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Note for Cyber Security - CS by kishan chandra

  • Cyber Security - cs
  • Note
  • GD Goenka University -
  • Computer Science Engineering
  • B.Tech
  • 1 Topics
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Kishan Chandra
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1. Explain CIA concepts in Cyber Security. ANS:- Confidentiality, integrity and availability, also known as the CIA triad, is a model designed to guide policies for information security within an organization. The model is also sometimes referred to as the AIC triad (availability, integrity and confidentiality) to avoid confusion with the Central Intelligence Agency. The elements of the triad are considered the three most crucial components of security. In this context, confidentiality is a set of rules that limits access to information, integrity is the assurance that the information is trustworthy and accurate, and availability is a guarantee of reliable access to the information by authorized people. Confidentiality: Confidentiality is roughly equivalent to privacy. Measures undertaken to ensure confidentiality are designed to prevent sensitive information from reaching the wrong people, while making sure that the right people can in fact get it: Access must be restricted to those authorized to view the data in question. It is common, as well, for data to be categorized according to the amount and type of damage that could be done should it fall into unintended hands. More or less stringent measures can then be implemented according to those categories. Sometimes safeguarding data confidentiality may involve special training for those privy to such documents. Such training would typically include security risks that could threaten this information. Training can help familiarize authorized people with risk factors and how to guard against them. Further aspects of training can include strong passwords and password-related best practices and information about social engineering methods, to prevent them from bending data-handling rules with good intentions and potentially disastrous results. A good example of methods used to ensure confidentiality is an account number or routing number when banking online. Data encryption is a common method

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of ensuring confidentiality. User IDs and passwords constitute a standard procedure; two-factor authentication is becoming the norm. Other options include biometric verification and security tokens, key fobs or soft tokens. In addition, users can take precautions to minimize the number of places where the information appears and the number of times it is actually transmitted to complete a required transaction. Extra measures might be taken in the case of extremely sensitive documents, precautions such as storing only on air gapped computers, disconnected storage devices or, for highly sensitive information, in hard copy form only. Integrity: Integrity involves maintaining the consistency, accuracy, and trustworthiness of data over its entire life cycle. Data must not be changed in transit, and steps must be taken to ensure that data cannot be altered by unauthorized people (for example, in a breach of confidentiality). These measures include file permissions and user access controls. Version control maybe used to prevent erroneous changes or accidental deletion by authorized users becoming a problem. In addition, some means must be in place to detect any changes in data that might occur as a result of non-human-caused events such as an electromagnetic pulse (EMP) or server crash. Some data might include checksums, even cryptographic checksums, for verification of integrity. Backups or redundancies must be available to restore the affected data to its correct state. Availability: Availability is best ensured by rigorously maintaining all hardware, performing hardware repairs immediately when needed and maintaining a correctly functioning operating system environment that is free of software conflicts. It’s also important to keep current with all necessary system upgrades. Providing adequate communication bandwidth and preventing the occurrence of bottlenecks are equally important. Redundancy, failover, RAID even highavailability clusters can mitigate serious consequences when hardware issues do occur. Fast and adaptive disaster recovery is essential for the worst case

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scenarios; that capacity is reliant on the existence of a comprehensive disaster recovery plan (DRP). Safeguards against data loss or interruptions in connections must include unpredictable events such as natural disasters and fire. To prevent data loss from such occurrences, a backup copy may be stored in a geographically-isolated location, perhaps even in a fireproof, waterproof safe. Extra security equipment or software such as firewalls and proxy servers can guard against downtime and unreachable data due to malicious actions such as denial-of-service (DoS) attacks and network intrusions. 2. Explain Access Control Matrix. Ans,:- In computer science, an Access Control Matrix or Access Matrix is an abstract, formal security model of protection state in computer systems, that characterizes the rights of each subject with respect to every object in the system. It was first introduced by Butler W. Lampson in 1971. An access matrix can be envisioned as a rectangular array of cells, with one row per subject and one column per object. The entry in a cell – that is, the entry for a particular subject-object pair – indicates the access mode that the subject is permitted to exercise on the object. Each column is equivalent to an access control list for the object; and each row is equivalent to an access profile for the subject. According to the model, the protection state of a computer system can be abstracted as a set of objects, that is the set of entities that needs to be protected (e.g. processes, files, memory pages) and a set of subjects, that consists of all active entities (e.g. users, processes). Further there exists a set of rights of the form, where , and. A right thereby specifies the kind of access a subject is allowed to process object. 3. Explain Symmetric Key Distribution, Public Key Cryptography and Public Key Distribution. Ans. Symmetric encryption is a form of computerized cryptography using a singular encryption key to guise an electronic message. Its data conversion uses a mathematical algorithm along with a secret key, which results in the inability to make sense out of a message. Symmetric encrpytion is a two-way algorithm because the mathematical algorithm is reversed when decrypting the message along with using the same secret key. Symmetric encryption is also known as private-key encryption and secure-key encryption. The two types of symmetric encryptions are done using block and stream algorithms. Block algorithms are applied to blocks of electronic data. Specified set

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lengths of bits are transformed, while simultaneously using the selected secret key. This key is then applied to each block. However, when network stream data is being encrypted, the encryption system holds the data in its memory components waiting for the blocks in their entirety. The time in which the system waits can yield a definite security gap, and may compromise data protection. The solution involves a process where the block of data could be lessened and combined with previous encrypted data block contents until the rest of the blocks arrive. This is known as feedback. When the entire block is received, then it is encrypted. Conversely, stream algorithms are not held in the encryption system memory, but arrive in data stream algorithms. This type of algorithm is considered somewhat more secure, since a disk or system is not holding on to the data without encryption in the memory components. Public key Cryptography :- Public key cryptography (PKC) is an encryption technique that uses a paired public and private key (or asymmetric key) algorithm for secure data communication. A message sender uses a recipient's public key to encrypt a message. To decrypt the sender's message, only the recipient's private key may be used. The two types of PKC algorithms are RSA, which is an acronym named after this algorithm's inventors: Rivest, Shamir and Adelman, and Digital Signature Algorithm (DSA). PKC encryption evolved to meet the growing secure communication demands of multiple sectors and industries, such as the military. PKC is also known as public key encryption, asymmetric encryption, asymmetric cryptography, asymmetric cipher, asymmetric key encryption and Diffie-Hellman encryption. Public Key Distribution:- A key distribution center (KDC) in cryptography is a system that is responsible for providing keys to the users in a network that shares sensitive or private data. Each time a connection is established between two computers in a network, they both request the KDC to generate a unique password which can be used by the end system users for verification. 4. Explain a. Digital Signatures Ans. -A digital signature guarantees the authenticity of an electronic document or message in digital communication and uses encryption techniques to provide proof of original and unmodified documentation .Digital signatures are used in ecommerce, software distribution, financial transactions and other situations that rely on forgery or tampering detection techniques .A digital signature is also known as an electronic signature. A digital signature is applied and verified, as follows:  The document or message sender (signer) or public/private key supplier shares the public key with the end user(s).

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