In the following scenario, we will compare the security services that are given by digital signatures (DS) and message authentication codes (MAC). We assume that James can read all messages send from Chan to Badrul and the other way around, too. James has no knowledge of any keys but the public one in the case of DS. State whether and how (i) DS and (ii) MAC protect against each attack. The value auth(x) is calculated with DS and MAC’s algorithm, correspondingly. i) (Message integrity) Chan sends a message x = “Transfer RM200 to Darren” in the clear and also sends auth(x) to Badrul. James intercepts the message and replaces “Darren” with “James”. Will Bob detect this?. ii) (Replay) Chan sends a message x = “Transfer RM200 to James” in the clear and also sends auth(x) to Badrul. James observes the message and signature and sends them 100 times to Badrul. Will Badrul detect this? iii) (Sender Authentication with the cheating third party) James claims that he sent some message x with a valid auth(x) to Badrul, but Chan claims the same. Can Badrul clear the question in either case? iv) (Authentication with Badrul cheating) Badrul claims that he received a message x with a valid signature auth(x) from Chan (e.g., “Transfer RM200 from Chan to Badrul”) but Chan claims she has never sent it. Can Chan clear this question in either case? ASCII TableCharOctHex | CharDecOctHex | CharDecDecOctНехOx20 | @Ox21 | AOx22 | BОх23 | СOx24 | DОх25 | E0046 Ox26 | EOx27 | GОх28 | НОх29 | 1Ox2a i JOx2b | KОх2с | LOx2d | MOx2e | NOx2f | 0Ох30 | POx31 | QOx32 | ROx33 i sОх34 | TOx35 | UOx36 | vOx37 | WОх38 | XOx39 | YОхЗа | ZOx3bОх3с |Ox3d | ]Ox3e |Ox3f |Ox40 |Ox41 | aOx42 | bOx43 | COx44 | dOx45 | eOx46 | fOx47 | gOx48 | hОх49 | iOx4a | jOx4b | kOx4c ||Ox4d | mOx4e | nOx4f | oOx50 | pОх51 | qOx52 |rOx53 | sOx54 itOx55 | uOx56 | vOx57 | wOx58 | xOx59 | yОх5а | zOx5b | {Ox5c ||Ox5d | }Ox5e |Ox5f(sp)3200406401009601400141014201430144014501460147Ox60Ох61Ox62Ох63Ох64Ox65Ох66Ох67Ох68Ox69ОхбаOx6b3334353637383900410042004300440045656667686970710101010201030104010501060107979899100101102103#3&00474041424344454647005000510052005300540055005600577273747576777879011001110112011301140115011610410510610710810911011101500151015201530154015501560157ОхбсOx6dОхбе0117Ox6f4849505152535455006000610062006300640065006600678081828384858687016001610162016301640165016601670120012101220123012401250126012701300131013201330134013501360137112113114115116117118119Ox70071Ox72Ox73Ox74Ox75Ox76Ox77146.5657585960616263007000710072007300740075007688899091929394950170017101720173017401750176120121122123124125126Ox78Ox79Ox7aOx7bOx7cOx7dOx7e>0077

Solution Code(MAC) Message Authentication: MAC is an authentication technique that uses the…

n the following scenario, we will compare the security services that are given by digital signatures (DS) and message authentication codes (MAC). We assume that James can read all messages send from Chan to Badrul and the other way around, too. James has no knowledge of any keys but the public one in the case of DS. State whether and how (i) DS and (ii) MAC protect against each attack. The value auth(x) is calculated with DS and MAC’s algorithm, correspondingly. i) (Message integrity) Chan sends a message x = “Transfer RM200 to Darren” in the clear and also sends auth(x) to Badrul. James intercepts the message and replaces “Darren” with “James”. Will Bob detect this?. ii) (Replay) Chan sends a message x = “Transfer RM200 to James” in the clear and also sends auth(x) to Badrul. James observes the message and signature and sends them 100 times to Badrul. Will Badrul detect this? iii) (Sender Authentication with the cheating third party) James claims that he sent some message x with a valid auth(x) to Badrul, but Chan claims the same. Can Badrul clear the question in either case? iv) (Authentication with Badrul cheating) Badrul claims that he received a message x with a valid signature auth(x) from Chan (e.g., “Transfer RM200 from Chan to Badrul”) but Chan claims she has never sent it. Can Chan clear this question in either case

Computer Networking: A Top-Down Approach (7th Edition)

7th Edition

ISBN:9780133594140

Author:James Kurose, Keith Ross

Publisher:James Kurose, Keith Ross

Chapter1: Computer Networks And The Internet

Section: Chapter Questions

Problem R1RQ: What is the difference between a host and an end system? List several different types of end...

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In the following scenario, we will compare the security services that are given by digital signatures (DS) and message authentication codes (MAC). We assume that James can read all messages send from Chan to Badrul and the other way around, too. James has no knowledge of any keys but the public one in the case of DS. State whether and how (i) DS and (ii) MAC protect against each attack. The value auth(x) is calculated with DS and MAC’s algorithm, correspondingly.

i) (Message integrity) Chan sends a message x = “Transfer RM200 to Darren” in the clear and also sends auth(x) to Badrul. James intercepts the message and replaces “Darren” with “James”. Will Bob detect this?.

ii) (Replay) Chan sends a message x = “Transfer RM200 to James” in the clear and also sends auth(x) to Badrul. James observes the message and signature and sends them 100 times to Badrul. Will Badrul detect this?

iii) (Sender Authentication with the cheating third party) James claims that he sent some message x with a valid auth(x) to Badrul, but Chan claims the same. Can Badrul clear the question in either case?

iv) (Authentication with Badrul cheating) Badrul claims that he received a message x with a valid signature auth(x) from Chan (e.g., “Transfer RM200 from Chan to Badrul”) but Chan claims she has never sent it. Can Chan clear this question in either case?