If you thought security was no longer an inhibitor to cloud adoption, think again. According to Bitglass, cloud adoption—particularly in the enterprise—is slower than thought, and much of it has do with concerns over the perceived lack of security for data and apps in the cloud.

Bitglass' "Cloud Adoption Report" noted that 52 percent of large companies and one-third of small and medium businesses (SMBs) are not moving to the cloud because of security concerns. But not only that, concerns about security are not only not decreasing; they're increasing. A previous report from October 2011 indicated 25 percent of businesses expressed some concern over cloud security, but that figure increased to 42 percent in July 2013.

"Because larger companies have more-established IT processes, they generally have a higher amount of paranoia with respect to cloud security issues. However, they also have the largest economic gains to be had from moving to cloud," said Nat Kausik, CEO of Bitglass, in a prepared statement.

But for those who have accepted the cloud as the vision of IT, cloud-based email is the "bellwether" of adoption. It's more likely for private companies to adopt cloud-based email than public companies, but of those organizations who have adopted cloud email, it looks as though Google (GOOG) has taken a lead in the market over major competitor Microsoft (MSFT).

According to Bitglass, 16.5 percent of private companies and 11.9 percent of public companies sampled had chosen Google's Gmail for its cloud email solution, but that number dropped off 7.6 percent of private companies and 8.8 percent of public companies for Microsoft cloud email offerings.

"Since public companies are generally larger and older, they are more likely to have history and substantial ties to Microsoft," Kausik said. "We believe that the lower rate of cloud adoption among public companies is due to additional regulatory and reporting burdens that private companies do not face. Given the compliance and audit capabilities lacking in most cloud apps, we expect third-party security technology will be required to help close this gap."

Bitglass is both a Google Apps and Microsoft Office 365 partner. And according to the company, it is seeing higher adoption of Google's cloud services than Microsoft's.