Card types and how to get the head around?

[Cieska]

Hi boys and maybe some girls,
In the past, when all the bits has been designed and given on the plate as needed I didn't have this problem. But lately, when I was thrown in to the ongoing random "mess", I realise that, I need to get my head around about understanding card types, bits and ideally how quickly figure out what card type is and what should work with what. When questions comes with bit and types. Then including enrolment card readers, that is possible to be programmed to read different formats and so on.
Ideally would be, to find some on-line training or maybe guides that could put me on the right way. Any techniques to figure out card types? Any device to buy or?
So long story short, I need some nitty-gritty guidance on card types.
No **** please.
Cheers for the beers.

[james.wilson]

What are you trying to do? 

[Cieska]

Hi,
I know it's my old topic, but I have come back to it.

 

The complication is to understand Card formats and how to read the data. At the moment for example:

• I have a Mifare Classic 4K card
• the ACS system by default reads the first 32bit which is the Card Serial Numer (CSN)
  • The system is CEMsys AC2000
• I know that I need to read different numbers, which are 8-digit number encoded in Sector-1 Block-2.
• To read CSN in the card definition setting field of the AC2000
  • Start position - 1
    • My question is why is this not start from position - 0 ? As computers read from zero first? As otherwise then all pern doesn't match when counting bits? Or I'm wrong here?
  • Field length - 32
    • this is where I match my understanding against the CSN as I can read and match the first 32bits (4bytes) or hex value, in the screenshot line 92 of my text editor where I have selected the value.
• So, if the block length is 128bit (per line), then my interesting data starts at the 6th line which is per block number [05] (text editor line 100) as it starts counting blocks from [00] in the sector [00]. This should mean that it should start read my interesting data from 641bit and the Field length should be 24bits (as 8 digit number fits in 3bytes  https://www.rapidtables.com/convert/number/decimal-to-hex.html )
  • another question here is - if the 8-digit number is encoded in hex or it's just the same number but in numbers only? In other words to say, how the read data is interpreted? Or if the reader reads the CSN number and displays hext then my number also, should be displayed as simple as this?
• We are talking about reading unencrypted data, as I was told I should read this dara simply when scanning the card.

 

So I have many unknowns in my head, which is why it is totally confusing. I need some guidance or tips. or anything. 

 

 

The

[sixwheeledbeast]

I suppose these are using proprietary Crypto1 format?

If so maybe look at the documentation from the people that RE'd it?

[Cieska]

On 26/05/2024 at 16:15, sixwheeledbeast said:

I suppose these are using proprietary Crypto1 format?

If so maybe look at the documentation from the people that RE'd it?

I was told that I could read the number simply when reading the card. So I guess it is not encrypted. Otherwise, I won't be fighting here. The dashes in Sectors 1 and 2 are because I would think I read this card with mobile NFC? or should I consider something not good here? Well, I'm first time using this mobile app to read the card. 

Edited May 27 by Cieska

[Cieska]

At the same time, where would I get such training or knowledge related to card technologies in real life?

[james.wilson]

I dont know of any training courses for that

[MrHappy]

Way too deep for my understanding,

 

@Cieska if you have the time & talent to work out what does what & how it does it...

 

Write an idiots guide for me

[bm99]

Lol this would be wicked if it was dumbed down enough for me haha

 

On thr same token however is there not a thread about the various prox tags for alarm systems?