Private Function SignBytes(ByVal SrcBytes As Byte(), Certificate As X509Certificate2) As Byte()
Dim Result As Byte() = Nothing
If SrcBytes IsNot Nothing AndAlso SrcBytes.Length > 0 AndAlso Certificate IsNot Nothing Then
Try
Dim contentInfo As New ContentInfo(SrcBytes)
Dim signedCms As New SignedCms(contentInfo, True)
Dim cmsSigner As New CmsSigner(Certificate)
cmsSigner.IncludeOption = X509IncludeOption.EndCertOnly
cmsSigner.SignedAttributes.Add(New Pkcs9SigningTime)
signedCms.ComputeSignature(cmsSigner, False)
Result = signedCms.Encode()
Catch ex As Exception
Throw New Exception(ex.Message)
Result = Nothing
End Try
End If
Return Result
End Function

Public Function SignBytesAdd(ByVal SignedData As Byte(), ByVal SrcBytes As Byte(), ByVal Certificate As X509Certificate2) As Byte()
Dim Result As Byte() = Nothing
If SignedData IsNot Nothing AndAlso SignedData.Length > 0 AndAlso SrcBytes IsNot Nothing AndAlso SrcBytes.Length > 0 AndAlso Certificate IsNot Nothing Then
Try
Dim contentInfo As New ContentInfo(SrcBytes)
Dim SignedCms As New SignedCms(contentInfo, True)
SignedCms.Decode(SignedData)
Dim CmsSigner As New CmsSigner(Certificate)
cmsSigner.IncludeOption = X509IncludeOption.EndCertOnly
CmsSigner.SignedAttributes.Add(New Pkcs9SigningTime)
SignedCms.ComputeSignature(CmsSigner, False)
Result = SignedCms.Encode()
Catch ex As Exception
Throw New Exception(ex.Message)
Result = Nothing
End Try
End If
Return Result
End Function

Public Function CertificateRemove(ByVal SignData As Byte(), CertCol As X509Certificate2Collection) As Byte()
Try
' Декодируем сообщение
Dim signedCms As new SignedCms
signedCms.Decode(SignData)
For Each si As SignerInfo In signedCms.SignerInfos
If CertCol.Contains(si.Certificate) Then signedCms.RemoveSignature(si)
Next
Return signedCms.Encode()

Catch ex As Exception
Throw New Exception(ex.Message)
Return Nothing
End Try
End Function