(SQL Server) DKIM Signature using Windows Current User Certificate Store

This is a Windows-specific example to load a certificate from the Current User (registry-based) certificate store, and then use the certificate's associated private key for a DKIM signature.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @cert int
    -- Use "Chilkat_9_5_0.Cert" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Cert', @cert OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- The LoadByCommonName method searches the Windows Local Machine and Current User 
    -- registry-based certificate stores for a certificate having the common name specified. 
    -- If found, the certificate is loaded and ready for use.
    DECLARE @success int
    EXEC sp_OAMethod @cert, 'LoadByCommonName', @success OUT, 'My Certificate ABC'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    -- The certificate must have an associated private key installed, and it must be a
    -- private key that has been marked "exportable" when it was originally installed.
    EXEC sp_OAMethod @cert, 'HasPrivateKey', @iTmp0 OUT
    IF Not @iTmp0
      BEGIN

        PRINT 'This certificate does not have a private key available.'
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    DECLARE @privKey int

    EXEC sp_OAMethod @cert, 'ExportPrivateKey', @privKey OUT
    EXEC sp_OAGetProperty @cert, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    DECLARE @dkim int
    -- Use "Chilkat_9_5_0.Dkim" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Dkim', @dkim OUT

    -- Load the private key into the DKIM object:
    EXEC sp_OAMethod @privKey, 'GetPkcs8Pem', @sTmp0 OUT
    EXEC sp_OAMethod @dkim, 'LoadDkimPk', @success OUT, @sTmp0, ''
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @dkim, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @cert
        EXEC @hr = sp_OADestroy @dkim
        RETURN
      END

    -- The private key has been loaded into the DKIM object.  See the other DKIM
    -- examples for guidance on how to create a DKIM signature...

    EXEC @hr = sp_OADestroy @privKey


    EXEC @hr = sp_OADestroy @cert
    EXEC @hr = sp_OADestroy @dkim


END
GO