DALLAS DS1963S handbook
Datasheet
DS1963S is a financial iButton with SHA-1 functionality and a 4k-bit read/write data area. It has a 4096-bit non-volatile (NV) memory, divided into 16 pages of 256 bits each. It also features independent 64-bit keys and 32-bit read-only, non-rolling page write counters. The device also includes a 512-bit SHA-1 engine that can calculate a 160-bit message authentication code (MAC) and can be used as a co-processor for roaming iButtons or hosts.