Advanced Network Security: Encryption, Cloud Storage, Digital Signatures, and Trojan Horse Attacks

This article discusses advanced network security topics such as symmetric key encryption, full-disk encryption, file-based encryption, digital signatures, and Trojan horse attacks. It provides recommendations for software developers and users. The article also explains the security ramifications of cloud storage for backup. The subject is relevant to courses in computer science, cybersecurity, and information technology.

Running head: ADVANCED NETWORK SECURITY
Advanced Network Security
Name of the Student
Name of the University
Author Note

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Question 1:
a) Provide a general explanation of how symmetric key encryption of files or disks work.
Symmetric key encryption for files or disks is a process by which a single key is used to
encrypt or decrypt a message. This implies that a person who is encrypting the message must
provide the recipient with the key for them to decrypt it (Saranya, Mohanapriya and Udhayan
2014). To explain the process further, it could be said that in symmetric encryption, senders
encrypt messages but without the same key provided to the recipient, it cannot be decrypted
again. For this purpose, the cipher text has to be sent separately to the recipient for decrypting
the encrypted text. This method might be fast from the viewpoint of implementation, but it also
has weaknesses. The weakness is that, if the key is intercepted by a hacker, the message can
easily be decrypted.
b) With respect to the file server, explain to the company what is full-disk encryption and
file-based encryption, and explain the tradeoffs between the two approaches. Include
recommended technologies.
Full-disk Encryption: At the file server level, full-disk encryption can be explained as an
encryption process that works by automatically converting a file-server data in a form (Saranya,
Mohanapriya and Udhayan 2014). This is impossible for any third person to understand who do
not possess the key to undo this conversation.
File-based Encryption: At the file-server level, file-based encryption is an encryption process
that provides keys according to each file in the server so that they could be unlocked
independently.

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Tradeoff between the two approaches: The general tradeoff between the two approaches
requires that both of these technologies provide good protection to encrypted files when it comes
to data theft, however, it depends only on the way by which a person handles the encryption
keys.
c) Explain to the company any security ramifications of cloud storage to backup. Include
reasons why or why not there are security ramifications.
The security ramification of cloud storage in case of backup that there are chances of data
theft is very likely to occur in these matters. However, it is not justified to put forward the fact
that cloud storage is an unsafe option for data backup (Rudd et al. 2017). Although, the tempting
target that they provide by being available in a much bigger virtual storage space makes it
vulnerable to data theft. There are data theft issues because the cloud backup system forms an
environment which is beyond control, therefore, there are security ramifications present when a
company would like to create a backup in the cloud-based virtual space.
d) Provide a general explanation of how digital signatures work, and what problems they
solve for the company.
A digital signature is regarded as the digital counterpart of a traditional and authentic
handwritten signature. However, it provides much more inherent security as it provides solution
to the problem of tampering the traditional signature produced by hand (Hoffstein et al. 2015). It
is also based on encryption process of public key or asymmetric cryptography using a public key
algorithm. It uses the mechanism where two mathematically linked keys are used, one public and
one private key. In one way of hash data, the signature is to be provided, the private key is then
provided to encrypt the hash code. The hash algorithm is the digital signature.

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Digital signature solves the problem of authentication of a person, since original handwritten
signatures can be forged and digital signatures cannot.
e) Regarding both encryption on the file server and use of digital signatures, explain to the
company what keys will be in use and provide recommendations on managing, sharing and
changing keys.
In case of digital signatures for a company, the keys that would be used for handling the
digital signatures are the private keys and the public keys.
For managing, sharing and changing the keys for digital signatures, the use of the hash keys
require the signer’s public key to decrypt the hash (Jain et al. 2015). The managing and sharing
of the digital signatures has to be perfectly done so that it cannot be decrypted by unauthorized
personnel.
Question 2:
a) What are the motivations and goals of malicious users in using the Trojan horse attacks?
Include in your answer examples of negative impact of such attacks on users and software
developers.
There are different mindsets behind a hacker’s motive of hacking but using a Trojan horse
malware means that the hacker want to impersonate someone else’s identity as their own. The
things that could motivate a hacker into using a Trojan horse malware to hack is to get hold of
the encryption key form a developer’s end (Wright and Cache 2015). This helps a hacker to map
every encrypted part of a password a user types down. The enabling of unauthorized access
makes a hacker use Trojan horse malware.

