Contactless payment, like the Octopus I'm used to in HK or any ISO/IEC 14443 technology (Paywave, Paypass, NFC) are all public key/private key encrypted.

I'm not sure the technology is as strong, but the authentication protocols are similar to those as if you've used a chip. The only difference is you don't phsycially connect the chip to the reader, but depend on radio technologies to do the same.

I think your "mag reader" analogy will be like my old-fashioned remove garage door opener that is hard coded to a certain combination? That can easily be compromised by capturing the frequency/combination, akin to skimming a magstrip card. That would not work on contactless payment.

http://en.wikipedia.org/wiki/Octopus_card#Security
http://en.wikipedia.org/wiki/ISO/IEC_14443
http://en.wikipedia.org/wiki/PayPass#PayPass

My understanding is that using a magnetic reader you can easily copy a credit card issued in US, because what the reader reads is the real CC number and other permanent information, not some key codes that CPU-embedded cards provide.

And, there are numerous discussion about contactless CC being prone to RF readers from afar, and there are even wallets with the feature of blocking radio signals. That don't come without a reason, right?

So, my guess is that contactless CC without EMV is still different from contactless CC with EMV?

Can you get a get a contactless CC without EMV (or similar technology)?

The concern of course is that you can get a rogue portable reader that can obtain an online authentication whilst being pressed against our clothes.

I find the possibility a bit far fetched tho. Currently I have to press my Paywave card pretty much against the side a reader for it to read. My Octopus can be read under one layer of wallet skin but normally that skin is against my thigh.

using unionpay cards in alaska
 

Alaska is conspicuously absent from US section. Anybody have any insight?

just read some wiki, looks like any contactless credit card, even it doesn't have EMV chip, has at least a chip for the contactless transmission.

I've never received any contactless cards from Chase, and really don't see a lot of that in the US. Asia is pretty popular with that, and I saw lots of Aussies using contactless (making those markets easier for Apple Pay because of the abundance of contactless readers at merchants, right?).

Sydney transit put in Paywave/Paypass before introducing Opal a year or so ago.

Plus, wouldn't some people rather immediately notice that someone has charged their CC? (by SMS information) - and most people would notice some "weird" charges within a few days, and complain. Then, as the "robber" would obviously need to be registred somewhere to get the money from MC/Visa, it should be rather easy to pin him down, wouldn't it?

Yuropflyer: in my very limited experience I don't find paywave transactions trigger SMSes...they just aren't big enough to justify notification

However you're right that a rogue thief will have their merchant accounts cut, if chargebacks stack up.

SMS thing is more like a Chinese thing? Even though SMS from merchants are free in the US, I've never seen any bank in the US providing instant SMS notification.

Chase has instant notification through pushing, and it's like receiving a push email. It is very instant and it is very helpful to me. I can tell how many charges are there before the merchants give me the receipts.

In Europe, CC anti-fraud SMS is very popular. That one has to pay to receive a SMS is imho something unique to the US, never heard about that anywhere else.

For the curious, my Discover-in-Japan transaction has posted with a correct rate, without that 11% fee.

Not sure if universal but probably merchants that have the Discover signage on the door are really only passing the transaction through the JCB Group, even though the Discover signage is often one half of a sticker shared with Diners Club International. (As far as I know Discover does not work over the Diners Club International acceptance network in Japan?)

FYI - The Peninsula in Beijing tried to DCC me. I asked to be charged in local currency and they immediately fixed it.

It's good to know the rate posted correctly. ^ I'm vacillating on whether or not to apply for Discover card just for convenient use in China to avoid DCC.

I'm glad you were able to get out of DCC. Larger hotels in the major cities seem to be able to disable DCC, but I would say China is by far the worst offender when it comes to DCC.

You'd be surprised how good it works in China, provided you can convince them to swipe it. I got the beach design and often they are confused as to what it is. lol. Even trying to convince them in Chinese isn't easy. Best print out the little card on the discover website that explains it for you.

Plus, the discover isn't the worst card to have. The 5% rotating CB is actually quite good.

Make sure to keep all the receipts, many places will print the FULL acct number on the the receipt. Don't know why, but they do.

Someone around here was selling UnionPay logo stickers to place on the Discover card. I don't speak more than some basic Mandarin phrases, so trying to convey that there is an agreement between UnionPay and Discover (or trying to get out of DCC) might be difficult. :D