The popular protocol of the Secure Electronic Transaction(SET)discussed by this paper has the flaws of the goods atomic transactions and certified delivery atomic in transacting digital goods.

文章对现在流行的安全电子交易SET标准进行分析，指出SET协议存在不满足数字商品交易的原子性以及确认发送原子性等缺陷。

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Now that particular part is true: weirdly, VAT on digital goods is paid at point of dispatch, not delivery.

FORBES: Facebook, Apple, Google, Amazon: Why Cannot France Understand That They Already Do Pay Taxes?