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This definitely forms a negative impact to a user as this means breaching of personal and
confidential information. Every individual has a right to their private information. For example,
if a user is robbed off his or her bank account details by a hacker using Trojan horse malware, it
has a high risk of losing of the user’s money. Whereas, the developers who create these software
impermeable to hacking face the wrath of the seniors for their failure in developing a hack-proof
application.
b) Select two examples of real Trojans or malware distributed via reputable sources, and
describe those examples.
Example 1: As per the latest news, in July the Japanese parliament suffered a malicious
Trojan horse attack after a politician opened a link transferred via email. The Trojan horse attack
has been reported to be from a reputed Chinese organization (Jansen and Leukfeldt 2016). The
attack infected the lower house of the Japanese parliament infecting all the computers in service.
However, the damages incurred by the data breach are still unclear.
Example 2: News of NotPetya first broke on 27 June in Ukraine and the Netherlands. Bothe
the countries confirmed hacking attacks that affected their systems. Soon, similar incidents were
confirmed by Ukraine’s government, the British advertising group WPP, and the offices of
multinationals in Spain. It was found that it quickly traced the attacks to Petya, a form of
ransomware which encrypts the Master Boot Record.

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c) What role can file hashes, digests, or signatures play in securing downloads? What are
the limitations of these techniques?
Hash functions are essentially necessary since they are one of the parts of the process that is
performed during the creation of digital signatures (Ince 2017). Therefore, they provide the keys
to authenticate any download.
The message digest helps in identifying any duplicate or potentially harmful download. It is a
cryptographic hash function created by a one-way hashing formula that is designed to protect the
integrity of a piece of data to warn the copyright owner of any legalized data if someone is using
their original work and modifying it without having any authorization.
d) List and explain recommendations should be given to software developers in distributing
software.
 The developer shall identify and document all static and dynamic register
 It should be kept in mind that only the software listed by the vendors is installed
 Software licensing is to be done according to the nature of the developed software
 Not licensing a software but claiming copyright over it shall abide the respective
country’s legislations
 Open source business models should keep in mind the media distribution, branding and
post-sales support

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e) List and explain recommendations should be given to users who download software.
Before downloading any software, the user has to make sure that the software is trustworthy
and may not bring about any malicious software attacks on the systems used (Ince 2017). The
recommendations for a user to download a software is as listed as below:
 Searching of curated lists: Without searching for the software on search engines, it
is recommended to search curated lists for the software.
 Trusting the developer: A developer can only be trusted if its name is heard of or
the organization that develops the software is unanimously accepted.
 Searching for reviews: It is essentially necessary that reviews of previous users be
searched for and looked about before downloading a software.

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Reference
Hoffstein, J., Pipher, J., Schanck, J.M., Silverman, J.H. and Whyte, W.J., Security Innovation
Inc., 2017. Digital signature method. U.S. Patent 9,722,798.
Ince, D. ed., 2017. A Dictionary of the Internet. Oxford University Press.
Jain, N., Stiller, B., Khan, I., Makarov, V., Marquardt, C. and Leuchs, G., 2015. Risk analysis of
Trojan-horse attacks on practical quantum key distribution systems. IEEE Journal of Selected
Topics in Quantum Electronics, 21(3), pp.168-177.
Jansen, J. and Leukfeldt, R., 2016. Phishing and malware attacks on online banking customers in
the Netherlands: a qualitative analysis of factors leading to victimization. International Journal
of Cyber Criminology, 10(1), p.79.
Rudd, E.M., Rozsa, A., Günther, M. and Boult, T.E., 2017. A Survey of Stealth Malware
Attacks, Mitigation Measures, and Steps Toward Autonomous Open World Solutions. IEEE
Communications Surveys & Tutorials, 19(2), pp.1145-1172.
Saranya, K., Mohanapriya, R. and Udhayan, J., 2014. A review on symmetric key encryption
techniques in cryptography. International Journal of Science, Engineering and Technology
Research (IJSETR), 3(3), pp.539-544.
Shukla, J., 2015. Fixing computer files infected by virus and other malware. U.S. Patent
8,935,789.
Wright, J. and Cache, J., 2015. Hacking exposed wireless: wireless security secrets & solutions.
McGraw-Hill Education Group.