Boulder, Colorado-based ProStor Systems, a developer of removable disk storage products, said Tuesday that it has added support for encryption for its products. The firm said the company's RDX systems have been certified to run with an encryption product from EncryptX, which is also based in Boulder. RDX develops a removable disk system targeted as a replacement for tape backup systems. The firm markets its products to SMB and SME customers through OEMs. ProStor is venture backed by Boulder Ventures, New Enterprise Associates, Sutter Hill Ventures, and Western Technology Investment.