What is SSL Email and Its Role in Email Security

Email is an indispensable tool for communication, connecting businesses with customers and people with their personal networks. And in this vast ocean of emails flowing through the internet, keeping your information safe and private is a top priority.

This is where SSL steps into the limelight as the guardian of confidential information, protecting against cyber threats. As per data from the Google Transparency Report, approximately 91% of outbound and 96% of inbound emails were subjected to encryption measures, during last month alone.

To grasp the importance of encrypted emails, let’s better understand how critical SSL is to the secure transfer of data across the internet. We will then discuss what SSL email is and how SSL benefits you as an email marketer.

What is SSL Protocol?

SSL, or Secure Sockets Layer, is a secure email communication protocol designed to secure data transmission over any computer network, most commonly the Internet. It is the protocol used to provide security to emails.

SSL mail security provides a way for web browsers and email servers to establish secure connections, ensuring data transferred between them remains confidential. An email server SSL connection encrypts the data in transit; this prevents eavesdropping and unauthorized access. Sending an email without SSL security may lead it straight to the spam folder.

The uses of SSL include:

Encryption: SSL uses encryption algorithms to scramble data before transmission and then decrypt it at the receiving end. This prevents anyone who intercepts the data from understanding its contents.
Authentication: SSL helps verify the server’s identity (and sometimes the client’s) to ensure data is exchanged only with the intended party. This is crucial in preventing man-in-the-middle attacks.
Data integrity: SSL ensures your data remains intact and unaltered during transmission. It uses complex algorithms to check for tampering.
Secure handshake: Before establishing a secure connection, SSL performs a handshake in which the client and server agree on encryption methods and exchange keys.
Certificates: SSL uses digital certificates issued by trusted Certificate Authorities (CAs) to authenticate the identity of websites and servers. These certificates contain information about the entity’s identity and public keys.

SSL has been widely used for securing web traffic, such as HTTPS connections — the “https” in a URL indicates the use of SSL.

However, it’s important to note SSL 3.0 (which launched in 1996) and its earlier versions have known security vulnerabilities. That’s why we strongly recommend you use modern versions of the protocol, referred to as TLS (Transport Layer Security) for enhanced security.

Next, let’s understand what are SSL connections.

What is SSL Connection?

An SSL connection is a secure, encrypted link established between a client — such as a browser or email client — and a server, which can be either a website or an email server.

This encrypted tunnel ensures all data transmitted between the two points remains private and protected from eavesdropping or tampering.

Email users can activate SSL on their phones — take for example, the Mail app on iPhone below.

1 iPhone Mail App Settings — iPhone Mail App Settings

3 iPhone Account Settings — iPhone Account Settings

4 iPhone Mail Advanced Settings — iPhone Mail Advanced Settings

5 SSL Settings iPhone — SSL Settings iPhone

SSL vs TLS

“SSL” remains a prevalent term due to its historical significance as the pioneering standard for internet security, even though TLS replaced it in 1999. Many companies and organizations continue to use the term “SSL” in their products and services, even though they are technically using TLS.

Let’s compare SSL and TLS to better understand their similarities and differences.

SSL vs TLS Email

This table highlights the differentiation features of SSL and TLS:

Feature	SSL	TLS
Encryption	Both provide encryption for data in transit	Both provide encryption for data in transit
Status	Deprecated	Actively being developed
Security vulnerabilities	SSL has known security vulnerabilities, especially in earlier versions	TLS addresses all the security issues present in SSL
Key exchange methods	SSL primarily uses RSA (based on RSA algorithm) for key exchange	TLS offers a variety of key exchange methods, including RSA, DH, and ECDH
Reliability	SSL tends to have lower reliability and slower performance	TLS is renowned for its high reliability and continuous improvements, resulting in reduced latency
Compatibility	SSL is generally not recommended due to security concerns	TLS is widely used for secure data transmission on the internet

SSL vs TLS Email

As you can see, SSL is officially a relic of the past, except for its name; for the rest of the article, we will continue to use SSL as it’s an industry term.

Should You Use SSL or TLS for Email Marketing?

