RBS Cryptosystem

Abstract

Redundant Bit Security (RBS) is a lightweight symmetric encryption algorithm that targets the resource-constrained RFID devices. Unlike its existing counterparts, RBS simultaneously provide confidentiality, authentication, and integrity of the plaintext by inserting hash-generated redundant bits among the already modified plaintext-data. Using a flexible-length hash algorithm in the RBS hardware implementation allows RBS to support different key sizes which implies flexibility in the security level. RBS hardware implementation consists of two parts. The first part implements the redundant bit generator by implementing a modified version of MAC generator that is compatible with block ciphers instead of the original MAC generator designed for stream ciphers. The second part of the RBS implementation targets implementing the encryption/decryption process. The encryption/decryption process is integrated with the transmission and reception modules of the RFID transponder. The RBS implementation presented supports online key size selection. This implies that the number of redundant bits, and accordingly the security level, in RBS is adjustable without changing the underlying hardware. This feature allows tags with the same hardware to operate with different key sizes.