Patent ID: 7921294

Claim:
A method, comprising: in response to a tape being written onto for a first time, determining, by a tape drive having the tape, whether a symmetric cryptographic key is in use to encrypt data at rest in the tape, wherein the tape drive has plurality of tapes, wherein the tape drive comprises a hardware device; computing, by the tape drive, a non-reversible signature of the symmetric cryptographic key used to symmetrically encrypt data at rest in the tape that is within a storage library having a library controller and an autochanger mechanism to transfer the tape accessible to the tape drive; storing, by the tape drive, the non-reversible signature in association with the symmetrically encrypted data at rest in the tape accessible to the tape drive; receiving, by the tape drive, a command from a host, wherein the command provides a cryptographic key to the tape drive for accessing the symmetrically encrypted data at rest in the tape; computing, by the tape drive, a signature of the cryptographic key provided by the host by using a non-reversible signature calculator; and in response to determining, by the tape drive, that the computed signature of the received cryptographic key does not match the stored non-reversible signature associated with the symmetrically encrypted data at rest, attempting, by the tape drive, for a second time to determine validity of any cryptographic key provided by the host for accessing the symmetrically encrypted data at rest in the tape.