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Computer security is information security as applied to computers and networks. The field covers all the processes and mechanisms by which computer-based equipment, information and services are protected from unintended or unauthorized access, change or destruction. Computer security also includes protection from unplanned events and natural disasters Morrie Gasser: Building a secure computer system 1988. In computer security, vulnerability is a weakness which allows an attacker to reduce a system’s information assurance. Vulnerability is the intersection of three elements: a system susceptibility or flaw, attacker access to the flaw, and attacker capability to exploit the flaw. To exploit vulnerability, an attacker must have at least one applicable tool or technique that can connect to a system weakness. In this frame, vulnerability is also known as the attack surface. Vulnerability management is the cyclical practice of identifying, classifying, remediating, and mitigating vulnerabilities” This practice generally refers to software vulnerabilities in computing systems. (Paul A. et al, 2008).

A security risk may be classified as vulnerability. The usage of vulnerability with the same meaning of risk can lead to confusion. The risk is tied to the potential of a significant loss. Then there are vulnerabilities without risk: for example when the affected asset has no value. A vulnerability with one or more known instances of working and fully implemented attacks is classified as an exploitable vulnerability — a vulnerability for which an exploit exists. The window of vulnerability is the time from when the security hole was introduced or manifested in deployed software, to when access was removed, a security fix was available and deployed, or the attacker was disabled. Security bug (security defect) is a narrower concept: there are vulnerabilities that are not related to software: hardware, site, personnel vulnerabilities are examples of vulnerabilities that are not software security bugs (Paul A. et al, 2008).

Security by Design

One way to think of computer security is to reflect as one of the main features.

Some of the techniques in this approach include:

The principle of least privilege- this is a case where each part of the system has only the privileges that are needed for its function; that way even if an attacker gains access to that part, they have only limited access to the whole system.
Automated theorem proving- to prove the correctness of crucial software subsystems.
Code reviews and unit testing are approaches to make modules more secure where formal correctness proofs are not possible.
Defense in depth, where the design is such that more than one subsystem needs to be violated to compromise the integrity of the system and the information it holds.
Default secure settings, and design to “fail secure” rather than “fail insecure”. Ideally, a secure system should require a deliberate, conscious, knowledgeable and free decision on the part of legitimate authorities in order to make it insecure.

Audit Trails tracking system activity, so that when a security breach occurs, the mechanism and extent of the breach can be determined. Storing audit trails remotely, where they can only be appended to, can keep intruders from covering their tracks.

Full disclosure to ensure that when bugs are found the “window of vulnerability” is kept as short as possible (Paul A. et al, 2008).

Security Architecture

Security architecture can be defined as the design artifacts that describe how the security controls (security countermeasures) are positioned, and how they relate to the overall information technology architecture. These controls serve to maintain the system’s quality attributes:

Assurance services
Hardware Mechanisms that protect computers and data

Hardware bases or assisted computer security offers an alternative to software only computer security. Devices such as dongles, case intrusion detection, drive locks, or disabling USB ports, or CD ROM Drives may be considered more secure due to the physical access required in order to be compromised. (

Secure Operating System

One use of the term computer security refers to technology to implement a secure operating system. Much of this technology is based on science developed in the 1980s and used to produce what may be some of the most impenetrable operating systems ever. Though still valid, the technology is in limited use today, primarily because it imposes some changes to system management and also because it is not widely understood. Such ultra-strong secure operating systems are based on operating system kernel technology that can guarantee that certain security policies are absolutely enforced in an operating environment. An example of such a computer security policy is the Bell-LaPadula Model. The strategy is based on a coupling of special microprocessor hardware features, often involving the memory management unit, to a special correctly implemented operating system kernel. This forms the foundation for a secure operating system which, if certain critical parts are designed and implemented correctly, can ensure the absolute impossibility of penetration by hostile elements. This capability is enabled because the configuration not only imposes a security policy, but in theory completely protects itself from corruption. Ordinary operating systems, on the other hand, lack the features that assure this maximal level of security. The design methodology to produce such secure systems is precise, deterministic and logical.

Systems designed with such methodology represent the state of the art of computer security although products using such security are not widely known. In sharp contrast to most kinds of software, they meet specifications with verifiable certainty comparable to specifications for size, weight and power. Secure operating systems designed this way are used primarily to protect national security information, military secrets, and the data of international financial institutions.

