Communication with high-security cards, e.g. DESFire, which uses cryptographic protocols (DES, 3DES, AES), relies on cryptographic algorithms. This means that there are a lot of intensive calculations and repetitions.
In case this is done in a library or software, the communication channel remains the security weak point. Otherwise, if this takes place in hardware, the entire cryptography is secure.
Given the above security weaknesses, Digital Logic has applied a special method of storing and processing keys within the hardware. All calculations, key exchange, key storage, and more are performed in the hardware (reader). This means that secret keys do not come out of the device when the reader and host communicate. For this feature, Digital Logic uses the AES128 crypto algorithm for DESFire cards/tags. The keys are securely stored in the reader and cannot be compromised. It was a logical solution because AES128 is quite fast and efficient compared to DES and 3DES which still perform processes externally by the software.