Working Group, whose first charter was to develop the Market Requirements Document (MRD) for a HomePlug Access BPL specification. The Alliance made an open invitation to the BPL industry to participate in the development of or provide input for consideration in the MRD. After several months of collaboration between utilities, ISPs and other BPL industry groups, the MRD was completed in June 2005. HomePlug's work on the Access BPL was subsequently contributed and merged into the IEEE 1901 standard. Security Since signals may travel outside the user's residence or business and be eavesdropped on, HomePlug includes the ability to set an encryption password. The HomePlug specification requires that all devices are set to a default out-of-box password although a common one. Users should change this password. If the password is not changed, an attacker can use their own homeplug device to detect the users signals, and then use the default password to access and change settings such as the encryption key used. On many new powerline adapters that come as a boxed pair, a unique security key has already been established and the user does not need to change the password, except when using these with existing powerline adapters, or adding new adapters to an existing network. Some systems support an authenticate button, allowing adapters to be added to the network with just two button presses (one of each of the devices). To simplify the process of configuring passwords on a HomePlug network, each device has a built-in master password, chosen at random by the manufacturer and hard-wired into the device, which is used only for setting the encryption passwords. A printed label on the device lists its master password. The HomePlug AV standard uses 128-bit AES, while the older versions use the less secure DES protocols. This encryption has no effect on the data the user sends or receives, and therefore higher level protocols and systems like TLS should still be used. Since HomePlug devices typically function as transparent network bridges, computers running any operating system can use them for network access. However, some manufacturers only supply the password-setup software in a Microsoft Windows version; in other words, enabling encryption requires a computer running Windows . Once the encryption password has been configured, any device supporting the ethernet specification will work on the adapter. Interoperability HomePlug AV, GP and AV2 are fully interoperable, and will also interoperate with IEEE