DocumentSigner.Validate(Stream, SignatureValidationOptions) Method

Validates a signature in the specified stream with the specified options.

Namespace: DevExpress.Office.DigitalSignatures

Assembly: DevExpress.Docs.v20.2.dll

NuGet Package: DevExpress.Document.Processor

NuGet Packages: DevExpress.Document.Processor, DevExpress.WindowsDesktop.Document.Processor

Declaration

C#

public PackageSignatureValidation Validate(
    Stream inputStream,
    SignatureValidationOptions options
)

VB.NET

Public Function Validate(
    inputStream As Stream,
    options As SignatureValidationOptions
) As PackageSignatureValidation

Parameters

Name	Type	Description
inputStream	Stream	The stream that contains a file to validate.
options	SignatureValidationOptions	An object that contains signature validation options.

Returns

Type	Description
PackageSignatureValidation	An object that contains validation information.

Remarks

Validation Options

The SignatureValidationOptions object allows you to specify signature validation options. Use the SignatureValidationOptions.ValidationFlags and SignatureValidationOptions.CertificateKeyUsageFlags properties to exclude validation steps.

C#

private static void ValidateSignature(Stream path)
{
    DocumentSigner validator = new DocumentSigner();

    //Specify validation options
    //In this example, certificate validation is skipped
    SignatureValidationOptions validationOptions = new SignatureValidationOptions();
    validationOptions.ValidationFlags = ~ValidationFlags.ValidateSignatureCertificate & ~ValidationFlags.ValidateTimestampCertificate;

    //Validate the signature:
    PackageSignatureValidation signatureValidation = validator.Validate(path, validationOptions);
    AnalyzeValidationResult(signatureValidation);
}

VB.NET

Private Shared Sub ValidateSignature(ByVal path As Stream)
  Dim validator As New DocumentSigner()

  'Specify validation options
  'In this example, certificate validation is skipped
  Dim validationOptions As New SignatureValidationOptions()
  validationOptions.ValidationFlags = (Not ValidationFlags.ValidateSignatureCertificate) And Not ValidationFlags.ValidateTimestampCertificate

  'Validate the signature:
  Dim signatureValidation As PackageSignatureValidation = validator.Validate(path, validationOptions)
  AnalyzeValidationResult(signatureValidation)
End Sub

Validation Process

The Validate method returns the PackageSignatureValidation instance that contains validation information. Check the PackageSignatureValidation.Result and PackageSignatureValidation.ResultMessage properties to determine whether the signature is valid.

Note

Make sure that the signature certificate is registered on your machine. Otherwise, the signature is invalid.

If the document is not signed, the PackageSignatureValidation.Result property returns SignaturesNotFound.

If the document to be validated is encrypted, specify the SignatureValidationOptions.DecryptionPassword property to decrypt the document. Otherwise, the Result property returns PackageSignatureValidationResult.PackageOpenFailed.

If the PackageSignatureValidation.Result property returns Invalid or PartiallyValid, check the PackageSignatureValidation.Items property to obtain a list of items with detailed validation information. The number of SignatureValidationInfo objects in the list is equal to the number of signatures.

The table below lists API used to obtain information:

Property	Description
SignatureValidationInfo.PassedChecks	Returns verification types the signature passed.
SignatureValidationInfo.PassedCheckDetails	Obtains information about passed verifications.
SignatureValidationInfo.FailedChecks	Returns verification types the signature did not pass.
SignatureValidationInfo.FailedCheckDetails	Retrieves information about failed verifications.
SignatureValidationInfo.CheckDetails	Gets information about all verifications.

The code sample below analyzes the validation result and shows information in the console:

C#

private static void AnalyzeValidationResult(PackageSignatureValidation signatureValidation)
{
    string validationMessage = signatureValidation.ResultMessage;

    //Check validation result and show information in the console:
    switch (signatureValidation.Result)
    {
        case PackageSignatureValidationResult.Valid:
            Console.WriteLine(validationMessage); Console.ReadKey();
            Process.Start(output);
            break;

        case PackageSignatureValidationResult.SignaturesNotFound:
            Console.WriteLine(validationMessage);
            break;

        case PackageSignatureValidationResult.Invalid:
        case PackageSignatureValidationResult.PartiallyValid:
            var failedCheckDetails = signatureValidation.Items[0].FailedCheckDetails;
            Console.WriteLine(validationMessage);
            int i = 1;
            foreach (SignatureCheckResult checkResult in failedCheckDetails)
            {
                Console.WriteLine(String.Format("Validation details {0}: \r\n" +
                    "{1} failed, Info: {2} \r\n", i, checkResult.CheckType, checkResult.Info));
                i++;
            }
            Console.ReadKey();
            break;
    }
}

VB.NET

Private Shared Sub AnalyzeValidationResult(ByVal signatureValidation As PackageSignatureValidation)
  Dim validationMessage As String = signatureValidation.ResultMessage

  'Check validation result and show information in the console:
  Select Case signatureValidation.Result
    Case PackageSignatureValidationResult.Valid
      Console.WriteLine(validationMessage)
      Console.ReadKey()
      Process.Start(output)

    Case PackageSignatureValidationResult.SignaturesNotFound
      Console.WriteLine(validationMessage)

    Case PackageSignatureValidationResult.Invalid, PackageSignatureValidationResult.PartiallyValid
      Dim failedCheckDetails = signatureValidation.Items(0).FailedCheckDetails
      Console.WriteLine(validationMessage)
      Dim i As Integer = 1
      For Each checkResult As SignatureCheckResult In failedCheckDetails
        Console.WriteLine(String.Format("Validation details {0}: " & ControlChars.CrLf & "{1} failed, Info: {2} " & ControlChars.CrLf, i, checkResult.CheckType, checkResult.Info))
        i += 1
      Next checkResult
      Console.ReadKey()
  End Select
End Sub