Private Declare Function CryptAcquireContext Lib "advapi32.dll" Alias "CryptAcquireContextA" ( _
    phProv As Long, _
    ByVal pszContainer As String, _
    ByVal pszProvider As String, _
    ByVal dwProvType As Long, _
    ByVal dwFlags As Long) As Long

 [DllImport("advapi32.dll")]
    private int CryptAcquireContext(int? phProv, string pszContainer, string pszProvider, int? dwProvType, int? dwFlags) : 
     {
      не могу понять как обратиться к CryptAcquireContextA
     }