officecrypto-tool

officecrypto-tool is a library for js that can be used to decrypt and encrypt office(excel/ppt/word) files..

Special Notes

The implementation of this library refers to xlsx and xlsx-populate, especially xlsx-populate, part of the source code reference and directly copied over.

Now it supports encryption and decryption of MS office and WPS files, Support doc docx xls xlsx ppt pptx decryption, support xls decryption in BIFF8 and BIFF5 formats. support docx xlsx pptx encryption.

Contents

• officecrypto-tool
  • Special Notes
  • Contents
  • Install
  • Examples
  • Supported encryption methods
    • OFFICECRYPTO specs
    • Other
  • Tests
  • Todo
  • Resources
    • In other languages

Install

npm/yarn/pnpm install officecrypto-tool

Examples

const officeCrypto = require('officecrypto-tool');
const fs = require('fs').promises;

//decrypt a file with a password
(async ()=>{
        const input = await fs.readFile(`pass_test.xlsx`);
        const output = await officeCrypto.decrypt(input, {password: '123456'});
        await fs.writeFile(`out_success.xlsx`, output);
})()

//Setting up encrypted files with passwords
(async ()=>{
        const input = await fs.readFile(`test.xlsx`);
        const output = officeCrypto.encrypt(input, {password: '123456'});
        await fs.writeFile(`standard_out_success.xlsx`, output);
})()

//Determine whether excel file is encrypted or not, support xls and xlsx format, encrypted is true, not encrypted is false.
(async ()=>{
        const input = await fs.readFile(`encrypted_test.xlsx`);
        const isEncrypted = officeCrypto.isEncrypted(input);
        // output: true

        const input1 = await fs.readFile(`not_encrypted_test.xlsx`);
        const isEncrypted1 = officeCrypto.isEncrypted(input1);
        // output: false
})()

Supported encryption methods

OFFICECRYPTO specs

• [x] ECMA-376 (Agile Encryption/Standard Encryption)
  • [x] MS-DOCX (OOXML) (Word 2007-2016)
  • [x] MS-XLSX (OOXML) (Excel 2007-2016)
  • [x] MS-PPTX (OOXML) (PowerPoint 2007-2016)
• [x] Office Binary Document RC4 CryptoAPI
  • [x] MS-DOC (Word 2002, 2003, 2004)
  • [x] MS-XLS (Excel 2002, 2003, 2004) (experimental)
  • [x] MS-PPT (PowerPoint 2002, 2003, 2004) (partial, experimental)
• [x] Office Binary Document RC4
  • [x] MS-DOC (Word 97, 98, 2000)
  • [x] MS-XLS (Excel 97, 98, 2000) (experimental)
• [x] XOR Obfuscation
  • [x] MS-XLS
  • [] MS-DOC
• [ ] ECMA-376 (Extensible Encryption)

Other

• [ ] Word 95 Encryption And Decryption (Word 95 and prior)
• [ ] Excel 95 Encryption And Decryption (Excel 95 and prior)
• [ ] PowerPoint 95 Encryption And Decryption (PowerPoint 95 and prior)

PRs are welcome!

Tests

Now that the files referenced by the test use case have been modified to submodule dependencies, if you have not downloaded the submodule dependencies, execute the following command:

-> tests/

1: git submodule init
2: git submodule update

Then check to see if the test_files directory is already in the tests directory and if all the files in it are there.

With Jest:

pnpm i 
pnpm run test

Todo

• [x] Add tests
• [x] Support decryption and encryption with passwords
• [x] Support older encryption schemes
• [x] Add decryption tests for various file formats
• [x] Support frontend
• [ ] Support more encryption and decrytion

Resources

• Technical Documents https://learn.microsoft.com/en-us/openspecs/office_file_formats/MS-OFFFFLP/6ae2fd93-51fc-4e75-a54a-1b175c627b51

In other languages

• https://github.com/opendocument-app/OpenDocument.core/blob/233663b039/src/internal/ooxml/ooxml_crypto.h
• https://github.com/qax-os/excelize
• https://github.com/nolze/msoffcrypto-tool