- We focus on secure data exchange among a group of wireless clients. The clients exchange data by broadcasting linear combinations of packets over a lossless channel. The data exchange is performed in the presence of an eavesdropper who has access to the channel and can obtain all transmitted data. Our goal is to develop a weakly secure coding scheme that prevents the eavesdropper from being able to decode any of the original packets held by the clients. We present a randomized algorithm based on Generalized Reed-Solomon (GRS) codes. The algorithm has two key advantages over the previous solutions: it operates over a small (polynomial-size) finite field and provides a way to verify that constructed code is feasible. In contrast, the previous approaches require exponential field size and do not provide an efficient (polynomial-time) algorithm to verify the secrecy properties of the constructed code. We formulate an algebraic-geometric conjecture that implies the correctness of our algorithm and prove its validity for special cases. Our simulation results indicate that the algorithm is efficient in practical settings. 2014 IEEE.