Data storage operation commands are digitally signed to enhance data security in a distributed system. A data storage client and a compute-enabled data storage device may share access to a cryptographic key. The data storage client uses the cryptographic key to digitally sign commands transmitted to the data storage device, which can use its copy to verify a digital signature of a command before fulfilling the command. The storage device can also determine whether to perform a transformation, such that requests authenticated to a first identity might receive cleartext while a request authenticated to a second identity might receive ciphertext. The compute-enabled storage device can also receive unauthenticated calls and attempt to retrieve the appropriate key from a key management service or other such source.