Network Appliance executives said the deal would expand the company's portfolio of data protection products, including systems for disk backup and recovery and data replication software.
Decru makes encryption and authentication appliances to protect various storage environments.
"In an era where data is a precious asset and security threats to that data are accelerating, encryption is a key element of any data infrastructure," NetApp CEO Dan Warmenhoven said in a statement.
The deal is expected to close by October. Decru will be a new business unit within NetApp. According to the company, Decru will remain committed to maintaining its partnerships with other storage and networking vendors.
Earlier this week, SC Magazine reported that Institutional Shareholder Services (ISS), which influences institutional and corporate investors with analysis and recommendations, is supporting Symantec's proposed $13.5 billion acquisition of storage supplier Veritas Software.