text: Key servers can have the following characteristics: 
  
  (cid:2) Physical access to the system is not required to perform a rekey operation. 
  
  (cid:2) Support for businesses that have security requirements that preclude use of USB ports. 
  
  (cid:2) Possibility to use hardware security modules (HSMs) for encryption key generation. 
  
  (cid:2) Ability to replicate keys between servers and perform automatic backups. 
  
  (cid:2) Implementations follow an open standard (Key Management Interoperability Protocol - 
  KMIP) that aids in interoperability. 
  
  (cid:2) Ability to audit operations related to key management. 
  
  (cid:2) Ability to separately manage encryption keys and physical access to storage systems. 
  
  USB flash drives have the following characteristics: 
  
  (cid:2) Physical access to the system might be required to process a rekey operation. 
  (cid:2) No moving parts with almost no read or write operations to the USB flash drive. 
  (cid:2) Inexpensive to maintain and use. 
  (cid:2) Convenient and easy to have multiple identical USB flash drives available as backups. 
  
  **Important:**Maintaining confidentiality of the encrypted data hinges on security of the 
  encryption keys. Pay special attention to ensure secure creation, management, and 
  storage of the encryption keys. 