PackageDigitalSignatureManager.IsSigned Property

Definition

Namespace:

System.IO.Packaging

Assembly:

WindowsBase.dll

Gets a value that indicates whether the package contains any signatures.

public:
 property bool IsSigned { bool get(); };

public bool IsSigned { get; }

member this.IsSigned : bool

Public ReadOnly Property IsSigned As Boolean

Property Value

Boolean

true if the package contains signatures; otherwise, false.

Examples

The following example shows how to use the IsSigned property to determine if a package contains digital signatures. For the complete sample, see Creating a Package with a Digital Signature Sample.

// ------------------------ ValidateSignatures ------------------------
/// <summary>
///   Validates all the digital signatures of a given package.</summary>
/// <param name="package">
///   The package for validating digital signatures.</param>
/// <returns>
///   true if all digital signatures are valid; otherwise false if the
///   package is unsigned or any of the signatures are invalid.</returns>
private static bool ValidateSignatures(Package package)
{
    if (package == null)
        throw new ArgumentNullException("ValidateSignatures(package)");

    // Create a PackageDigitalSignatureManager for the given Package.
    PackageDigitalSignatureManager dsm =
        new PackageDigitalSignatureManager(package);

    // Check to see if the package contains any signatures.
    if (!dsm.IsSigned)
        return false;   // The package is not signed.

    // Verify that all signatures are valid.
    VerifyResult result = dsm.VerifySignatures(false);
    if (result != VerifyResult.Success)
        return false;   // One or more digital signatures are invalid.

    // else if (result == VerifyResult.Success)
    return true;        // All signatures are valid.
}// end:ValidateSignatures()

' ------------------------ ValidateSignatures ------------------------
''' <summary>
''' Validates all the digital signatures of a given package.</summary>
''' <param name="package">
''' The package for validating digital signatures.</param>
''' <returns>
''' true if all digital signatures are valid; otherwise false if the
''' package is unsigned or any of the signatures are invalid.</returns>
Private Shared Function ValidateSignatures(ByVal package As Package) As Boolean
    If package Is Nothing Then
        Throw New ArgumentNullException("ValidateSignatures(package)")
    End If

    ' Create a PackageDigitalSignatureManager for the given Package.
    Dim dsm As New PackageDigitalSignatureManager(package)

    ' Check to see if the package contains any signatures.
    If Not dsm.IsSigned Then
        Return False
    End If
    ' The package is not signed.
    ' Verify that all signatures are valid.
    Dim result As VerifyResult = dsm.VerifySignatures(False)
    If result <> VerifyResult.Success Then
        Return False
    End If
    ' One or more digital signatures are invalid.
    ' else if (result == VerifyResult.Success)
    ' All signatures are valid.
    Return True
End Function
' end:ValidateSignatures()

Remarks

The IsSigned property does not perform signature validations. If signatures are present and IsSigned is true, one or more of the signatures might not be valid. Call VerifySignatures to confirm that the signatures are valid and have not changed.

See also

• VerifySignatures(Boolean)
• Open Packaging Conventions (OPC) Specification