DES cipher internals in Excel
Not long after I published AES in Excel, I decided to amuse myself again by implementing the Data Encryption Standard cipher a few months later. DES (year 1977) is a much older cipher design than AES (2001), and has rightly fallen into disuse in applications because it’s no longer secure against brute force attacks. So my spreadsheet here is more for historical interest than for practical purposes. (Heaven forbid that you are debugging a 3DES implementation...)
The input to the spreadsheet is two 16digit hexadecimal strings (each equivalent to 8 bytes), which are the plaintext block and the cipher key. Note that the key effectively has 56 bits of security, because according to the DES specification the least significant bit of each byte is ignored as padding or parity. All other parts of the spreadsheet should not be edited by the user.
Compared to AES, the structure of DES uses fewer types of primitive operations – only bitbybit permutations/
Download
The DES cipher internals spreadsheet is available in multiple formats, all with the same content and formatting:
 Microsoft Excel binary file format: descipherinternals.xls

Works in basically all versions of Microsoft Excel.
 Microsoft Office Open XML Workbook: descipherinternals.xlsx

Preferred format for Microsoft Excel 2007 and above.
 OpenDocument Spreadsheet: descipherinternals.ods

Preferred format for the opensource office suites LibreOffice and Apache OpenOffice.
More info
 Wikipedia: Data Encryption Standard
 Computer Security Learning Laboratory: Implementation of DES and AES Algorithms using Spreadsheets