For email marketers prioritizing secure data transmission and deliverability, TLS is the current standard. Ensure your email infrastructure and ESP enforce TLS 1.2 or higher for optimal security during server-to-server communication. While SSL is the deprecated predecessor, the term is often used interchangeably.

Email users also benefit from this encryption, safeguarding their message content.

What is SSL Communication?

SSL and its successor, TLS, are used in various applications and protocols to secure data transmission over networks.

Below are common use cases for SSL:

Web browsing: SSL is most commonly associated with securing web traffic. When you visit a website with “https” in the URL, your web browser establishes an encrypted SSL connection to the web server, ensuring data exchanged between your browser and the website remains secure. This is crucial to protect sensitive information like login credentials or personal data.
Email communication: SSL can be used to encrypt email traffic between email clients and servers, ensuring the privacy of email content and attachments. It’s also crucial in email marketing; if you plan to send a mass email, you need an SSL connection.
Virtual Private Networks (VPNs): SSL is used to establish secure VPN connections, providing a secure tunnel for remote users to access corporate networks or browse the internet with enhanced privacy.
Private email servers: If you use a private email server, you need SSL for mail server security.
Instant messaging: Some instant messaging services use SSL to encrypt chat messages and file transfers.
VoIP (Voice over IP): SSL can be used to secure VoIP communications, protecting the confidentiality of voice conversations.
Secure remote access: Many organizations use SSL for secure remote access to internal resources; this allows employees to access company networks and applications securely from remote locations all over the world.
Online payment processing: Probably one of the more critical roles SSL plays; it is vital for securing online payments and protecting credit card information during e-commerce transactions.
IoT (Internet of Things) security: In the growing field of IoT, SSL is used to secure data exchange between IoT devices and cloud services, ensuring the privacy and integrity of data collected from connected devices.

SSL is used in a wide range of applications and services where secure data transmission is essential to protect privacy.

What is an SSL Email Certificate?

An SSL email certificate, more accurately an S/MIME (Secure/Multipurpose Internet Mail Extensions) certificate, is a digital certificate allowing email marketers to encrypt their outgoing messages and digitally sign them.

Encryption ensures only the intended recipient can read the email, protecting sensitive campaign data. Digital signing verifies the sender’s identity, enhancing trust and preventing phishing, improving deliverability rates.

Types of SSL certificates

SSL certificates come in several types, each designed to serve different purposes and provide various levels of security and trust. The main types of SSL certificates include:

Domain Validated (DV) Certificates/Single Domain Certificates: These certificates validate only the domain name of a website. DV certificates are quick to obtain, usually through email verification. They are suitable for small websites and personal blogs but offer the lowest level of trust.
Organization-Validated (OV) Certificates: OV certificates verify both the domain and the organization that owns it. The CA checks the legal and physical existence of the organization. OV certificates provide a moderate level of trust and are often used by businesses and e-commerce sites.
Extended Validation (EV) Certificates: EV certificates offer the highest level of trust and are easily recognizable by the green address bar in most web browsers. The CA performs extensive verification of the organization’s legal and physical existence, as well as its right to use the domain. EV certificates are often used by banks, e-commerce sites, and other entities requiring the utmost level of security and trust.
Wildcard Certificates: Wildcard certificates secure a domain and all its subdomains with a single certificate. They are useful for organizations with numerous subdomains and reduce the administrative burden of managing multiple certificates.
Multi-Domain Certificates: Multi-Domain certificates (or Subject Alternative Name certificates) allow you to validate multiple domain names with a single certificate. This is convenient if you own multiple websites or domains.

Choosing the right type of mail server SSL certificate depends on your specific use case and the number of domains you wish to secure. Typically, for public-facing websites, EV certificates offer the highest level of trust and security, while DV and OV certificates are more common for less critical applications.

What Are Email Security Certificates?

An email security certificate, often an S/MIME certificate, is a digital credential used to secure email communication. OpenPGP certificates also act as email security certificates on certain servers.

It provides two key functions:

Encryption to ensure only the intended recipient can read the email,
A digital signature to verify the sender’s identity and ensure the message hasn’t been tampered with.

This enhances trust, prevents phishing, and protects sensitive information.

