It looks like you got this document from your friend using Microsoft Excel. The document was encrypted using encrypted method that LibreOffice does not understand.
There is also free (as money) version of Microsoft Excel Viewer: https://www.microsoft.com/en-us/download/details.aspx?id=10 you can open and print a Excel document. Because you are on Ubuntu that means installing Wine and then inside Wine install this program. So from terminal:
(1) Install wine:
sudo apt-get install wine
(2) Download Excel Viewer from above web page.
(3) Install Microsoft Excel Viewer:
If you are exchanging sensitive files with your friends, you could also use encryption of some external program like OpenSSL, see details: https://stackoverflow.com/questions/16056135/how-to-use-openssl-to-crypt-decrypt-files - so creating spreadsheet file with Microsoft Office or LibreOffice and then encrypt document using openssl library.