What is the role of the decoder assembly code in the optimized shellcode?

The decoder is a small piece of machine code placed at the beginning of the shellcode. It uses `add eax,0x14` to align to the encrypted shellcode, then loops through each byte, XORs it with 0x44, and writes the decrypted byte back. The loop continues until it encounters the 0x90 terminator. This ensures that the original shellcode is restored in memory without any null bytes interfering with `strcpy`.