TLS Certificate vs SSL Certificate

While often used interchangeably, a TLS certificate is the modern standard, superseding the older SSL certificate.

Functionally, they achieve the same goal: securing connections through encryption and authentication. Most “SSL certificates” issued today actually support TLS protocols.

What is SSL in Mail Settings?

If you’ve been failing deliverability tests recently, it could be due to the absence of an SSL connection; it plays a crucial role as an email security protocol. Mail providers often run an email SSL check to verify senders are legit.

So you may have configured your SMTP email setup correctly, but without an SSL connection to run it on, you won’t see any improvement in inbox placement. You can detect other technical issues with a full-fledged email marketing audit or by using email deliverability services. You must ensure SSL in mail settings is correct configured.

But it’s not just about email deliverability; mailserver SSL plays an important role in securing email communications. It provides encryption and authentication for email protocols such as SMTP (Simple Mail Transfer Protocol) and IMAP (Internet Message Access Protocol), as well as for web-based email services like HTTPS.

6 Ways in Which SSL is Utilized in Emails

Encryption: SSL encrypts the content of emails, making it unreadable to anyone intercepting them. This ensures the confidentiality of email content during transmission over the Internet or internal networks.
Authentication: An SSL certificate for email server authenticates its identity. This helps prevent email spoofing, where malicious actors pretend to be legitimate email servers, by ensuring the sending and receiving servers are who they claim to be. Authentication also helps verify emails, marking email marketers as trusted senders. Some ESPs may not even send emails unless you use an SSL connection, leading to queued emails or deferred emails.
User verification: SSL can be used to encrypt the authentication process when a user logs in to an email server. This is important for protecting login credentials (username and password) from being intercepted by attackers.
Server-to-server communication: When an SSL mail server communicates with another while sending and receiving messages between different domains, connections are more secure.
Webmail services: Popular webmail services like Gmail, Outlook, and Yahoo Mail use SSL to secure the web interfaces through which users access their emails. When you log in to your email account through a web browser, you are on a secure SSL webmail connection.
Email clients: Clients such as Microsoft Outlook and Apple Mail can be configured to use SSL for sending and receiving emails. This ensures your emails are encrypted during transit.

Now that we better understand what’s SSL for email, we can see its role in protecting the confidentiality of email content. While it clamps down on man-in-the-middle attacks, it does not do much against phishing emails or spoofing. But those issues can be fixed by adding authentication protocols such as SPF, DKIM, and DMARC to your email domain.

Is SSL Email Important for Email Marketers?

SSL plays a critical role in securing all the information transferred between you and your email marketing subscribers. As the main email transmission protocol, using an SSL/TLS connection also makes you seem more legitimate to mail services.

SSL is equally important on websites. If your domain’s TLS/SSL certificates are not up-to-date, check domain reputation — it should be low. Similarly, an unsecured checkout process may cause trust issues, which can affect conversions. Customers love a website with a robust privacy policy!

SSL is also important for encrypting usernames or passwords, as well as any form of data your customers submit to your website. The last thing you want is your customer’s personal information to leak online.

SSL is Critical in Email Marketing

Secure email marketing is a non-negotiable in 2025.

Below are 5 compelling reasons why you should adopt them ASAP:

Data security: SSL encryption ensures the content of email messages, including subscriber data, is transmitted securely. This is particularly important for protecting sensitive customer information.
Subscriber privacy: Using an SSL email server helps reassure subscribers that their personal information is handled securely, which can lead to increased trust and engagement with your emails.
Deliverability: Many internet service providers (ISPs) and email service providers (ESPs) prioritize the delivery of emails encrypted and authenticated with SSL. This can improve email deliverability by reducing the chances of your messages getting caught in spam filters. For example, at Campaign Refinery, we enable SSL by default on our email links (URLs) to give subscribers added confidence when clicking tracking links from our system.
Credibility: Sending emails via secure and authenticated connections enhances your emails’ credibility and is beneficial for email branding.
Maintaining reputation: A positive reputation is crucial for email marketers. Using SSL can prevent unauthorized use of your domain and protect your brand’s reputation from cybercriminals who may try to impersonate your email communications.

