Sheet Encryptor is an add-in for Excel which protects the whole spreadsheet and also encrypts any selected range of data set. As as far encryption strength is concerned, it uses user-specified encryption key to encrypt and to decrypt the Excel spreadsheets. The add-in is programmed to read external text files for encryption keys. You just have to specify the file where keys are to be extracted from and it will apply encryption over selected data values.
The add-in offers an extensive set of information regarding the encryption technique with execution time benchmark logs explaining total time spent to encrypt the document. It uses a combination of linear congruential generators of AX mod B, where A and B values are 32-bit integers selected to maximize the period of composite generator.
To install and configure the add-in, run the Sheet Encryptor.xlsm and in KEY FILE sheet, specify the location for your key file. Adjacent to KEY FILE, you will see different sheets to understand and specify linear congruential generator position, encryption key check sum registry, and to configure main settings for the add-in. Once done, save the file and open the Excel sheet which you want to encrypt.
From newly added Add-ins tab, you can access Sheet Encryptor main menu. Here, you can encrypt and decrypt whole sheet, remove current encrypt key, generate key file from memory garbage values, view key info, and read key file.
To encrypt the selected range of data sets, first select the cells you want to encrypt and click Enc button. The Dec next to it will decrypt the previously encrypted data range.
Sheet Encryptor works on Excel 2003, Excel 2007, and Excel 2010.