Cryptography has an important role in data security against known attacks and decreases or limits the risks of hacking information, especially with rapid growth in communication techniques. In the recent years, we have noticed an increasing requirement to implement cryptographic algorithms in fast rising high-speed network applications. In this paper, we present high throughput efficient hardware implementations of Advanced Encryption Standard (AES) cryptographic algorithm. We have adopted pipeline technique in order to increase the speed and the maximum operating frequency. Therefore, registers are inserted in optimal placements. Furthermore, we have proposed 5-stage pipeline S-box design using combinational logic to reach further speed. In addition, efficient key expansion architecture suitable for our proposed design is also presented. In order to secure the hardware implementation against side-channel attacks, masked S-box is introduced. The implementations had been successfully done by virtex-6 (xc6vlx240t) Field-Programmable Gate Array (FPGA) device using Xilinx ISE 14.7. Our proposed unmasked and masked architectures are very fast, they achieve a throughput of 93.73 Gbps and 58.57 Gbps, respectively. The obtained results are competitive in comparison with the implementations reported in the literature.