These are very powerful security tools and very few secure operating system have certified at the highest level to operate over the range of “Top Secret” to “unclassified” (including Honeywell SCOMP, USAF SACDIN, NSA Blacker and Boeing MLS LAN) the assurance of security depends not only on the soundness of the design strategy, but also on the assurance of correctness of the implementation, and therefore there are degrees of security strength defined for COMPUSEC. The common criteria quantifies security strength of products in terms of two components, security functionality and assurance level (such as EAL levels), and these are specified in a Protection Profile for requirements and a Security Target for product descriptions. None of these ultra-high assurances secure general purpose operating systems have been produced for decades or certified under common criteria.

In USA parlance, the term High Assurance usually suggests the system has the right security functions that are implemented robustly enough to protect DoD and DoE classified information. Medium assurance suggests it can protect less valuable information, such as income tax information. Secure operating system designed to meet medium robustness levels of security functionality and assurance has seen wider use within both government and commercial markets. Medium robust systems may provide the same security functions as high assurance secure operating systems but do so at a lower assurance level (such as Common Criteria level EAL4 or EAL5). Lower level means we can be less certain that the security functions are implemented flawlessly, and therefore less dependable. These systems are found in use on web servers, guards, database servers, and management hosts and are used not only to protect the data stored on these systems but also to provide a high level of protection for network connections and routing services. (Morgan K., 2009)

Access Control List and Capability (computers)

Within computer systems, two security models capable of enforcing privilege separation are access control lists (ACLs) and capability-based security. The semantics of ACLs have been proven to be insecure in many situations, for example, the confused deputy problem. It has also been shown that the promise of ACLs of giving access to an object to only one person can never be guaranteed in practice. Both of these problems are resolved by capabilities. This does not mean practical flaws exist in all ACL-based systems, but only that the designers of certain utilities must take responsibility to ensure that they do not introduce flaws.

Capabilities have been mostly restricted to research operating systems and commercial OSs still use ACLs. Capabilities can, however, also be implemented at the language level, leading to a style of programming that is essentially a refinement of standard object-oriented design. An open source project in the area is the E language.

The most secure computers are those not connected to the Internet and shielded from any interference. In the real world, the most secure systems are operating systems where security is not an add-on.


Computer security is critical in almost any technology-driven industry which operates on computer systems. The issues of computer based systems and addressing their countless vulnerabilities are an integral part of maintaining an operational industry.

Cloud Computing Security

Security in the cloud is challenging, due to varied degrees of security features and management schemes within the cloud entities. In this connection one logical protocol base need to evolve so that the entire gamut of components operates synchronously and securely John R. Vacca (ed.): Computer and information security handbook. (Morgan K., 2009)

Despite significant advances in the state of the art of computer security in recent years, information in computers is more vulnerable than ever. Each major technological advance in computing raises new security threats that require new security solutions, and technology moves faster than the rate at which such solutions can be developed. We would be fighting a losing battle, except that security need not be an isolated effort: there is no reason why a new technology cannot be accompanied by an integrated security strategy, where the effort to protect against new threats only requires filling in a logical piece of a well-defined architecture.

I probably cannot change the way the world works, but understanding why it works the way it does can help me avoid the typical pitfalls and choose acceptable security solutions. This chapter explores some of the classic reasons why the implementation of security lags behind its theory.

Why are computer systems so bad at protecting information? After all, if it is possible to build a system containing millions of lines of software (as evidenced by today’s large operating systems), why is it so hard to make that software operate securely? The task of keeping one user from getting to another user’s files seems simple enough especially when the system is already able to keep track of each user and each file. In fact, it is far easier to build a secure system than to build a correct system. But how many large operating systems are correct and bug-free? For all large systems, vendors must periodically issue new releases, each containing thousands of lines of revised code, much of which are bug fixes. No major operating system has ever worked perfectly, and no vendor of an operating system has dared offer a warranty against malfunctions.

