Patent ID: 7240197

Claim:
A method of controlling security of data in a storage system having a local disk system and a remote disk system that are coupled to at least one host computer, the method comprising: in the local disk system coupled to a first host computer and a management console, the local disk system having first and second volumes of storage, the first and second volumes being associated with first and second encryption keys, respectively, the first and second encryption keys being provided to the local disk system by the management console: when a write of data is to be made to the first volume of the local disk system, retrieving the first encryption key; encrypting the data using the first encryption key, the encrypting being performed by the local disk system; transferring the encrypted data to the remote disk system via a first communication link; then in the remote disk system coupled to a second host computer: determining whether the data is to be stored in an encrypted form or a decrypted form, the determining being performed by the remote disk system; determining an address for storage of the data in the remote disk system; if the data is to be stored in a decrypted form, decrypting and writing the data in the remote disk system; if the data is to be stored in an encrypted form, writing the data in the remote disk system without decrypting the data; and notifying the local disk system via the first communication link that the step of writing the data is complete, wherein the local disk system is coupled to the first host computer via a second communication link to allow the first host computer to access data stored in the local disk system, the first and second communication links being different, wherein the remote disk system includes third and fourth volumes corresponding to the first and second volumes, respectively.