SecureSign() Method

Visual Basic (Declaration)
Visual Basic (Usage)
C#
Managed Extensions for C++
C++/CLI

Public Overloads Function SecureSign() As X509Certificate2Collection

Dim instance As MailMessage
Dim value As X509Certificate2Collection
 
value = instance.SecureSign()

public X509Certificate2Collection SecureSign()

public: X509Certificate2Collection* SecureSign();

public:
X509Certificate2Collection^ SecureSign();

Return Value

System.Security.Cryptography.X509Certificates.X509Certificate2Collection containing the certificates included within the signed message.

From is used to locate a signing certificate in the "MY" certificate store and X509IncludeOption.ExcludeRoot used. DigestAlgorithm.Sha256 is used for creating the message hash. A "detached" digital signature is created and included as an attachment.

Use SecureSign(X509Certificate2,X509IncludeOption,DigestAlgorithm,Boolean,Boolean) if additional control is desired.

This example demonstrates signing a message with the sender's digitial signature.

C#

using System.Security.Cryptography.X509Certificates;

private MailMessage getSignedMessage(MailMessage message)
{
    //Find the signing certificate in the "CurrentUser/My" certificate store
    //The following code results in the same signed message as "message.SecureSign();"
    X509Store myPersonalStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
    myPersonalStore.Open(OpenFlags.ReadOnly);
    foreach (X509Certificate2 certificate in myPersonalStore.Certificates)
    {
        if (certificate.Subject.Contains("E=" + message.From.ToString()))
        {
            //Sign the message
            message.SecureSign(certificate, X509IncludeOption.ExcludeRoot, DigestAlgorithm.Sha1, true, false);
            return message;
        }
    }
    return null;
}

Visual Basic

Imports System.Security.Cryptography.X509Certificates

Private Function getSignedMessage(ByVal message As MailMessage) As MailMessage
    'Find the signing certificate in the "CurrentUser/My" certificate store
    'The following code results in the same signed message as "message.SecureSign();"
    Dim myPersonalStore As New X509Store(StoreName.My, StoreLocation.CurrentUser)
    myPersonalStore.Open(OpenFlags.ReadOnly)
    For Each certificate As X509Certificate2 In myPersonalStore.Certificates
        If certificate.Subject.Contains("E=" & message.From.ToString()) Then
            'Sign the message
            message.SecureSign(certificate, X509IncludeOption.ExcludeRoot, DigestAlgorithm.Sha1, True, False)
            Return message
        End If
    Next certificate
    Return Nothing
End Function

Reference

MailMessage Class
MailMessage Members
Overload List