11

Why is it that common smartcards like the SLE5528 are almost always limited to <16K of available memory, and a very slow 8 bit processor? What is the limiting factor that makes it technologically/economically infeasible to raise these limits? It's the extra price caused by the security features that drive up the price. Technically you can't compare the ...


6

That's the way smartcards work. If you want a USB stick, you know where to find it. Smartcards are designed for security. They're designed to be tamper resistant. They're designed to store secrets and to commit suicide rather than give up their secrets. You can't (with reasonable effort, barring implementation flaws) extract the data from it, or clone it. ...


4

It looks like nothing special is done. See xray and other teardown. I would say that the localised bending is probably small enough, and limited by the nearby inflexible chip, that this turns out not to be a problem. The cards do have a limited life of a few years, and although they're flexible people don't actually routinely bend them that much - the ...


3

Electronically: Produce a series tuned circuit tuned resonant at the frequency of the card system - this acts as a "suck out trap. This could be conductive ink printed on paper or similar and stuck on the card surface. The trap need not occupy the whole card area but mechanically overlapping part of the loop conductors may help. I have not investigated the ...


3

The original answer is correct, but it lacks details. ISO14443 is a contactless protocol (cards with an antenna embedded). It specifies only the lower-level of the communication protocol (what happens on the physical / link layer), but it does not specify the commands available at the upper level. ISO7816 is a specification that was initially written for ...


3

First, everything is specified in ISO7816-3. You should really read it (I won't provide any links because the standard is not free, but you can still easily find it on the web). Now, regarding your specific questions: Yes, you need to generate the clock that will be applied to the CLK pin. This clock does not need to be accurate. There is, however, a ...


3

mechanically, you're nearly right – think of it as top-bottom: Place the contact pads upside down on a plane surface. Take a bit of (relatively elastic) glue and fix the die onto the center of the contact pad's back. Then use an automatic bonding machine to weld small wires from contact pads to die, with a bit of a "curve". That way, your die gets a bit of ...


3

Rise time is determined by how much current flows into the capacitor. T = CV/I, so time increases when current is reduced. Anything that limits the charging current or bypasses it away from the capacitor will increase the rise time. To calculate the rise time you need to know the internal resistance and current limit of your power supply, and how much ...


3

It's a SN/CD54/74HC02 quad NOR. The "36A2DKK" is a lot code. source


3

Elm Electronics makes a series of chips for interfacing a micro to the obdII port. Doing this yourself or figuring out the protocol is a large project. Alternately, you might consider tying into the crankcase sensor, or other sensor available on that particular car. I assume this is diesel, so you can't tie into the fuel injection or ignition system?


2

The "antenna" used in an RFID tag is a coil of wire (an inductor), and it interacts with only the magnetic portion of the RF field emitted by the reader. It may also be part of a tuned circuit that helps the tag extract power from the signal. Therefore, any coil that has the same value of inductance, regardless of its geometry, will work correctly with the ...


2

Without a link to the ring related page it's hard to be very specific BUT There is much rubbish and many false claims published on the internet.This has a good chance of being less veracious than may appear. The system may still function but with reduced range. It is exceedingly unlikely that it will work anything like as well as it did in its original ...


2

1) Encrypt the traffic. This is actually quite a pain, as you either need to authenticate the card and reader to one another or use a pre-shared key that you keep very careful watch over. You're best off buying in a solution here; SIM cards seem to have been very successful, and MIFARE contactless payment cards I know offer a DES-based secure system. 2) ...


2

Squeezing that sort of functionality into a credit card form factor is not easy. You can't use regular circuit board fabrication techniques because the end product needs to be thin enough to fit into a card reader. It probably costs hundreds of thousands to millions in NREs to make a device like that as it likely requires one or more custom ICs that need ...


2

Yes. They are all part of the same association. Yes. The PayPass, et. al. cards are embedded with an RFID inlay that meets ISO 14443-A and ISO 14443-B standards and operates at 13.56MHz (same as cell phones)[1]. Just because they have the physical layer, however, does not mean that this will be supported for cell phones due to the security risk it ...


2

The module is connected to the antenna using conductive adhesive. At the backside of the module there are two pads that are glued to the antenna. For this reason the antenna needs some pads as well or a meander-shaped region that serves the same purpose. A more detailed discussion can be found here: http://arxiv.org/pdf/1507.06427.pdf.


2

You don't need to change the clock rate that high (and it certainly wouldn't be supported by the card). You simply need to adjust Fi and Di, indeed. Here is an extract from the ISO7816-3 spec: To reach ~115200 bauds, typically, you'll choose Fi=512 (F=9) and Di=32 (D=5). This, with the same clock of 3.58MHz, will give 111875 bauds. For exactly 115200 bauds,...


2

There are basically two ways to embed an antenna in a smart card: Either make the antenna out of enamelled wire and sandwich it between two sheets of plastic. Then, as pjc50 said, there is nothing really particular to take care of at the crossing. But this solution makes it a bit difficult to bond the antenna to the chip. There needs to be some intermediate ...


2

First some background on sims. The contact arrangements of Sim cards are based on ISO smart-cards. Originally they were the same size as credit cards (and the outer plastic SIM cards are shipped in still is) but quickly space constraints resulted in a reduced size version technically called "mini sim" being the dominant size in nearly every phone. Mini sim ...


1

As mentioned earlier, STM32CubeMX creates a project directory and generates all the files you need to set up the peripheral pins and clocks. In addition, the Cube generates files for the HAL (Hardware Access Layer). In terms of using the TX (which I am thinking you mean UART?), you could use the HAL functions to use the UART. [Conversely, you could ...


1

I believe contactless payment cards usually don't 'give out' the card number, CSC, expiry etc... Otherwise, that wouldn't make them much more secure than magnetic strips. AFAIK, contactless bank cards generally receive a cryptographic challenge from the bank, sign it and return the result to prove they are a real card. I suspect what happened was that the ...


1

Here's a link that explain quite well what the pinout is. http://pinoutsguide.com/Memory/SmartCardIso_pinout.shtml And by experience the IC inside these kind of cards are simply a little DIE package right under the connector Here's is a picture of the actual structure of a smart card And here is a list of what type of cards you can find Smart Card Types


1

SLE4442 is not the same as a SIM and doesn't have any crypto capabilities, so you can't get the card to sign a challenge. All you can use is its security code system, where you get 3 tries to enter a code or get locked out of the card.


1

Probably for mechanical reasons. It is the feature nearest the edge, so it is more likely to get bent or cut. Making it wider makes it stronger so it is less likely to get damaged.


1

It looks like the reset functionality of that pin is enabled by the positive edge of a pulse and the power down is enabled by pulling it LOW, so if you have the pin tied to HIGH, there won't be positive edge of a pulse to reset the chip, during normal operation, and power down won't happen cause it isn't low.


1

Answering because I get traffic from this question. Overcooking an answer to this issue is unwarranted. Designing an electronic something to make the modification invisible seems also overkill (even though I love making electronic somethings). IMHO, the minimum viable solution consists of what is within hands-reach when I'm opening my letters. Being, a ...


1

There is certainly no need to punch 3mm holes through the card as in the image you referenced. All you need to do is cut one of the antenna coil wires and the RFID function is dead. What this looks like after the fact depends on your tools and skills. You will first need to know where the wires are. You can x-ray a card but that sounds rather expensive ...


1

If its important enough to worry about, simply sssume the data will be hacked, and encrypt it.


Only top voted, non community-wiki answers of a minimum length are eligible