A feature key is provided to enable a specific feature in a target system, such as an IBM® Enterprise Storage Server®. The key includes fields identifying at least a portion of a serial number of the target system, identifying the feature on the target system to be enabled, and identifying a quantity associated with the feature to be enabled. Including the serial number ensures that the feature key will enable the feature on only the designated system and including the quantity ensures that only the quantity (of storage space, for example) paid for by the customer will be enabled. Additional fields may also be included identifying a storage architecture on which the feature is to be enabled, identifying a machine on which the feature is to be enabled, and identifying a sequence of prior feature keys generated for the feature on the target system. Preferably, the key is encrypted with an algorithm which uses at least a portion of the serial number of the target system, thereby ensuring that the feature key may be decrypted only by the target system.