As you can see, SSL is important for the success and integrity of your email marketing campaigns. It enhances security, privacy, and builds subscriber trust; this can lead to better deliverability and higher email engagement. Ensure you run an email SSL test periodically to ensure its working as intended.

How to Get an SSL Certificate for Your Website

Viewing Google's site security on Firefox — Viewing Google’s site security on Firefox

If you’re convinced of the benefits of SSL and are keen on getting certification for your website, here’s how to do it:

Identify your needs: Determine your website’s security requirements, including the type of certificate and the number of domains/subdomains you need to secure.
Choose a reputable certificate authority (CA): Select a trusted CA to purchase your SSL certificate. Common CAs include DigiCert, Comodo Group, and GlobalSign.
Generate a certificate signing request (CSR): Create a CSR on your web server to request the SSL certificate. This includes your server’s public key and domain information.
Order and validate: Order the SSL certificate from the CA’s website and complete the validation process. This may involve confirming your domain ownership or organization details. Remember, when you apply for an SSL certificate for a domain, the CA will verify your ownership of your domain by examining the domain’s WHOIS record.
Receive and install the certificate: Once approved, you’ll receive the SSL certificate files from the CA. Follow the CA’s instructions and install these files on your web server.
Configure your server: Adjust your web server’s settings to enable SSL, specifying the certificate and private key locations.
Update website links: Ensure all resources (e.g., images, stylesheets) are loaded via HTTPS to prevent mixed content warnings.
Test your configuration: Use online tools to check your SSL setup and ensure it’s secure.
Enable HTTPS: Update your website URLs to use “https” to secure all user connections.

The exact steps and requirements can vary depending on your web hosting provider, server software, and the CA you choose. Be sure to follow their specific instructions to obtain and install your SSL certificate.

Note that some web hosting providers may offer integrated SSL certificate solutions, making the process simpler.

Campaign Refinery is the Most Secure Email Platform

Using a secure email protocol is critical, but it’s equally important to work with a trustworthy email platform.

If you’re ready to enhance your email marketing strategy and deliver the highest level of trust to your subscribers, Campaign Refinery is exactly what you’re looking for.

We’re committed to providing top-notch security, innovative features, and a seamless experience for you and your readers — if you seek top-tier email performance, you’ll find it on our platform. We offer the best SSL email hosting.

For example, we insist our clients have SSL enabled on their domains and WHOIS privacy disabled at the same time. We also insist our clients have domains with trustworthy content; it makes them look authentic plus it helps boost email sender reputation.

As you can see, we’re meticulous about choosing the clients we want to work with! You can learn more about the benefits of Campaign Refinery from our signup page.

It’s the fastest way to unlock the power of secure, impactful email marketing!

FAQ

What Does Use SSL Mean?

Using SSL means establishing an encrypted connection; SSL is used for the secure transmission of data between a client and a server.

Does HTTPS Encrypt the URL?

While the main content is encrypted, parts of the URL, specifically the domain name and sometimes the path, are typically visible.

How Do I Enable SSL for Email?

You usually configure your email client with the server names and specific SSL/TLS ports (like 993 for IMAPS or 465 for SMTPS) provided by your email provider.

Does Gmail Use SSL?

Yes, Gmail uses SSL/TLS encryption for connections between your device and its servers.

When Using SSL Authentication, What Does the Client Verify First When Checking a Server’s Identity?

The client first verifies the server’s SSL certificate against a list of trusted Certificate Authorities (CAs).

What Does SSL Mean on iPhone?

On iPhone, SSL indicates the device is establishing a secure, encrypted connection with a server, often seen when browsing websites (HTTPS) or using secure apps.

Is Gmail SSL or TLS?

Gmail primarily uses TLS for encrypting email connections.

Is SSL Secure?

While the term SSL is still common, the latest versions of TLS are considered more secure due to patched vulnerabilities in older SSL protocols. That makes TLS the most secure email protocol.

Do I Need an SSL Certificate for Email?

As an individual user, you don’t typically need to install an SSL certificate for email; your email provider handles server-side security with TLS. For email marketing for encryption and signing, you’d use an S/MIME certificate.

What is SSL Email and Its Role in Email Security