HITAG 1 vs HITAG 2

Choose HITAG 1 if you need significantly larger user memory and dual-key cryptographic architecture. With 224 bytes of read/write user memory (compared to HITAG 2's 16 bytes), HITAG 1 suits applications requiring storage of more credential data, transaction logs, or multi-purpose access tokens. It features two separate 32-bit cryptographic keys (Key A and Key B) plus four 32-bit logdata values, enabling more complex access hierarchies and audit trail functionality. The 2048-bit total memory footprint makes HITAG 1 appropriate for vehicle immobilizers and industrial access systems where multiple data fields must be stored alongside security credentials. Both chips operate at 125 kHz with proprietary protocols and Manchester coding, but HITAG 1's larger memory architecture supports more sophisticated credential management in a single token. Choose HITAG 2 if you need backward compatibility with multiple standards and faster authentication with a stronger cipher. HITAG 2 implements a proprietary 48-bit crypto stream cipher (stronger than HITAG 1's 32-bit keys) with mutual authentication completing in approximately 36 milliseconds. Its three public emulation modes provide compatibility with MIRO/µEM H4000 readers (Mode A, Manchester), ISO 11784/11785 animal identification systems (Mode B, Biphase), and PIT-compatible readers (Mode C, Biphase), making it versatile for retrofit installations. With 16 bytes of user memory across pages 4-7, HITAG 2 suffices for simple credential storage in vehicle immobilizers, hotel key cards, and basic access control where the 32-bit serial number and authentication matter more than data storage. The page-level write protection and one-time programmable lock bits for pages 1-3 offer granular security control despite the smaller memory footprint.