Clerk: Here is your money. What is your passport number?

职员：给您钱。您的护照号码是多少？

youdao

Very well. Here is an exchange memo. Please fill in your name, passport number, your nationality, and the amount you intend to change.

好的。这是兑换水单。请填上您的名字，护照号，您的国籍及所要兑换的钱款金额。

youdao

If you will. please fill out this card. Please write your name and home address here. This is where you put your passport number.

如果您愿意的话，请填写这张卡。请在这里写上您的姓名，家庭住址。这里填写您的护照号码。

youdao

For Passport this is an important number because Stouffer trades as if stock exchanges were going out of style. (Portfolio turnover: 700% a year.) You're not going to have any luck getting this stat from the folks manning the toll-free number.

FORBES: Peekaboo!

"The difference with biometrics and the reason it presents a substantial threat is that if your passport is stolen, the government can reissue you a new passport number and you can move on with your life, " he tells CNN.

CNN: Fully biometric airports becoming a reality

The key turns out to be predictable given that it is sequentially issued and constructed from the passport expiry date, birth date, passport number, and checksum.

ENGADGET: Dutch RFID e-passport cracked -- US next?