Dedicated Short-Range Communications (DSRC) is a wireless communication technology used in Intelligent Transport Systems for road vehicles. Applications utilizing DSRC are becoming more and more widespread, and include both vehicle-to-vehicle and vehicle-to-infrastructure systems. As this technology expands, it is important to keep security in mind. New technologies can open up new opportunities for exploitation not previously thought of. Several threats against the DSRC system for Electronic Fee Collection (EFC) have recently been presented [CEN15]. In this thesis, the possibilities for communicating with DSRC applications using a Universal Software Radio Peripheral (USRP) are explored. The open software toolkit GNU Radio is used to implement a DSRC transmitter and receiver, aiming to imitate the communication between a roadside unit (RSU) and an on-board unit (OBU). The functionality of these programs were not completely verified, but the work gives a good indication that DSRC communication should be possible with a USRP. Additionally, this thesis studies the security of the EFC system. Calculations of access credentials and authentication values are described, and weaknesses identified. The use of the Data Encryption Standard (DES) for computing these values is especially in focus. Attacks against the DES keys in EFC are presented, where customized DSRC devices are used for obtaining the values needed. To crack the encryption and retrieve the access credential and authentication keys, a modified brute-force attack is necessary. This attack is explained in detail, and an example implementation is provided. Time-memory trade-off algorithms to speed up the brute-forcing are also presented and compared.