The History of SSL: How Netscape Put the Padlock on the Web
From Netscape's SSL 2.0 in 1995 through SSL 3.0 and TLS to the free certificates of today, here is how encrypted browsing became the default on the web.
When the web began to be used for commerce in the mid-1990s, it had a glaring problem. Anything a user typed, including a credit card number, travelled across the network in plain text, readable by anyone along the route. For online shopping to work, there had to be a way to protect those messages. The answer arrived in 1995, from the company that made the most popular browser of the day: Netscape.
Why the web needed encryption
The early web protocol, HTTP, had no built-in security. A web server could not prove its identity to a browser, and a browser could not hide what it sent. In 1994, Netscape Communications released Netscape Navigator, which quickly dominated the browser market. The company recognised that unless people could trust the web with payments, its commercial potential would be limited.
Engineers at Netscape, including Kipp Hickman, designed a protocol called Secure Sockets Layer, or SSL. Taher Elgamal, the company's chief scientist, is often described as the father of SSL for his role in shaping the effort. The protocol sat between the web protocol and the network connection, and it provided two things: encryption, and a way for a server to prove its identity through a certificate.
SSL 1.0, 2.0 and 3.0
The first version, SSL 1.0, was never released to the public because of serious security flaws found internally. SSL 2.0 shipped in early 1995, with Netscape Navigator 1.1. It worked, but it contained design weaknesses that researchers soon found. Among other issues, it was vulnerable to some forms of tampering with the handshake.
In 1996, a redesigned SSL 3.0 appeared, with a significant contribution from the cryptographer Paul Kocher, along with Alan Freier and Phil Karlton. It fixed the major weaknesses of the earlier version and formed the basis of the protocols used ever since.
The export problem
United States export rules at the time, described in our article on PGP and the crypto wars, treated strong encryption as a munition. Browsers sold outside the country had to use deliberately weakened encryption, with keys of 40 bits. In 1995, researchers showed that such a key could be found by brute force using a network of computers in a matter of days, and that point was repeated as further evidence of the policy's flaws. Some servers continued to support weak "export-grade" ciphers for years after the rules were relaxed in 2000, and this later led to real attacks, such as the FREAK and Logjam vulnerabilities in 2015.
One of the most instructive events came in September 1995. Two Berkeley students, Ian Goldberg and David Wagner, discovered that the random numbers that Netscape's browser used to create session keys were predictable, because they were derived from things such as the time of day and the process number. An attacker could therefore guess the key in minutes. Netscape fixed it, and the incident became a standard example of how a good algorithm can be defeated by poor implementation.
The browser interface mattered as much as the cryptography. Netscape displayed a closed padlock, or an unbroken key, when a connection was secured, which gave ordinary people a simple visual signal. That small icon taught millions of users to look for security cues before typing sensitive details, and it also gave attackers a new thing to imitate. Fake padlock images on phishing pages became a standard trick, which is why browsers later moved the real indicators out of the page content and into the address bar.
From SSL to TLS
In the late 1990s, the Internet Engineering Task Force took over the protocol to make it an open standard. The result, published in January 1999 as RFC 2246, was Transport Layer Security version 1.0. It was based on SSL 3.0 but was not interoperable with it, and the name changed from SSL to TLS. Later versions followed: TLS 1.1 in 2006, TLS 1.2 in 2008 and TLS 1.3 in 2018, each removing old weaknesses.
The old name stuck in everyday speech. People still say SSL certificate, even though the protocol in use today is TLS. The older SSL versions have been formally retired: SSL 3.0 was deprecated in 2015 following the POODLE attack in 2014.
Timeline
| Year | Milestone |
|---|---|
| 1995 | SSL 2.0 released with Netscape Navigator |
| 1996 | SSL 3.0 published |
| 1999 | TLS 1.0 standardised as RFC 2246 |
| 2015 | SSL 3.0 formally deprecated |
| 2015-2016 | Let's Encrypt begins issuing free certificates |
| 2018 | TLS 1.3 published; Chrome starts labelling plain HTTP as not secure |
Free certificates change everything
For years, certificates cost money and needed manual work, so many sites skipped them. Let's Encrypt, a free and automated certificate authority, started issuing certificates in late 2015 and rapidly grew to protect a huge share of the web. Combined with browser pressure, it made HTTPS the normal way to publish a site.
The lesson for site owners today
HTTPS is no longer optional. Browsers warn visitors about sites that do not use it, search engines treat it as a basic expectation, and forms and logins are unsafe without it. But having a certificate is only part of the job.
- Redirect all HTTP traffic to HTTPS.
- Check that your server supports modern TLS versions and disables old ones.
- Let certificates renew automatically and monitor their expiry.
- Fix mixed content, where an HTTPS page loads resources over plain HTTP.
The hosting plans overview shows the available options.
Included with your hosting
All Zebra Hosting plans include free SSL certificates from Let's Encrypt, and Cloudflare CDN is available on hosted sites. Our SSL page explains the details, and our hosting plans overview shows what each plan includes.
