NetApp is talking up Brocade's encrypting switches, which include technology that Brocade licensed from NetApp/Decru as a replacement for DataFort. Decru customers that wanted to encrypt data at rest on their disk arrays could also get encryption add-ons from Cisco for MDS or use Emulex's encryption option for their HBAs. Frankly I'm not a believer that this kind of encryption at rest actually prevents much data loss, but if you are, you still have options.
Datafort was the last of what, for a while, appeared to be an industry of encryption appliances from deceased vendors like Kasten Chase and NeoScale (snapped up by nCipher, which was itself absorbed by French defense contractor Thales). While Thales continues to sell the Cryptostor tape encryptor, I don't understand why anyone would buy one.
If you come to the reasonable decision that it's time to start encrypting tapes, you could get a Cryptostor and continue to use your old tape library. Alternatively, you could spend the same money replacing the drives in the library with LTO-5 drives that have built-in encryption and spend less on tapes in the future since the LTO-5s store 2 to 16 times as much data as my old drives. Heck, you might even save on maintenance.
The end of Decru's market life is also a commentary on NetApp's ability to manage acquisitions. The truth is, some organizations are better at acquiring technologies and making them their own than others. Cisco's leading position in the Ethernet switching business came through the acquisition of switch pioneer Kalpana, (along with a few competitors), and while most storage guys think of Clariion as a pure EMC product, it was initially developed down the road at Data General.