HID Prox & iCLASS
Smart Cards & RFID · 5 specs
Direct Answer
HID Prox and iCLASS are proprietary physical access control credentials developed by HID Global. They encompass legacy 125 kHz unencrypted Prox (such as 26-bit Wiegand H10301), 13.56 MHz read/write iCLASS smart cards, and modern Seos microprocessor cards utilizing AES-128 encryption.
Source: HID Global / ANSI/SIA CP-01 · Last reviewed Aug 28, 2026
Specs
| Operating Frequencies | 125 kHz (Prox) / 13.56 MHz (iCLASS / Seos) |
| Common Bit Formats | 26-bit H10301, 37-bit H10302/H10304, Corporate 1000 |
| Standard Compliance (iCLASS) | ISO/IEC 15693 and ISO/IEC 14443-A/B |
| Security Cryptography | None (Prox), 64-bit DES (Legacy iCLASS), AES-128 (iCLASS SE / Seos) |
| Reader Interface Protocol | Wiegand / OSDP (Open Supervised Device Protocol) |
HID Prox (125 kHz) Vulnerability
Standard 125 kHz HID Prox cards transmit their facility code and card number in plain text without any encryption or challenge-response handshake. The standard 26-bit H10301 format can be captured from up to several feet away using long-range snooper antennas and instantly replayed or cloned to blank T5577 key fobs.
iCLASS Standard Key Compromise and Migration to Seos
In 2010, security researchers extracted the universal 'Standard Key' hardcoded into legacy iCLASS readers (HID Master Key), allowing arbitrary cloning of 13.56 MHz iCLASS cards. HID introduced iCLASS SE and Seos to replace legacy iCLASS with mutual challenge-response authentication, diversified AES-128 keys, and secure mobile credential provisioning.