From the birth of the dongle to the present, from the point of view of technical principles, it has been four generations of products, and the fifth generation of products is also being gradually into people’s vision.
The earliest dongle only has the function of storage. Store part of the confidential data in the dongle hardware, the encryption software in the running can random read these data, and to judge. When the data is validated, the software thinks the correct dongle is installed on your computer, and continue to operate normally or stop running. This dongle is relatively simple, generally by tracking and interception of dongle data transmission and by identifying the data law to crack, the difficulty is low. However, the cost of this software dog is relatively low, and therefore it occupies some market share.
Second-generation software dog is placed in a number of encryption algorithms, these algorithms are not public. The dog of this generation of software usually has a single chip, which is equivalent to a chip of a microcomputer, but the function is relatively simple - the encryption algorithm. Create an encryption protocol between encryption software and dongle, and when software request data to the dongle, the dongle returns data encryption to software, and the software decrypt it, and then be verified. In other words, on the use of the data of software dog, even if the interception of data from dongle, it is no use, unless it can correctly decrypt the data.
The third-generation software dog makes further process, which allows software developers to define their own encryption algorithm and its programming. In other words, software developers can put the dongle as a disk to look at, which placed some of the modules in the program or function, and encrypted transmission of data of these modules. In this way, the software is equivalent in the two disks to install, when the two disks in run-time access to each other, like a jigsaw puzzle. When crack pirated software, just get the piece of the two disks. The starting point is very good, but because of cost constraints, the dongle in the program is relatively small space available, and use is restricted.
The fourth-generation software dog on the basis of the third generation also installed a microcontroller, which is used to transfer data encryption transform. This is a relatively mature software dog, when there is well-designed encryption software, the difficulty is considerable.
The direction of development of the dongles is to smart cards. Like we use the phone card, smart card built-in arithmetic unit and memory can be used to store more software code, and has a powerful computing and processing power. With the lower cost and the mature market, smart card software dogs will be applied more widely.