We introduce the broadband reconfigurable intelligent surface (RIS) channel (BRISC) dataset. The dataset comprises measurements of channel state information (CSI) collected at 5.53 GHz using a 256-element RIS with binary states. In the measurement campaign, the transmitter and receiver are two software defined radios (SDRs), phase-synchronized via an OctoClock, where the transmitter (receiver) is equipped with one (two) antenna(s). To manage complexity, the RIS elements are grouped into blocks of different sizes, where all elements within a block share the same state. CSIs have been captured for multiple a) transmitter positions (and fixed receiver location), b) pilot block sizes, and c) state configurations. Furthermore, we calibrated the parameters of state-of-the-art RIS channel models to fit the measured CSI. With approximately 10000 configurations explored per transmitting position, BRISC serves as a robust benchmark in communication applications. We also show here an example of its use for physical-layer authentication.