The industry seems resigned to the fact that systems will always have bugs. Yet most systems are reasonably dependable, and most of them adequately (but not perfectly) do the job for which they were designed. What is adequate for most functions, however, is not sufficient for security. If i find an isolated bug in one function of an operating system, i can usually circumvent it, and the bug will have little effect on the other functions of the system: few bugs are fatal. But a single security “hole” can render all of the system’s security controls worthless, especially if the bug is discovered by a determined penetrator. i might be able to live in a house with a few holes in the walls, but i will not be able to keep burglars out. (

Computer Security Policy

The examples and perspective in this section may not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page. (John M., 2010)

Cyber-security Act of 2010

On April 1, 2009, Senator Jay Rockefeller (D-WV) introduced the “Cyber-security Act of 2009 – S. 773” (full text) in the Senate; the bill, co-written with Senators Evan Bayh (D-IN), Barbara Mikulski (D-MD), Bill Nelson (D-FL), and Olympia Snowe (R-ME), was referred to the Committee on Commerce, Science, and Transportation, which approved a revised version of the same bill (the “Cyber-security Act of 2010”) on March 24, 2010. The bill seeks to increase collaboration between the public and the private sector on cyber-security issues, especially those private entities that own infrastructures that are critical to national security interests (the bill quotes John Brennan, the Assistant to the President for Homeland Security and Counterterrorism: “our nation’s security and economic prosperity depend on the security, stability, and integrity of communications and information infrastructure that are largely privately owned and globally operated” and talks about the country’s response to a “cyber-Katrina”.), increase public awareness on cyber-security issues, and foster and fund cyber-security research. Some of the most controversial parts of the bill include Paragraph 315, which grants the President the right to “order the limitation or shutdown of Internet traffic to and from any compromised Federal Government or United States critical infrastructure information system or network.” The Electronic Frontier Foundation, an international non-profit digital rights advocacy and legal organization based in the United States, characterized the bill as promoting a “potentially dangerous approach that favors the dramatic over the sober response” (Maj. Dawood F., 2012).

1.2 Problem Statement

There is a cogent need for security measurement on PCs basically to ensure integrity of data from being compromised and most security systems predefined by windows operating system are mastered by hackers or intruders. This advent led to the development of a third party system which can run on windows platform and perform the same functionality with enhanced features. These features are accentuated with time scheduling system in which time to lock and unlock automatically are set.

1.3 Aims and Objectives

The aim of this project is to provide additional security to an existing password security already incorporated by the Microsoft Windows Operating System in order to strengthen the security level of a PC.

The aims are illustrated as follows

To design a precise lock system for personal computers (PCs) that can be controlled and managed locally.
To ensure adequate security measure and protect the PCs with a third party security system.
To strengthen the security level of personal computers by ensuring its applicability across subsystem
1.4 Scope of Study

The system is very seamless and robust as its area of functionality is elongated to secure the system from unauthorized access. Sequel to development of several security measures, password method is seen to be absolutely perfect system to ensure security with much of ado. This method is a standalone system and it enhances settings that can be used to automate the lock depending on time schedule and restriction privilege.

1.5 Significance of the Study

The essence of this application is to provide adequate security measure to counter any attack from unauthorized users by enabling an automated system that locks the system if remains idle for certain period of time as scheduled by the user.

Therefore the crucial points that this application emphasizes on are listed below.

Protect the user’s computer system if the operational module of the system remains idle for certain specified period of time.
hashing the login using MD5 encryption method
Its application is strictly running of non-database system

1.6 Project Layout

Chapter one covers the introductory part and the background study. This chapter illustrates introduces the readers to the topic definition of the project work and what is expected to cover as a whole.
Chapter two is Literature Review; this focuses on the related topics and emphasize on the applicability of intended projects with respect to their functionalities as a standard requirement in a real life, magazine, journals or articles.
Chapter Three is a system analysis which illustrates the analysis engaged in carrying out the proposed system with regard to user’s requirements and software engineering development life-cycle.
Chapter four is a system design and implementation, this focuses on design pattern and architectures that best fit for the designing of the proposed system. The design can be interpreted with conceptual data structure and Unified Model Language for visual representation of data entity relationship.
Chapter Five is a conclusion, summary and recommendation. The conclusion is a report or documentation, the summary gives the brief description of the proposed system and recommendation illustrates areas that need improvement, adjustment and work-on to see better way to handle the process in term of efficiency, response time and throughput.

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