Security protocols are frequently accelerated by implementing the underlying cryptographic functions in reconfigurable hardware. However, unprotected hardware implementations are susceptible to side-channel attacks, and Differential Power Analysis (DPA) has been shown to be especially powerful. In this work, we evaluate and compare the effectiveness of common hiding countermeasures against DPA in FPGA-based designs, using the Whirlpool hash function as a case study. In particular, we develop a new design flow called Isolated WDDL (IWDDL). In contrast with previous works, IWDDL isolates the direct and complementary circuit paths, and also provides DPA resistance in the Hamming distance power model. The analysis is supported using actual implementation results.