Systems, methods, and computer-readable storage media for encrypting communications containing or referencing globally unique identifiers to prevent unauthorized access to content item data, such as through spoofing or ancillary information leakage. An example system configured to practice the method identifies a communication, between a storage environment and a client device, associated with a globally unique identifier for a content item stored in at least one of the storage environment and the client device. The content item can be addressable via a globally unique identifier. Prior to transmitting the communication, the system can encrypt a portion of the communication containing the globally unique identifier using an encryption key based on a client-specific key and a secret version-specific key to yield an encrypted communication, and transmit the encrypted communication to the client device.