在ObjC / C中隐藏/加密字符串的最佳方法是什么？

I have a string in my code that I use as a secret when I communicate with my server. What is the best way to encypt this string to ensure that a hacker will not be able to find it out by searching my binary or looking into the memory during run time? (if possible to prevent at all?)I have a string in my code that I use as a secr