A method includes: decrypting, in a device, a first subset of encrypted data using a cryptographic device key associated with the device to produce first plain text, where a set of encrypted data comprises the first subset of encrypted data and a second subset of encrypted data, and where the first subset of encrypted data and the second subset of encrypted data each contain less encrypted data than the set of encrypted data and are different from each other; decrypting, in the device, the second subset of encrypted data using the cryptographic device key to produce second plain text; encrypting, in the device, the first plain text using a first ephemeral key to produce first re-encrypted data; and encrypting, in the device, the second plain text using a second ephemeral key to produce second re-encrypted data, the second ephemeral key being different from the first ephemeral key.