dynpdf_issue

This repository's only purpose is to demonstrate the Dynamic PDF Core Suite's issue when signing document with TSA using an ECDSA certificate.

Environment

• OS version: Windows 11
• .NET version: .NET Framework 4.8
• Dynamic PDF Core Suite .NET version: 12.22.0

Build & run

The console application can be built with VS2022, but older version's may work. After compiling the project, run the executable which will crash with the following:

Unhandled exception: System.NotSupportedException: The certificate key algorithm is not supported.
   at System.Security.Cryptography.X509Certificates.X509Certificate2.get_PrivateKey()
   at ceTe.DynamicPDF.Certificate.#kJ(Byte[] #xmc, #UKe #ymc)
   at #6lc.#2uc.#kJ(Byte[] #xmc, #UKe #ymc)
   at ceTe.DynamicPDF.Document.Draw(Stream stream)
   at ceTe.DynamicPDF.Document.Draw(String filePath)
   at DynamicPDF_TSA_Issue.Program.Main(String[] args) in D:\Projects\_FORNAX_\DynamicPDF_TSA_Issue\Program.cs:line 27

Certificate details

The project is using a seld-signed certificate with Elliptic Curve Digital Signiture Algorithm (ECDSA) using 384 bits private key.

The certificate was generated with OpenSSL, using the following commands:

1. Generate the 384 bits private key using secp384r1 named curve:

openssl ecparam -name secp384r1 -genkey -noout -out ec_private_key_384.pem

2. Create the certificate signing request (CSR):

openssl req -new -key ec_private_key_384.pem -out ec_csr.pem

3. Generate the self-signed certificate:

openssl req -x509 -key ec_private_key_384.pem -in ec_csr.pem -out ec_certificate_384.pem -days 365

4. Pack the private key and certificate into a PKCS#12 (.pfx) file with a tool like KeyStoreExplorer.

Assumed error

Inspecting the exception's stack trace, the DynamicPDF Core Suite library calls the X509Certificate2 class' PrivateKey property which is an obsolete method, instead, GetRSAPrivateKey(), GetDSAPrivateKey(), or GetECDsaPrivateKey() should be called.