In this paper, we introduce novel techniques to improve the performance of representative Authentication Encryption (AE) functions namely Galois/Counter Mode of operation (GCM) on modern high-end IoT platforms (ARM–NEON), which support SIMD and cryptography instruction set. The GCM requires efficient counter mode of encryption and binary field multiplication. The 128-bit binary field multiplication is optimized by re-ordering the instruction set and combining 2 64-bit operations into 1 128-bit operation. For the counter mode of encryptions, we used LEA encryption in NEON instruction sets. Finally, we achieved 16.5 cycles/byte for LEA-GCM operation.