Embedded multi-core systems are implemented as systems-on-chip that rely on packet store-and-forward networks-on-chip for communications. These systems do not use buses nor global clock. Instead routers are used to move data between the cores and each core uses its own local clock. This implies concurrent asynchronous computing. Implementing algorithms in such systems is very much facilitated using dataflow concepts. In this work, we propose a methodology for implementing algorithms on dataflow platforms. The methodology can be applied to multi-threaded, multi-core platforms or a combination of these platforms as well. This methodology is based on a novel dataflow graph representation of the algorithm. We applied the proposed methodology to obtain a novel dataflow multi-core computing model for the secure hash algorithm-3. The resulting hardware was implemented in FPGA to verify the performance parameters. The proposed model of computation has advantages such as flexible I/O timing in term of scheduling policy, execution of tasks as soon as possible, and self-timed event-driven system. In other words, I/O timing and correctness of algorithm evaluation are dissociated in this work. The main advantage of this proposal is the ability to dynamically obfuscate algorithm evaluation to thwart side-channel attacks without having to redesign the system. This has important implications for cryptographic applications. Also, the dissertation proposes four countermeasure techniques against side-channel attacks for SHA-3 hashing. The countermeasure techniques are based on choosing stochastic or deterministic input data scheduling strategies. Extensive simulations of the SHA-3 algorithm and the proposed countermeasures approaches were performed using object-oriented MATLAB models to verify and validate the effectiveness of the techniques. The design immunity for the proposed countermeasures is assessed. / Graduate / 2020-11-19