Answer to Question #160713 in Computer Networks for Shuvo

Question

Mobile phones are considered to be the most common communication devices in history, mobile phones are not only used for casual greetings but also, sending and receiving important data such as, social security numbers, bank account details and passwords. Public key cryptography is a proven security solution, which can be used to secure the mobile communications. ABC company have been proposed; server-based framework public key cryptography solution to secure the mobile communications. Third party servers were used to check the certificates, authenticating the communicating parties, key distribution, etc. The proposed framework consists two type of ciphers; i) Public key Cryptosystem (RSA) and, ii) decrypt messages through the digital signature. There are four scenarios to be considered order security requirement of integrity and confidentiality; based on that scenarios answer the following questions:

 

a.  Scenario 1: Show the security design and calculation steps for digital signature by figure and explain on how to calculate?

 

b. Scenario 2: Based on Scenario 1, show the security design sequences and calculation steps for one-way hash algorithm by figure and provide justification on the usage of one-way hash algorithm? Then, list the Properties of Hash Algorithm?

 

 

c.  Scenario 3: Based on Scenario1, show the security design sequences and calculation steps for RSA by figure and explain how to use it to distribute the keys?

 

 

d. Scenario4: Based on Scenario 3, show the security design sequences and calculation steps for private key cipher by figure and explain how to use it for encrypt and decrypt messages?

 

Answer 1

The process to use digital signature are listed below-

1. We need to calculate the message digest - Hash value of the message, which is called the message digest. It is calculated by applying some cryptographic hashing algorithms.
2. Calculate digital algorithm - The most common algorithm which is often used RSA,DSA, and ECDSA algorithm.

Verification of digital signature -