Provided are a method, system, and article of manufacture in which a non-reversible signature of a symmetric cryptographic key is computed, wherein the symmetric cryptographic key is used to symmetrically encrypt data at rest in a storage device. The non-reversible signature is stored in association with the symmetrically encrypted data at rest in the storage device. The non-reversible signature is used to determine validity of a cryptographic key provided by a host for accessing the symmetrically encrypted data at rest in the storage device.