data safety in excel
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If protecting workbook in ms excel (2010, 2007, 2003) is enough safe for a sensitive data?
There is a possibility to choose encryption aes 128 bit in ms excel 2003 and 2007 (as default), from that what I read there is a possibility to choose aes 256 bit in ms 2010. But if I choose aes 256 bit in ms excel 2010., if I would have a possibility to open in ms excel 2007/2004? There are available some special applications to open protected Excel files, they work for sure with ms excel 2003. How it is with newer version of excel? How long should be password? 20 characters would be enough for workbooks with sensitive data?