The illegal copying of electronic products is extremely serious. To address this issue, Atmel launched the AT88SC153 and AT88SC1608 encryption devices for anti-piracy in 1999, achieving certain results. However, since these two devices adopt plaintext transmission, their data is vulnerable to interception during communication. In 2003, Atmel introduced a new series of encryption devices with mutual authentication and ciphertext transmission—the AT88SC0104C~25616C series protocol authentication cards, with a maximum storage capacity of 32K bytes.

II. AT88SC0104C~25616C Series Protocol Authentication Cards
This series of protocol authentication cards are currently the most secure storage devices with the highest security performance. Compared with AT88SC1608 and AT88SC153, their most prominent feature is that all transmitted data is in ciphertext, ensuring the security of stored data.

Atmel has now recommended discontinuing the use of AT88SC1608 and AT88SC153 in new product development. In accordance with the requirements of Atmel's China Office, only the information approved for public disclosure by the manufacturer is introduced below. In fact, the AT88SC0104C~25616C series shares many similarities with AT88SC1608 and AT88SC153, such as access right registers and write-lock control registers. The operating principles of all devices in the AT88SC0104C~25616C series are identical, and the configuration areas vary with the card capacity.
1. Main Features
(1) Operating voltage: 2.7~5.5V; maximum clock frequency: 1.5MHz; compliant with ISO/IEC 7816-3 synchronous protocol.
(2) 256×8 bit configuration area, 4×32×8bit~16×2048×8bit storage units. Multiple application partitions with the same security level and password can be merged for use. Each partition is controlled by read and write passwords (8 sets of passwords, 1 read password and 1 write password per set, 3 bytes per password) with an error count of 8 times. If user partitions are merged, the read and write passwords point to the same set of passwords.
(3) Data security protection functions: 64-bit authentication protocol; ciphertext and checksum modes; ciphertext stream transmission mode; protocol authentication error counting; read/write access control passwords; password error counter; partition-specific access right configuration; voltage and clock frequency monitoring.
(4) Number of erase/write cycles: 100,000 times; data retention period: 100 years.
2. Package Types and Pins
The package types and pin functions of the AT88SC0104C~25616C series protocol authentication cards are shown in Figure 1.
Card Package             DIP-8 and SO-8 Packages
Figure 1  Package Diagram of AT88SC0104C~25616C Series Protocol Authentication Cards
3. Memory Composition of AT88SC0104C~25616C Series Protocol Authentication Cards

Note: P is the maximum user partition number (0~15); Q is the maximum byte address (018H~7F8H).
Figure 2  Memory Composition Diagram of AT88SC0104C~25616C Series Protocol Authentication Cards
The memory composition of the AT88SC0104C~25616C series protocol authentication cards is shown in Figure 2. Each user partition in Figure 2 has the same access address. The specific partition to be accessed is determined by the selected partition number. Access to the user partition memory is controlled by the control logic circuit, and the protection functions are configured during initialization (i.e., issuance) through the access right registers (AR), password right registers (PR), and passwords in the configuration area.
The structure of the AT88SC1616 configuration area is shown in Figure 3.