Research And Implementation Of The U-Disk With Identity Authentication And Data Encryption

With the rapid development of computer technology, the transmission of information is becoming more speedy and conveniently than before. Simultaneously, people are calling for higher requirements of information storage medium's safety. As the new generation of safely movable storage device, encryption U-disk obtains widespread application. In present, encryption U-disk has some disadvantages such as low security, slow speed to encrypt data, complex operation, expensive price and so on.This thesis analyzes the technical character of Universal Serial Bus (USB) protocol. Based on researching Advanced Encryption Standard (AES) algorithm, one kind of new encryption U-disk design scheme is proposed, which integrates data encryption, data decryption, identity authentication. The MCU MC9S12UF32 is adopted as main controller in this system and it realizes encryption U-disk's hardware design. The thesis introduces design and implementation of the encryption U-disk's software in detail, which includes implementation of USB protocol, operation of Flash chip, design and implementation of authentication and encryption modules.In the thesis, the problem of bad block in Flash chip has been solved by the technique of maped table contains logical address. The thesis adopts a strategy of partition Flash chip to achieve user authentication function, uses a CD-ROM partition to store user login program to solve the problem of application program being destroyed intentionally or unintentionally, through a method of authentication and AES data encryption to protect security of information stored in the files confidential partition. The data encryption adopts the AES algorithm. Aiming at the trait that MCU's resource is limited, one kind of selective encryption strategy is proposed, which carries on the part encryption and decryption operation on the stored data, and the AES algorithm is optimized to realise. The thesis introduces the process of debugging the system and testing of the system.The design proposal of the U-disk with identity authentication and data encryption is implemented in this thesis. After many experiments, it proves that the encryption U-disk by this thesis can operate correctly and stably, speed of data writing and data reading may achieve 1.54MB/s and 6.30MB/s separately. The encryption U-disk can ensure the security of the data in storage, and it has certain practical application value.