I recently collaborated with Patrick Townsend, CTO Townsend Security, on an encryption key management white paper. The paper is targeted at the IBM i audience but actually contains useful information for folks using any platform.
The paper discusses the concepts of dual control, separation of duties and split-knowledge which are core principals for protecting sensitive data such as encryption keys. There are numerous choices for key management solutions on the market today. You want to make sure that that the solution you choose implements these principals fully. If not, you may find it difficult to pass audits for certain standards (e.g. DSS PCI, FIPS 140-2, etc).
Click here to download White Paper: Encryption Key Management for IBM i.