# Copyright (c) 2010-2020 openpyxl
Create a password hash from a given string for protecting a worksheet
only. This will not work for encrypting a workbook.
This method is based on the algorithm provided by
Daniel Rentz of OpenOffice and the PEAR package
Spreadsheet_Excel_Writer by Xavier Noguer <[email protected]>.
See also http://blogs.msdn.com/b/ericwhite/archive/2008/02/23/the-legacy-hashing-algorithm-in-open-xml.aspx
password = 0x0000
for idx, char in enumerate(plaintext_password, 1):
value = ord(char) << idx
rotated_bits = value >> 15
value &= 0x7fff
password ^= (value | rotated_bits)
password ^= len(plaintext_password)
password ^= 0xCE4B