Data security is enhanced by receiving a request that identifies an encrypted data key, an authentication tag, and additional authenticated data that includes at least a nonce. In some cases, the authentication tag is cryptographically derivable from the encrypted data key and the additional authenticated data. A system, in some cases, determines whether the nonce is authentic and decrypts the encrypted data key by using at least a cryptographic key and the nonce, thereby resulting in a plaintext data key that is usable in various contexts.