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V22.1
.NET Framework 4.5.2+

DocumentSigner.Validate(Stream, SignatureValidationOptions) Method

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

Namespace: DevExpress.Office.DigitalSignatures

Assembly: DevExpress.Docs.v22.1.dll

Declaration

public PackageSignatureValidation Validate(
    Stream inputStream,
    SignatureValidationOptions options
)

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 property to exclude validation steps.

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);
}

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:

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;
    }
}
See Also