Assignment title: Information

ThefirstpartoftheMBCisbasedaroundthefollowingscheme: Dear Bob, I am going to send you 1024 puzzles. Each puzzle is a cryptogram whose plaintext starts out with 128 zero bits (16-bytes), followed by a unique 16-bit (2-byte) puzzle number, and then a 64-bit (8-byte) key. The cryptograms have been encrypted using the DES standard with a key whose final 48 bits are zeros. Please pick one cryptogram at random and break it by brute force, trying all 216 keys ending in 48 zeros. You know you have broken it when you find a key that yields a plaintext starting with 128 zero bits. After breaking the cryptogram, extract the 64-bit key and use it as our shared key. As your first message send me back the puzzle number in plaintext, so I know which key you are going to use. Yours sincerely, Alice Part1: ImplementMerkle’sPuzzles YoushouldimplementtheaboveschemeinJava.Yourimplementationshouldbestructuredas youseefit,butshouldcontainthefollowingfunctionality. Question1:PuzzleGeneration:FirstlyyoushouldwritecodethatAlicecouldusetogenerate 1024 random puzzles. Once the puzzles have been generated, you should encrypt each of the puzzlesusingadifferentDESkey(endingin48zeros!). Question 2: PuzzleStorage:Onceyouhaveencryptedthepuzzlesyoushouldwritethemtoafile.Todothis, youcanrepresenttheencryptedpuzzlesi nASCII.Eachencryptedpuzzleshouldbewrittento itsownline.AnexamplepuzzlefileJTQSPWJEFE. Question 3: Puzzle Cracking: Next, you should implement functionality that allows Bob to readintheencryptedmessages. Yourcodeshouldthenchoosearandommessageandcrackit, bytryingall216 keys. Question4: Keylookup: Finally,implementfunctionalitythatallowsAlicetolookupthekey thatcorrespondstoagivenpuzzlenumber. Thisshouldbefairlystraightforwardsifyouhave usedagoodimplementationstructure. Part2: DemonstrateMerkle’sPuzzlesWorking Question 5: DemonstrateSuccessfulKeyExchange: Youshouldextend thecodeyou havewrittenwithamainclassthat demonstratesthatAlice andBobcanshareasecretkeyandcommunicateusingit. Forexample,yourprogramshould generateaseriesofpuzzlesandstoretheminafile. Yourprogramshouldthenreadinthepuzzles andcrackoneofthem. Oncecracked,BobshouldthensendamessagetoAlicewiththepuzzle number(thismayjustinvolvereturningapuzzlenumberandpassingittoanotherfunction). Finally,AliceshouldsendanencryptedmessagetoBobusingthekeythatcorrespondstothe puzzle number. Bob should be able to successfully decrypt the message. Please note: this part mainly involves calling your previously implemented functions and printing certain information to the screen at the relevant places.Part 3: Programming Style and Documentation Question 6: You should use an appropriate class structure for capturing the above scheme. You should alsousesuitablevariablenames,methodsandcomments. Finally,youshouldincludesuitable JavaDocforallyourmethodsandclasses. HintsandTips "Javafilenamed“CryptoLib.java”.Thisfilecontainsanumberofhelpermethodsthatyoumay wanttouseforworkingwithbytearraysinJava.Inparticularitcontains: • methods for converting small integers (up to 65, 535) to byte arrays and back. • methods for converting byte arrays into SecretKey’s that can be used with the Java DES Library explored in the labs. • methods for converting byte arrays (e.g. keys) into strings (base 64) and back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mOEUIBUEJČFSFOULFZTDBOBMMCF VTFE UP TVDDFTTGVMMZ DSBDL B QV[[MF 5IJT JT EVF UP B OVNCFS PG CJUT XJUIJO B %&4 LFZ CFJOH VTFE BT iQBSJUZwCJUT5IFTFCJUTBSFFTTFOUJBMMZOPUVTFEXJUIJOUIFFČFDUJWFCJULFZ 'JOBMMZ UIF MJCSBSZ DBMM DJQIFSEP'JOBM GSPN MBC %&4 XJMM UISPX B #BE1BEEJOH&YDFQUJPO XIFO HJWFOBOJMMGPSNBUUFELFZ:PVTIPVMEUBLFUIJTFYDFQUJPOBTSFQSFTFOUJOHBLFZCFJOHJODPSSFDU Submission You should submit all your source code files along with a README file that provides informationonhowtorunyourprogramalongwithanyotherinformationyouwantthemarkerto know.