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jimmysofat6864 OP t1_j6h1txm wrote

Reply to comment by cache_bag in ELI5: Why are contactless payment methods faster than inserting the chip? by jimmysofat6864

That’s odd because sometimes I can be using the chip and it takes about 8 seconds and when I do contactless it usually finishes in 3 seconds based on my experience.

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cache_bag t1_j6h494a wrote

We're talking about the same exact card, right? In that 3 seconds, the charge slip is already being printed out, whereas it takes 8 for the dipped chip?

I suspect the app on the terminal reading the EMV takes its sweet time to talk to the card since it knows the card is just there. Whereas with contactless, the an imperative to optimize the communication. TL;DR bad programming of the app.

Both should work more or less within the same time window. Or at least not take 5 frigging seconds longer.

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jimmysofat6864 OP t1_j6h96xn wrote

Yea I’m taking about exact same card. It takes longer for a receipt to print out via chip compared to using contactless or mobile payment.

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RusticGroundSloth t1_j6jmh5c wrote

I've got 2 semi-educated guesses on why this is.

  1. Using the chip there's a decryption process to get the data off the chip. The terminals in use aren't exactly using high-end processors, so the decryption could take a bit longer. With the contactless payment it's just exchanging a small amount of data without the encrypt/decrypt taking up time.

  2. The time it takes to contact the payment processor and get authorization. I've noticed a significant difference between a Wal-Mart and a Smith's (Kroger) in my town. Both of them don't take contactless payments so this is with the chip. The Wal-Mart takes ~10 seconds to return an authorization, but the Smith's takes about 3 seconds. Same card, even looks like the same PIN-pads on the self-checkouts. Could be faster network/Internet speeds at the store, could be differences in how they process the payments (I wouldn't be surprised if Walmart has some centralized setup to handle that rather than each store "calling" the credit card service)...hard to say, but there are a lot of variables beyond just chip vs NFC.

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