code: public static boolean cmp(byte[] a, byte[] b) {
  		if(a.length != b.length) {
  			return false;
  		}
  		for(int i = 0; i < a.length; i++) {
  			if(a[i] != b[i]) {
  				return false;
  			}
  		}
  		return true;
  	}
docs: Compare two byte arrays
  @param a byte array to compare
  @param b byte array to compare
  @return true if a and b have same length, and all the same values, false
  otherwise