Find the possible deciphering transformations, Computer Network Security

Assignment Help:

Question:

(a) A string of ciphertext was enciphered using an a±ne transformation of single letters in a 28-letter alphabet consisting of A to Z, a blank and a?, where A to Z have numerical equivalents 0 to 25, blank=26, ?=27. A frequency analysis reveals that the the first, second and third most common letters of this ciphertext are B, ? and I, respectively. Suppose that the first and second most common letters in an English language text written in this 28-letter alphabet are ` '(blank) and E, respectively.

(i) Find the possible deciphering transformations.

(ii) Using the fact that T, is the third most common letter in the English language (of our 28 letters), find the right deciphering transformation.

(b) The ciphertext

¡GSTMTSI XJMUIGHRFKYMV

was generated using a 2£2 enciphering matrix with a 29¡letter alphabet, where A to Z have numerical equivalents 0 to 25, blank=26, !=27, and ¡ = 28. Given that the last five letters of the plaintext are A¡ONE, determine the complete plaintext.


Related Discussions:- Find the possible deciphering transformations

Security policies, implementing password policy in organisation

implementing password policy in organisation

Explain why spreadsheets are so useful, Question: Spreadsheet packages ...

Question: Spreadsheet packages are widely used in Business. a) Explain why spreadsheets are so useful. b) Spreadsheet files are sometimes saved for use by other software

Csma/ca, CSMA/CA Wireless needs collision avoid ness rather than colli...

CSMA/CA Wireless needs collision avoid ness rather than collision checking. Transmitting computer puts very short codes to receiver. Receiver responds with short message getti

Representation of a tcp header, (a) Figure is a representation of a TCP hea...

(a) Figure is a representation of a TCP header. For each of the fields lettered from A to G, state the name of the field and provide a brief explanation for the function of each fi

Cracking the Vigenere Cipher, The following message was enciphered with a V...

The following message was enciphered with a Vigenère cipher. aikiaawgfspxeppvjabjnivulfznzvkrlidamsmyamlvskniyffdpbwtnxsvvbtnamvltsefoeycztkomylmerkwrs deusjgecmzkwvnreeyp

Define full-duplex., A  full-duplex (FDX) , accepts communication in both...

A  full-duplex (FDX) , accepts communication in both ways, and, unlike half-duplex, accept this to occur simultaneously. Land-line telephone networks are full-duplex, since they

Limitations of firewall, Limitations of firewall Firewalls cannot prote...

Limitations of firewall Firewalls cannot protect a network if security rules are not followed properly by an organization or if the rules are not defined properly. Firewalls ar

Factors of informtion security, Confidentiality Confidentiality of inform...

Confidentiality Confidentiality of information ensures that only those with sufficient privileges may access specific information. When unauthorized individuals can access inform

Access control devices-cryptography, ACCESS CONTROL DEVICES Successful a...

ACCESS CONTROL DEVICES Successful access control system includes number of components, which depends on system’s requirements for authentication and authorization. Powerful auth

Vulnerability scanners, VULNERABILITY SCANNERS Active vulnerability scan...

VULNERABILITY SCANNERS Active vulnerability scanners scan networks for detailed information, it initiate traffic to determine security holes. This scanner identifies usernames a

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd