After a few long moments I figured out that I needed to slide my room key through a mostly hidden card reader to the side of the control panel.

用了很长时间我才弄明白原来我需要把自己的房卡在电梯控制板旁边的一个隐蔽的读卡器里刷一下。

youdao

The "Hidden" card features a keypad and black-and-white display for six of the digits in the card's unique number.

另外一种“隐形卡”的特色是有一个小键盘，以及显示卡号缺损数字的六位黑白显示器。

youdao

Since the security requirement dictates that the means of payment (such as credit card or bank check) must be hidden from unauthorized viewers, encrypting the payment element pays off.

由于安全性要求规定必须对未授权的查看者保密支付方式(诸如信用卡或银行支票)，对Payment元素加密就做到了这一点。

youdao

No one knows until the end of the game whose hidden card is the winner.

VOA: special.2009.11.22

But they also have a right not to get ripped off by the sudden rate hikes, unfair penalties and hidden fees that have become all too common in our credit card industry,"

VOA: standard.2009.05.09

She likened the fees to a hidden tax on card holders.

NPR: Consumer Groups Seek Cap on Credit Card Fees

Once tokenized and hidden, any given card product is far more vulnerable to being displaced, as the issuers have already learned from PayPal.

FORBES: Tokenization And The Collapse Of The Credit Card Payment Model

We cracked down on unscrupulous lenders and credit card companies that charge hidden fees.

WHITEHOUSE: The White House