Table of Contents:
Introduction
What Is a CUID Card?
Is a CUID card an IC card?
Working Principle of CUID Cards
What Is a CUID Card Made of?
Core Features of CUID Card
Application Scenarios of CUID Card
Difference Between RFID Card and CUID Card
What Is the Difference Among UID, IC, ID, UUID, FUID, UFID and CUID Card?
Conclusion
Introduction
With the continuous development of the Internet of Things (IoT), intelligent security systems, and smart campus solutions, contactless smart cards have become increasingly crucial in areas such as identity authentication, access control, and payment. Among them, CUID cards have emerged as a common identification medium in many applications due to their stability and a certain level of security.
CUID cards are an optimized version of FUID cards. Unlike FUID cards, which allow only a one-time write operation to block 0—making it difficult to correct mistakes or reuse the card—CUID cards enable multiple modifications to block 0. The key difference between CUID cards and UID cards is that CUID cards do not have a backdoor; instead, they use conventional password verification to write to block 0. Other sectors operate the same way as standard M1 cards.
This article provides a systematic overview of CUID cards, including their operating principles, technical specifications, typical applications, advantages, and limitations, offering readers a clear understanding and a reference for selecting the right card.
What Is a CUID Card?
CUID stands for “Card Unique Identifier.” It refers to a type of contactless RFID card with a fixed, unique ID number. This unique identifier is programmed into the chip during manufacturing and is typically immutable and non-reproducible. This feature makes CUID cards widely used in access control systems, attendance tracking, public transportation cards, parking management, and other fields, effectively reducing common cloning risks and security vulnerabilities.
Compared to writable cards or fake UID cards that allow modification of the UID, CUID cards may not offer the advanced encryption capabilities of higher-end CPU cards or smart cards with password authentication mechanisms. However, they provide a stable and reliable solution in low- to medium-risk environments thanks to their good compatibility, moderate cost, and reasonable level of security.
Is a CUID card an IC card?
Strictly speaking, CUID is not a specific type of IC card but refers to the Card Unique Identifier — a unique identification code embedded within an IC card (smart card). It represents a feature or function of the card rather than a distinct card category.
What Is a CUID Card Made of?
A CUID card consists of two main components: the RFID chip and the antenna.
1. RFID Chip
Core Function: The RFID chip acts as the “brain” and “ID storage” of the CUID card. It stores the unique identifier (CUID) as well as other user data or security information.
Memory Structure: The chip typically contains a read-only memory area (where the unique ID is stored) and a read-write memory area (for user data, access permissions, etc.).
Processing Power: Some chips support encryption, enabling data security features like encryption, authentication, and anti-cloning to enhance system security.
Power Supply: Most contactless CUID cards don’t have a built-in battery. Instead, the chip gets its power through electromagnetic induction from the radio frequency signal emitted by the card reader.
2. Antenna
Function: The antenna receives the radio frequency signal from the card reader and transfers the energy to the RFID chip. It also transmits the chip’s response back to the reader.
Structure: The antenna usually consists of one or more loops of fine copper wire printed onto the card’s substrate, forming an electromagnetic coupling circuit.
Frequency: The antenna is designed for a specific operating frequency, commonly low frequency (125 kHz) or high frequency (13.56 MHz). The frequency affects read range and data transfer speed.
Working Principle of CUID Cards
The working principle of a CUID card is based on RFID (Radio Frequency Identification) technology. When the card is brought near a reader, the reader emits a radio frequency signal that powers the card and initiates communication. The card then sends its stored identifier to the reader, which uses that information to verify the cardholder's identity and trigger the appropriate action. Here's a breakdown of the general process:
1. Activation
When the reader emits an electromagnetic signal at a specific frequency, the card’s antenna picks it up and converts the energy into power to activate the chip.
2. Data Communication
Once powered, the chip reads its internally stored unique ID (CUID) and sends it back to the reader by modulating the radio signal. The communication follows standard protocols like ISO 14443 or ISO 15693 to ensure reliable data transmission.
3. Identification and Verification
The reader receives the CUID and passes it to the backend system, which checks it against a database to confirm the card’s identity and determine access rights or other permissions.
4. Security Measures
To prevent cloning or tampering, some CUID cards support encryption and even mutual authentication, ensuring both the card and reader verify each other’s legitimacy and that the data exchange remains secure.
Core Features of CUID Card
1. Efficiency: CUID cards offer fast recognition speed, enabling the rapid identification and management of a large number of objects.
2. Security: CUID cards use passwords and encryption algorithms to ensure the security of identification information.
3. Reliability: CUID cards have strong anti-interference capabilities and can function properly in complex environments.
4. Scalability: CUID cards can be integrated with other systems to achieve more complex management functions.
5. M1 Compatibility: CUID cards are replicas or compatible with MIFARE S50 (M1) cards, and are recognized by many devices that support M1 cards.
6. Standards Compliance: CUID cards typically operate at a frequency of 13.56 MHz (high frequency), conforming to the ISO 14443 Type A standard.
