.NET 3.4.1 SDK Version: Certificate Parsing Issue on Linux: Invalid XML Signature and Schema Validation Errors

Signing process
1

When using the .NET 8 SDK in a Windows environment, everything works as expected. However, when the same application is published and deployed to a Linux environment, an issue occurs during the signing and reporting of simplified XML invoices.

Error Message Returned by SDK:

[Error] Parsing EInvoice Certificate
[Error] Populating Signed Signature Properties

Root Cause:

After investigation, the issue seems to originate from the ParseCertificateMiddleware class. Specifically, the following code:

X509Certificate2 X509Certificate2 = new X509Certificate2(
    (byte[])(object)(from x in Encoding.UTF8.GetBytes(eInvoiceData.CertificateContent)
                     select (sbyte)x).ToArray());

This works on Windows but fails on Linux due to differences in how certificate content is handled. It appears that the certificate content is base64-encoded, and decoding it with Encoding.UTF8.GetBytes leads to an invalid byte array on Linux.

Suggested Fix:

Changing the code to use proper base64 decoding instead resolves the issue across both environments:

X509Certificate2 X509Certificate2 = new X509Certificate2(
    (byte[])(object)(from x in Convert.FromBase64String(eInvoiceData.CertificateContent)
                     select (sbyte)x).ToArray());

This approach correctly handles the certificate bytes and resolves the signing and validation issues when deployed on Linux.

Request:

Kindly review and consider updating the SDK to ensure platform-independent handling of certificates. This will help avoid deployment issues in Linux-based environments.

2

Dear @kyoussef

Thanks for reaching out, Welcome to our community.

without your changing, can you please elaborate more with the below:

1- What are the exact steps that you followed?
2- What is the SDK version that you are using?

Thanks,
Ibrahem Daoud.

3

Without this modification, the dlls that sign and encrypt the invoice have different additional files depending on the operating system type and are usually located in a folder :open_file_folder: runtime