My working framework builds meaning by:

1. using sequences of adjacent whole anagrams,
2. requiring the anagrams to be interconnected to each other by their meaning or sense,
3. expecting the resultant words and message to develop Nostradamus' text for that line or verse,
4. finding key anagrams that have low recurrence elsewhere,
5. accepting that Nostradamus text is meaningful and that words and spelling are purposefully chosen,
6. the interwoven consistency across and between all the verses in Nostradamus' Prophecies,
7. relying on Nostradamus having used a past, present and future framework to give his code strength.
   

Why has the code remained hidden if the method is as simple as both Nostradamus and I suggest? Because it involves one single mind-boggling step and three commonly used moves to transform the original message into the new.  The three moves, used since ancient times, are:

1.  split the letters into different groups and

2. rearrange them within those new groups

3. to form a new message.  

"By means of this, past, present and future become one eternity, for all things are naked and open."
 Nostradamus in his Preface to the Prophecies 1555