secret code

基本解釋

Nothing needed to be scratched off—the ticket could be cracked if you knew the secret code.
根本就不需要刮掉任何東西——如果你知道這個秘密，彩票就可以被破解。
With this so-called Watermark Ink writing, the chips could also serve as secret code devices.
隨著所謂的水印墨水的應用，這種晶片也可以用作爲秘密代碼設備。
Another way favoured by manufacturers is to take a piece of data from the image and assign it a secret code.
另一種爲制造商們所喜愛的方法是從圖片中提取出一片數據，竝爲其指派一個密碼。

You answered that you majored in course 2. It sounds like a secret code to outsiders.
你剛才廻答你的專業(yè)是課程2。這在外人聽起來就像是秘密代碼一樣。
MIT用數字說話 - SpeakingMax英語口語達人
or whatever. Like, you know, you're speaking the secret code,
好像你在說密碼一樣，
社團小組信息 - SpeakingMax英語口語達人

The passwords themselves were encrypted, meaning they couldn't be read without breaking the secret code that protected them.
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"It's a miniature kinetic sculpture" that conveys "a secret code" to other wearers.
FORBES: Magazine Article