The market for SSL security certification continues to grow and the big winner in terms of share is VeriSign, according to the latest report on SSL from Netcraft.

The study reports that VeriSign (NASDAQ: VRSN), holds a 44.4 percent share of the SSL market for June of 2010. The June figure represents an increase over the 38.1 percent share reported by Netcraft for VeriSign in May, though there is a catch. The June Netcraft SSL survey reported a more comprehensive view of the overall marketplace, thanks in part to data provided by VeriSign. The new data comes at a critical time for VeriSign's SSL business as it is in the process of being acquired by Symantec (NASDAQ: SYMC) for $1.28 billion.

"The survey process is the same, but last month VeriSign provided us with a list of hostnames for which they've issued certificates, which they've not done in the recent past," Netcraft spokesperson Mike Prettejohn told InternetNews.com.

In total, Netcraft reported on a total of 1,502,281 SSL certificates of which 667,429 were delivered by VeriSign. Fran Rosch, VeriSign's senior vice president of business authentication, explained to InternetNews.com that Netcraft relies on its own proprietary crawler to find external-facing SSL certificates, but it is not able to find every certificate because of how they are configured.

"Over the years, many SSL suppliers have actually provided Netcraft with their customer list to ensure that Netcraft finds them and reports them as installed base," Rosch said. "Until last month, VeriSign had never provided Netcraft with our customer list so our installed base was being regularly under-reported in comparison to our competition."

Even with the new data provided by VeriSign, Rosch said that it's not inclusive of all the SSL certificates the company issues.

"As VeriSign has a large share of large enterprise customers who use many of our certificates behind the firewall, we know that Netcraft continues to under report VeriSign SSL certs," Rosch said. Specifically, Rosch said VeriSign actually has almost twice as many certifications in the market than Netcraft credits the company with having.

As a publicly traded company, VeriSign provides data on its SSL install base on a quarterly basis. Rosch noted that as of March 31, 2010, VeriSign reported over 1.2M active certificates in the market. "This is almost twice as many certificates as Netcraft can find because they do not have our entire customer base and they cannot find certs behind the firewalls of our customers," he added.

So far, Rosch said that VeriSign has seen a 3 percent increase in Q1 2010 over Q4 2009 in its SSL certificate base. Renewal rates for SSL certs are also strong, according to Rosch

"VeriSign continues to see strength in our renewal rates with improving trends year-to-date," Rosch said. "The strong renewal rates are due to many factors including an improving economy, increased product functionality and maniacal focus on customer satisfaction."

With the pending sale of VeriSign's SSL business to Symantec, existing customers will continue to get the same technology and won't need to migrate platforms.

"There will be no migration required as Symantec is buying all of the infrastructure assets and public roots to operate the business as usual requiring no customer action," Rosch said.

Sean Michael Kerner is a senior editor at InternetNews.com, the news service of Internet.com, the network for technology professionals.