A data encryption/decryption system comprising a cryptographic interface operatively coupled between a host device and a data storage device is disclosed. The host and data storage devices include respective IDE controllers supporting full ATA protocol. The cryptographic interface includes a host device-side IDE controller and a data storage device-side IDE controller, each controller supporting partial ATA protocol. The cryptographic interface also includes a cipher engine adapted to transparently perform real time data ciphering during IDE/ATA data transfer between the host and data storage devices in conjunction with the host device-side IDE controller and the data storage device-side IDE controller.