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Protect Excel using C#

Encrypt and protect Excel XLSX spreadsheet with a password and AES 256 bit encryption algorithm.

Try it Free SDK library

Protect Excel features

Encrypt and protect Excel XLSX spreadsheet with a password and AES 256 bit encryption algorithm.

C# library install

ConvertAPI provides an ASP.NET C# library that allows you to perform a Protect Excel conversion with just a few lines of code. Protect Excel documents using C# programming language with no effort at all!

NuGet Terminal >
Install-Package ConvertApi
NuGet GitHub

Authenticate ConvertAPI C# library

You can obtain your secret key by signing up for a free account. Once you sign up, you'll receive 250 free conversions instantly! Grab your authentication secret from the account dashboard, and authenticate the ConvertAPI C# library like this:

// get your secret key here: https://www.convertapi.com/a/auth
ConvertApi convertApi = new ConvertApi("secret_or_token");

Protect Excel using C# in no time!

Once you have your authentication in place, simply copy-paste this xlsx to protect conversion code snippet into your C# project:

// Code snippet is using the ConvertAPI JavaScript Client: https://github.com/ConvertAPI/convertapi-library-js

// Code snippet is using the ConvertAPI Node.js Client: https://github.com/ConvertAPI/convertapi-nodejs

// Code snippet is using the ConvertAPI PHP Client: https://github.com/ConvertAPI/convertapi-php

// Code snippet is using the ConvertAPI Java Client: https://github.com/ConvertAPI/convertapi-java

// Code snippet is using the ConvertAPI C# Client: https://github.com/ConvertAPI/convertapi-dotnet

# Code snippet is using the ConvertAPI Ruby Client: https://github.com/ConvertAPI/convertapi-ruby

# Code snippet is using the ConvertAPI Python Client: https://github.com/ConvertAPI/convertapi-python

// Code snippet is using the ConvertAPI Go Client: https://github.com/ConvertAPI/convertapi-go

REM Code snippet is using the command line utility program: https://github.com/ConvertAPI/convertapi-cli

<!-- For conversions with the multiple file result please refer to this example: https://repl.it/@ConvertAPI/HTML-Form-with-multiple-file-result -->

Try the conversion online - no coding required!

You can try out advanced conversion parameters and test the conversion result online using our interactive demo tool. This tool will produce the same conversion output as if you were using the library from your solution, and it will auto-generate the code snippet for you!

Try for FREE!

Conversion parameters

EncryptPassword String

Sets the password in the output document. Users will be asked to enter this password before MS Office allows them to view the document.

Related converters

We offer a wide range of converters beyond just DOCX to PDF that you might find useful. Whether you're working with different file formats or looking to streamline your document processing, our collection of tools is designed to make conversions quick and easy.

Data security is our top priority

We ensure that all document processing is handled securely in the cloud, adhering to industry-leading standards like ISO 27001, GDPR, and HIPAA. To enhance security even further, we can ensure that no files or data are stored on our servers and never leave your country.

Learn more about security

Businesses trust us

Highest rated File Conversion API on major B2B software listing platforms: Capterra, G2, and Trustpilot.

  • “Reliable and Scalable Conversion API for Heavy Traffic”

    ConvertAPI processes large volumes of conversions daily without issues. The documentation is well-structured, and the support team is fast, knowledgeable, and eager to assist with even edge-case issues. It scales well for growing demands.

    Artem K.,Head of Software Development

  • "A Powerful REST API That Helps us Manage Documents Easily"

    A powerful REST API that helps us easily convert all our documents from word to PDF. We decided to leave development & server management tasks for ConvertAPI and focus on what's more important for the business. We like that this API is so easy to set up and it is very reliable.

    Christopher RydahlCTO and Sr. Developer, Hublo

  • "Very Successful And Fast API"

    We have been using ConvertAPI for over two years. During this time, we have converted over 100,000 documents via this service. We find the API very successful and fast.

    Oscar BrownDirector of Development at Flocknote

  • "Great Solution For a Great Price!"

    First of all we didn't expect to have such easy integration. ConvertAPI's documentation was perfect, so we didn't have any questions while integrating it to our CRM system. Second benefit of ConvertAPI is that it gives great product for a great price.

    Edvinas kisielisIT Support Specialist, Vinted

  • “All-in-One Solution for All File Conversion Needs”

    We use ConvertAPI to convert and repair PDFs, extract text, and perform OCR. Previously, We relied on multiple APIs, but ConvertAPI simplified our workflow into one reliable solution with excellent stability and support.

    Giuseppe C.,Chief Technical Officer

  • "Great Product and Great Customer Support!"

    Great product and great customer support! Found an issue with their API, which was fixed very quickly after a brief conversation with the support - even as a free user at the time - definitely a nice versatile API!

    Dennis Aagaard MortensgaardCRM Consultant, DoWeb APS

  • "Simple Service That Does Exactly What Is Promised Every Time"

    Great documentation on their website makes it easy to get started. The support team has also been super responsive. They have a large number of plan options at decent prices. The service itself works exactly as promised and responds fast.

    JAKE, BDirector of IT and Salesforce Dev

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