and consider publishing CAA records to limit which CAs may issue for your domain.

Migrating from HTTP to HTTPS step by step

If parts of your site still load over plain HTTP, migration should not wait. Browsers label HTTP pages that collect input as not secure, many modern browser features only work in secure contexts, and every form submitted over HTTP exposes customer data. The migration itself is routine when done in order.

1. Inventory and prepare

List every hostname you serve: the apex domain, www, shop, api, staging and any CDN or asset domains. Crawl the site to find hard-coded http:// links, images, scripts, iframes and third-party embeds. Note which ones support HTTPS.

2. Issue and install certificates

Use your host’s built-in automation or an ACME client. With Certbot on a typical Nginx server, issuance and configuration can look like this:

sudo certbot --nginx -d example.com -d www.example.com
sudo certbot renew --dry-run

The dry run confirms that automatic renewal will work. Many control panels and managed hosts perform these steps for you.

3. Fix mixed content

An HTTPS page that loads scripts or styles over HTTP is mixed content; browsers block or warn about it. Update internal links and asset URLs to https:// or root-relative paths, update database-stored URLs in your CMS, and replace third-party resources that do not support HTTPS.

4. Redirect HTTP permanently

Every HTTP URL should return a single 301 redirect to the same path on HTTPS, preferably to your preferred hostname in one hop:

server {
    listen 80;
    listen [::]:80;
    server_name example.com www.example.com;
    return 301 https://www.example.com$request_uri;
}

Avoid redirect chains such as http to https to www, and never redirect everything to the homepage, which loses page-level relevance.

5. Update SEO signals

• Change canonical tags, hreflang annotations and Open Graph URLs to HTTPS.
• Regenerate your XML sitemap with HTTPS URLs and submit it.
• Add the HTTPS property in Google Search Console, or use a domain property that covers both protocols.
• Update links in profiles, ads, email templates and other places you control.

Rankings may fluctuate briefly while search engines recrawl; with clean 301s this typically settles, though timing varies by site size and crawl frequency.

6. Enable HSTS once stable

HTTP Strict Transport Security tells browsers to use HTTPS for your domain automatically, closing the window in which a first HTTP request could be intercepted. Start with a short max-age, confirm every subdomain works over HTTPS, then increase it. Our guide on implementing HSTS explains preload and the risks of committing too early.

add_header Strict-Transport-Security "max-age=300" always;

Hardening the configuration

Installing a certificate is the start. A solid HTTPS setup also includes:

• Only TLS 1.2 and 1.3 enabled, with modern cipher suites; your web server’s or provider’s recommended defaults are usually a good baseline.
• A full certificate chain served, so clients do not fail on missing intermediates.
• Secure cookie flags: Secure, HttpOnly and an appropriate SameSite value on session cookies.
• HTTPS between your CDN or load balancer and the origin as well, not only at the edge.
• Private keys readable only by the server process and never committed to repositories.

Free online TLS testing tools and openssl help verify the result:

openssl s_client -connect www.example.com:443 -servername www.example.com
echo | openssl s_client -connect www.example.com:443 -servername www.example.com 2>/dev/null | openssl x509 -noout -dates

Testing after the migration

Once redirects and HSTS are in place, verify the result from the outside rather than trusting your own browser, which may have cached old redirects or certificates. A short test plan helps:

• Request a sample of old HTTP URLs, including deep pages, images and PDFs, and confirm each returns one 301 to the matching HTTPS URL.
• Check both the apex and www hostnames over HTTP and HTTPS so all four combinations end at your preferred version.
• Submit a test order or form in a private window and watch the developer console for mixed content or blocked requests.
• Confirm that payment callbacks, webhooks and API clients still reach the right endpoints; some integrations do not follow redirects.
• Review Search Console coverage reports over the following weeks for unexpected errors.

curl -sI http://example.com/some-page | grep -i -E "^(HTTP|location)"

Renewals, expiry and monitoring

An expired certificate turns a trusted checkout into a full-page browser warning, and most customers will leave rather than click through. Public TLS certificates have a maximum validity that the CA/Browser Forum has been shortening in stages over the next few years, so manual renewals become impractical. Automate renewal, then monitor independently, because automation fails quietly: a changed DNS record breaks validation, a firewall blocks the ACME challenge or a server is migrated without its renewal job.

TLDix can track SSL expiry for your sites alongside domain expiry in your panel, sending alerts before either lapses. A domain expiring takes the certificate and site down with it, so monitoring both in one place is simpler.

Common mistakes to avoid

• Leaving the www or apex variant without a valid certificate.
• Using 302 temporary redirects instead of 301 permanent redirects.
• Forgetting API endpoints, subdomains or webhook URLs during migration.
• Enabling long HSTS max-age or preload before every subdomain supports HTTPS.
• Assuming the padlock means the site is secure overall; it only covers the connection.
• Relying on one person’s calendar reminder for certificate renewals.