Implementation of the ECMA-376 Document Encryption

The implementation is split into three packages:

- This package contains common functions for both current implemented cipher modes.
- the {@link org.apache.poi.poifs.crypt.standard standard} package is part of the base poi jar and contains classes for the standard encryption ...
- the {@link org.apache.poi.poifs.crypt.agile agile} package is part of the poi ooxml jar and the provides agile encryption support.

## Related Documentation

Some implementations informations can be found under:

- Apache POI - Encryption support

@see org.apache.poi.poifs.crypt.standard @see org.apache.poi.poifs.crypt.agile