Battery pack for electric power tool, and battery connection device

A battery connection device that is electrically connected to a battery pack for electric power tools, the device comprising:

• an authentication data creating unit that creates authentication data;
• a conversion unit that performs a first conversion of the authentication data created by the authentication data creating unit;
• a transmission unit that transmits to the battery pack the authentication data created by the authentication data creating unit when the battery pack is electrically connected to the battery connection device;
• a receiving unit that receives from the battery pack a battery-side conversion result that is data obtained after the authentication data is converted by the battery pack;
• a reverse conversion unit that, on an assumption that the battery pack as an authentic product creates the battery-side conversion result by performing the first conversion and further a second conversion on the authentication data, performs a reverse conversion of the second conversion on the battery-side conversion result received by the receiving unit;
• and
• a determination unit that compares a result of the reverse conversion performed by the reverse conversion unit with a result of the first conversion performed by the conversion unit and determines whether or not the battery pack is an authentic product,