White Paper 3: Why are 1-Wire SHA-1 Devices Secure?

Abstract: This document shows why 1-Wire® and iButton® SHA-1 devices are secure by introducing possible attack scenarios and explaining how the SHA-1 devices counter the attack in hardware or in a recommended usage procedure. Data and hardware authentication with 1-Wire devices are the key concepts presented for various types of service applications including access control and electronic cash. Since 1-Wire/iButton SHA-1 devices are portable tokens that can create a message authentication code (MAC) based on a random challenge using a cryptographically good hash; they are an ideal choice for the above-mentioned service applications.