What is an SSL Server Certificate? We clarify

An SSL Server Certificate is the basis for encrypting a website by the operator. It not only serves communication but also ensures secure authentication of a website. This prevents unauthorized interception of information and impersonation of a false identity - a common practice in phishing attacks. For a website visitor, an SSL Server Certificate does not change anything but provides high security.

SSL Server Certificate is now considered the standard for a secure internet

For a long time, website operators paid relatively little attention to encrypting websites unless it involved sensitive data such as payment information. One reason for this was the high costs associated with an official SSL Server Certificate for a long time, which did not justify the benefits for individuals. Even major providers like Facebook used unencrypted connections for many years, posing a significant security risk in open Wi-Fi networks. Since 2014, this situation has changed significantly, partly due to pressure from corporations like Google and Microsoft, as well as browser providers like Mozilla Firefox. Encryption is now considered an important ranking criterion, and browsers have been warning strongly against websites without a valid SSL Server Certificate since around 2017.

How is an SSL Server Certificate Structured?

An SSL Server Certificate can store its information in binary or text form. It consists of one or more files that include the certificate itself as well as the public and private keys. The details of a certificate include:

• Unique, individual serial number
• Owner of the certificate, for example, the company name
• Certified domain (URL)
• Validity period
• Technical details of the algorithms used
• Issuer (CA)
• Certification authority's signature
• Fingerprint
• Public key

These details are initially provided to the browser when visiting a site, so it can verify the SSL Server Certificate and confirm its authenticity. Additionally, it establishes an initial secure connection using the public key and exchanges a randomly generated session key with the other party. An SSL Server Certificate also includes a highly confidential private key, which may be stored in a separate file with the extension .key. This key is the counterpart to the public key and should never be disclosed or stored in a publicly accessible directory.

Different Providers and the Wildcard Certificate

To uniquely authenticate the owner of a certificate, it must come from an official Certification Authority (CA). When issued, the CA verifies that the applicant is the owner of a website or has unrestricted access to the server used. Until 2015, this process was done manually, making it slow and expensive. To establish encryption on the internet as a standard, the non-profit Certification Authority Lets Encrypt has been offering a free SSL server certificate for website owners since then. Since 2018, this also includes a Wildcard certificate that covers multiple subdomains that would otherwise require individual SSL server certificates. In an SSL certificate comparison, Lets Encrypt usually ranks high due to its free offering.

Possible Disadvantages and Alternatives

On the internet, HTTPS in conjunction with an SSL server certificate has become established due to its ease of use for visitors and its security. Alternatives are complex and require specific technical knowledge to implement. In practical use, the process has very few disadvantages - encryption slightly increases the resource consumption of both parties. It is up to each Certification Authority to verify their customers in different ways. Free providers like Lets Encrypt only offer a technical verification of the operator, for example, via the DNS server or website, but not a general certification of companies. This service is only provided by commercial providers, whose costs can be determined in an SSL certificate comparison.

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