This paper presents a secure authentication protocol for RFID systems using the AES algorithm. The authors address the security and privacy concerns of RFID systems, which are often overlooked due to the belief that cryptographic components are too costly for RFID tags. They propose a solution using strong symmetric authentication suitable for low power consumption and low die-size requirements. The authentication protocol uses AES as the cryptographic primitive, and the main contribution is a novel AES hardware implementation that encrypts a 128-bit block of data within 1000 clock cycles and has a power consumption below 9 μA on a 0.35 μm CMOS process. RFID systems are used for automatic identification of objects, and they work without line-of-sight, using radio frequency for data and energy transmission. The system consists of a tag and a reader, with the tag receiving energy from the reader. The paper discusses security issues such as consumer tracking, tag forgery, and unauthorized access to tag memory. It proposes a symmetric challenge-response authentication protocol based on AES, which is more efficient than asymmetric methods for RFID systems. The paper also presents an 8-bit AES architecture for RFID tags, which is more power-efficient than 32-bit implementations. The architecture includes a controller, RAM, and datapath, with the S-Box being a critical component for the SubBytes operation. The MixColumns operation is optimized by dividing it into four parts, reducing the circuit size and improving performance. The AES implementation has a chip area of 3,595 gates and a current consumption of 8.15 μA at a frequency of 100 kHz. The encryption of a 128-bit block requires about 1000 clock cycles. The paper concludes that the proposed AES implementation meets the requirements for integrating cryptographic components into RFID tags, with low power consumption and low die-size. Future work includes examining advanced authentication protocols for one-way and mutual authentication, and analyzing other authentication methods for RFID systems.This paper presents a secure authentication protocol for RFID systems using the AES algorithm. The authors address the security and privacy concerns of RFID systems, which are often overlooked due to the belief that cryptographic components are too costly for RFID tags. They propose a solution using strong symmetric authentication suitable for low power consumption and low die-size requirements. The authentication protocol uses AES as the cryptographic primitive, and the main contribution is a novel AES hardware implementation that encrypts a 128-bit block of data within 1000 clock cycles and has a power consumption below 9 μA on a 0.35 μm CMOS process. RFID systems are used for automatic identification of objects, and they work without line-of-sight, using radio frequency for data and energy transmission. The system consists of a tag and a reader, with the tag receiving energy from the reader. The paper discusses security issues such as consumer tracking, tag forgery, and unauthorized access to tag memory. It proposes a symmetric challenge-response authentication protocol based on AES, which is more efficient than asymmetric methods for RFID systems. The paper also presents an 8-bit AES architecture for RFID tags, which is more power-efficient than 32-bit implementations. The architecture includes a controller, RAM, and datapath, with the S-Box being a critical component for the SubBytes operation. The MixColumns operation is optimized by dividing it into four parts, reducing the circuit size and improving performance. The AES implementation has a chip area of 3,595 gates and a current consumption of 8.15 μA at a frequency of 100 kHz. The encryption of a 128-bit block requires about 1000 clock cycles. The paper concludes that the proposed AES implementation meets the requirements for integrating cryptographic components into RFID tags, with low power consumption and low die-size. Future work includes examining advanced authentication protocols for one-way and mutual authentication, and analyzing other authentication methods for RFID systems.