Data (date) Confidentiality and System (OS) Security

Data (date) Confidentiality and System (OS) Security

Since the reform and opening-up, we have made unremitting efforts by Chinese people to continuously develop computer technology and work closely with the cutting-edge technologies. Of course, this is the glorious mission and responsibility of countless programmers or yuan ~~~

Information security is getting more and more attention...

The main objectives of achieving the "security environment" are three threats: data confidentiality, data integrity, and system availability: attackers can steal confidential information from the system to expose the data. Attackers can modify the data stored in the system without authorization to tamper with the data. In this way, attackers can disrupt the system and refuse to provide services.

Data encryption principle: Data encryption is a type of data encryption science that converts data (plaintext) in the system into ciphertext, so that attackers cannot understand the data content even if they intercept encrypted data. Data encryption technologies include: data Encryption data decryption digital signature Signature Identification digital proof

The Data Encryption model consists of four parts: plaintext ciphertext encryption (decryption) Algorithm E (D) key K. The most basic encryption method is the shift replacement method.

In financial and commercial systems, many businesses require signatures or stamps on documents to verify their authenticity. When transmitting packets over computer networks, public keys can be used for electronic digital signatures to replace traditional signatures. (Digital Certificate)

Attacks from inside the system:

(1) attacks are carried out directly as legitimate users-> attackers first access the system through various channels to steal legitimate user identities and then read, modify, delete, and destroy files or resources in the system using the rights of legitimate users.

(2) indirect attacks through proxy functions-> an attacker places a proxy program into an application of the attacked system. When the application executes and calls the proxy program, the attacker will execute the pre-designed damages. task

In recent years, malware has been widely used for damages. There are two types of evidence to determine whether malicious software can run independently:

(1) independent running class: This type of software can be scheduled and executed by OS with worms.

(2) parasitic: cannot run independently, often parasitic in an application, such as the logic bomb Trojan Horse virus

Logic bomb: A logical bomb is an early malware. He was originally a programmer from a company who was trying to prevent him from being suddenly fired and put in a broken program (logical bomb) in the OS in advance) as long as the programmer enters the password every day, the program will not attack, but if the programmer is suddenly dismissed without warning, the program will be detonated because the password logic bomb cannot be obtained the next day-execute a destructive program this program usually causes normal programs to interrupt and randomly delete files, damage all files on the hard disk, or even cause system crashes.

Trap door ): the trap door is actually a piece of code that enters a hidden entry point of a program. The programmer skips the normal verification process through the trap door to debug the program. However, if malicious people are used for unauthorized access this constitutes a serious threat to system security.