ICT133 Structured Programming

Flowgorithm, and examinethe flowchart for Vigenere Cipher, a symmetric encryption, . A pictorial representation of symmetric key encryptionis shown in Figure Q1.1. Symmetric key encryption uses the samesecret keyto encrypt and decrypt a message: ?The sender usesasecret key to encrypt a plain text (the message) into cipher text (scrambled text that is intelligible).?The recipient usesthesamesecret keyto decrypt the scrambled text to plain text.Figure. Q1.1Symmetric EncryptionStudythe flowchart,and execute it viathe slow runbuttonon Flowgorthm. Addbreakpointstoallow you to observe the values of the variables at variouspointsof the flowchart.(a)Explain and describethepurposes,input, output, and logicof each module in the flowchart: (i)IntToArray (ii)EncryptPhoneNumber (iii)DecryptPhoneNumber (b)Make postings to the Lecture Group Discussion Forum to discusswith fellow studentsto clarifyyour doubts andto explainyour understanding. Then derive your own solutionto parts (i) and (ii), and justifyyour solution usingrelevant postingswhich you agree or disagree.Failure to justify usingyour postings and others’ postings will incur a penalty.