NFC Access Reader Using Volatile Key Transfer for Fast Entry
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Solution Overview
Problem
Existing NFC-based access control systems require users to wait for seconds to read virtual keys from RFID tags, risk activating unintended device functions, and expose keys to unauthorized access due to delayed deletion.
Innovation Solution
An access control system using an NFC arrangement with a volatile memory and processing device that instantly transfers virtual keys from an NFC device to the processing device, eliminating the need for NFC card emulation and ensuring secure, rapid access decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a local RFID tag is used to store the virtual key, then the key can be written and read, but the user must wait several seconds for the reader to read the key before access can be granted
Solution Approach 1:
The patent extracts the virtual key data from the RFID tag memory and transfers it directly to the access control reader's processing unit, bypassing the need to read from the tag's memory storage. This extraction approach eliminates the memory read delay while maintaining the security of temporary key availability.
Solution Approach 2:
The patent introduces an intermediary mechanism where the NFC device acts as a mediator to transfer the virtual key directly to the access control system without requiring the RFID tag memory to be read. This intermediary transfer path significantly reduces the time required for access control decisions.
2Ease of operation
If the NFC device remains in the RFID reader's field, then the virtual key can be written to the tag, but other functionality in the NFC device may be accidentally activated
Solution Approach 1:
The patent extracts the virtual key writing process from the traditional RFID tag memory storage approach and implements it through direct NFC communication. This allows the key to be written to a temporary buffer without requiring the NFC device to remain in the reader's electromagnetic field, thereby preventing accidental activation of other NFC functionalities.
Solution Approach 2:
The patent performs the virtual key writing action preliminarily through NFC communication before the NFC device needs to be removed from the reader field. By completing the key writing in advance through a different communication mode, the system prevents unintended activations while maintaining ease of operation.
3Reliability
If the virtual key remains in the RFID tag memory, then it can be read by the access control system, but it is vulnerable to being read by other NFC devices before deletion
Solution Approach 1:
The patent extracts the virtual key from persistent RFID tag memory and holds it in a temporary buffer during the access control process. This extraction from permanent storage eliminates the vulnerability window where unauthorized devices could read the key, while still allowing the legitimate access control system to retrieve it for authentication.
Solution Approach 2:
The patent implements a discard-and-recover mechanism where the virtual key is temporarily held in memory during the access control transaction and then automatically discarded after use. This ensures the key is never left in a vulnerable state in persistent storage, as it is continuously overwritten or deleted after each authentication event.
4Adaptability or versatility
If NFC card emulation mode is used, then smartphones can function as virtual keys, but some manufacturers have blocked external access to this mode
Solution Approach 1:
The patent implements a universal access control system that uses NFC read/write mode, which is available on all NFC-enabled smartphones regardless of manufacturer restrictions on card emulation. This multi-functional approach allows the system to work with any smartphone that has NFC capability, achieving broad compatibility without requiring card emulation mode.
Solution Approach 2:
The patent changes the operational parameter of the NFC interface from card emulation mode to read/write mode. This parameter change bypasses manufacturer restrictions on card emulation while maintaining full functionality for virtual key operations, thereby achieving smartphone compatibility without increasing system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables instant access control decisions and secure key handling without relying on NFC card emulation, reducing user wait time and minimizing key exposure risks.
Implementation Method 1
NFC technology, that generally follows the same RFID standards as the RFID communication that is used for physical access systems
Implementation Method 2
the memory of the NFC arrangement is a volatile memory, which is physically connected to the at least one processing device
Implementation Method 3
allow a virtual key from the NFC device to be written to the memory as an NDEF message, using the NFC read/write mode in the NFC device
Data Source
AI summary
A system includes an access control arrangement, an NFC arrangement, an NFC antenna, a memory, and processing device. The NFC arrangement is arranged to: activate an NFC read/write mode in an NFC device with an active NFC field, by the NFC device sensing the NFC antenna in its NFC field; allow a virtual key from the NFC device to be written to the memory as an NDEF message, using the NFC read/write mode in the NFC device; immediately transfer the NDEF message from the memory to the at least one processing device; and delete the NDEF message from the memory as soon as it has been transferred to the processing device. The processing device is arranged to: receive the NDEF message representing the virtual key from the memory; compare the received virtual key to pre-stored valid virtual keys; and based on said comparison, take an access control decision, to grant or deny access.