Very cool! This is similar to what we've built at Crypteron. Our approach, however, is to leave the data where it currently resides, be it public cloud, on-premises, or hybrid cloud, and perform the encryption at the application layer using our developer integrations in C# and Java. This reduces the circle of trust to just the application itself making compliance and auditing much simpler. We take care of key management including secure key distribution, key caching, key rotation, data migration from one key to another, multiple security partitions, and access control rules. We just launched a free Community Edition as well!
Crypteron