SQL Server

Remove All S/MIME Security Layers (UnwrapSecurity)

Demonstrates the Chilkat Mime.UnwrapSecurity method, which removes supported S/MIME security layers and restores the underlying MIME content. It takes no arguments and handles both layer orders: signed-then-encrypted and encrypted-then-signed.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: A message can be both signed and encrypted, in either order, producing nested S/MIME wrappers. UnwrapSecurity peels them all off in one call — verifying signatures and decrypting as it goes — so you do not have to detect the layering and call Verify and Decrypt in the right sequence yourself. Decryption still requires the recipient's certificate and private key to be configured.

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--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  Demonstrates the Mime.UnwrapSecurity method, which removes supported S/MIME security layers and
    --  restores the underlying MIME content.  It takes no arguments and handles both layer orders
    --  (signed-then-encrypted and encrypted-then-signed).

    DECLARE @mime int
    EXEC @hr = sp_OACreate 'Chilkat.Mime', @mime OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OAMethod @mime, 'LoadMimeFile', @success OUT, 'qa_data/secured.eml'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @mime, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @mime
        RETURN
      END

    --  A single call peels off the signature and/or encryption layers.  (Decryption requires the
    --  appropriate certificate/private key to be configured first.)
    EXEC sp_OAMethod @mime, 'UnwrapSecurity', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @mime, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @mime
        RETURN
      END


    EXEC sp_OAGetProperty @mime, 'ContentType', @sTmp0 OUT
    PRINT 'Security layers removed. Content-Type is now: ' + @sTmp0

    EXEC @hr = sp_OADestroy @mime


END
GO