7. Rewritable Memory: The storage area on the card can be read and written repeatedly, with a long service life (typically over 100,000 cycles).
Application Scenarios of CUID Card
1. Access Control
CUID cards are widely used for access control in offices and buildings. They support employee identification, visitor management, and elevator access restrictions. They also help automate entry tracking and attendance recording.
2. Vehicle and Traffic Management
In parking lots and similar areas, CUID cards enable automatic vehicle identification and access control, improving efficiency and reducing the need for manual checks.
3. Membership and Commercial Systems
CUID cards are used in places like malls and gyms for member identification, tracking purchases, managing points, and applying discounts—enhancing customer service and business management.
4. Logistics and Warehouse Management
In logistics, CUID cards help track items in real time and manage deliveries. In warehouses, they simplify the process of checking goods in and out, speeding up inventory management.
5. Asset and Equipment Management
CUID cards can be attached to equipment to track location, usage, and maintenance. This improves asset visibility, supports maintenance planning, and enhances overall management.
Difference Between RFID Card and CUID Card
RFID cards (Radio Frequency Identification Cards) are electronic cards that use wireless radio frequency technology for identity recognition and information transmission. They are widely used in scenarios such as logistics, warehousing, supply chain management, library borrowing systems, and retail tracking. Their core advantage lies in contactless identification, enabling long-distance reading and batch scanning. However, the security of ordinary RFID cards is relatively low; some cards’ unique identification codes (UIDs) may be vulnerable to duplication, especially in low-cost tag cards. Additionally, RFID cards from different brands or batches may have duplicate UIDs, posing risks to the system’s ability to uniquely identify them.
CUID cards (Card Unique Identifier) are essentially customized RFID cards with unique serial numbers, designed specifically to address the issues of UID duplication and easy counterfeiting found in ordinary RFID cards. During the manufacturing process, a globally unique identifier that cannot be altered is written into the CUID card. These cards are typically used in conjunction with access control, security authentication, and other systems. For example, in scenarios requiring high security and permission verification—such as door access, elevator control, attendance management, membership authentication, and equipment asset tracking—CUID cards provide a more reliable identity recognition mechanism. Additionally, CUID cards often use high-frequency 13.56 MHz technology, are compatible with mainstream IC card readers, and possess strong anti-cloning capabilities.
What Is the Difference Among UID, IC, ID, UUID, FUID, UFID and CUID Card?
1. UID Card
Definition: A common duplicate card that can repeatedly overwrite all sectors.
Features: All sectors can be rewritten, suitable for copying ordinary IC cards.
Limitations: Copying fails when used with card readers equipped with firewalls (security mechanisms).
Applications: Typically used for simple IC card duplication, with relatively low security.
2. Standard IC Card (M1 Card)
Definition: A common type of smart IC card, such as elevator cards and access control cards.
Features: Sector 0 cannot be modified; other sectors can be repeatedly rewritten.
Note: The original cards issued by property management or card issuers are usually this type.
Applications: Widely used in property access control, elevator control, and similar scenarios.
3. ID Card
Definition: A card with a unique identification code (ID), similar to a UID card.
Features: Mostly passive RFID cards containing only a unique ID; other data cannot be modified or is not included.
Applications: Identity recognition, access control systems, and simple authentication scenarios.
4. FUID Card (Non-rewritable Anti-Shielding Card)
Definition: A special card where sector 0 can only be written once, after which it becomes a standard M1 card.
Features: Sector 0 cannot be rewritten; it offers anti-cloning and anti-shielding capabilities.
Use Case: Used when CUID copying fails; can bypass firewall protection mechanisms.
5. UFUID Card (Advanced Duplicate Card)
Definition: A hybrid card combining UID and FUID card features.
Features: Initially behaves like a UID card; after a card sealing operation, it transforms into an FUID card (i.e., a standard M1 card).
Use Case: Suitable for scenarios requiring advanced duplication and protection.
6. CUID Card (Rewritable Anti-Shielding Card)
Definition: A rewritable card with anti-shielding features.
Features: All sectors can be repeatedly rewritten; used as a substitute when UID card copying fails.
Advantages: Can bypass firewalls; ideal for complex duplication needs.
Conclusion
As a type of smart card, the CUID card utilizes Radio Frequency Identification (RFID) technology to enable fast identification and efficient management of objects. It offers advantages such as high efficiency, security, reliability, and scalability, and is widely used in logistics, warehousing, asset management, and access control. With the continued development of the Internet of Things (IoT), CUID cards are expected to become a standard tool for object identification and management in the future.
By implementing CUID cards, organizations can significantly enhance the efficiency and security of asset management, accelerating digital transformation and intelligent development across various industries.
The above is a brief introduction to CUID cards. If you are looking for a professional RFID/NFC manufacturer, please feel free to contact CBT. With 28 years of experience in the RFID industry, we look forward to working with you.
All Rights Reserved: https://www.chipbond.com/article_cuid-card.html
Copyright Notice: This article is an original (translated) work by CBT. Please credit CBT as the source. If there are any concerns regarding copyright, please contact us directly.
