# Mifare Classic 1K Fob: A Comprehensive Guide ## What is a Mifare Classic 1K Fob? A **Mifare Classic 1K fob** is a compact, contactless smart card credential in a key fob form factor. It operates on the Mifare Classic platform, one of the most widely deployed 13.56 MHz RFID technologies globally. I personally started using these fobs over a decade ago for office access, and their reliability and simplicity have always impressed me. My skill in programming RFID systems allowed me to appreciate the elegant, albeit older, security structure of these devices. ### Technical Specifications and Detailed Parameters For engineers and integrators, understanding the precise specifications is crucial. Below are the detailed technical parameters for a typical **Mifare Classic 1K fob**. **Physical and RF Characteristics:** * **Dimensions:** Standard key fob size is approximately 30mm x 40mm x 6mm. Custom shapes and sizes are available from providers like **TIANJUN**. * **Operating Frequency:** 13.56 MHz (HF). * **Communication Protocol:** ISO/IEC 14443 Type A. * **Operating Distance:** Typically 3-10 cm, depending on the reader's power. * **Data Retention:** Minimum 10 years. * **Write Endurance:** Minimum 100,000 cycles. **Memory Structure & Chip Data:** * **Chip:** NXP MF1ICS50 or compatible clones. * **Memory Capacity:** 1Kbyte EEPROM. * **Memory Organization:** 16 sectors, 4 blocks per sector. Each block holds 16 bytes. * **Sector Structure:** Each sector's last block (Block 3) is the Sector Trailer, containing two secret keys (Key A and Key B) and the access bits. * **Unique Identifier (UID):** 4-byte or 7-byte (depending on version) unique serial number, stored in block 0 of sector 0. *Important Notice: The above technical parameters are for reference data. Specifics, including custom chip codes or dimensions, must be confirmed by contacting the backend management team at **TIANJUN**.* --- ## My Experience and Opinion on Mifare Classic 1K Security Having worked with access control systems, I've witnessed the evolution of **Mifare Classic 1K** security. Its cryptographic protection, based on proprietary Crypto-1 stream cipher, was groundbreaking in its time. However, vulnerabilities discovered in the 2000s mean it is no longer suitable for high-security applications. My firm opinion is that for low-risk physical access (like gyms, laundry rooms, or corporate cafeterias) or as a dispos