This paper introduced a non-source COM port encrypted dog based on HT(Holtek) Inc s I/O type MCU, and expounded the skills in hardware, software and the measures of anti-decryptions, and brought forth the HT MCU s communication protocol and the COM port s control methods with MSComm control unit in VB.

Implementation of JCE-based encryption and decryption;

Image encryption/decryption algorithm based on standard chaos map;

Hardware AES Encryption-decryption Extension of JavaCard Processor;

Encrypting and decrypting recovery of EFS(Encrypting File System);

Encrypt and decrypt of data communications based on m serial and disorder technology;

The study and practice of the VFP s table file encrypt & decrypt algorithms;

The reversibe methods of information encipher and decipher;

It elaborates the agreement encryption and the decipher principle as well as the concrete application.

especial to the encryption and decipher module, as the critical part in the input/out control unit.

With the wide-range application of computer network system in companies, more and more importance is attached to the safety of data, the encryption and deciphering of data is consequently the critical process of system safety.

In this paper, forming deciphering method about PC password is given and anаlyzed in detail the forming process of AMI CMOS password.

Aim\ The encryption and decode of EDBMS is designed.