assigment4

1. a.

i. Apolicytoallowreportingtoallowtheutilitytoreadinformationfromthemeter

ii. Apolicytoallowtheutilitytosendcommandstothemetertoshutoffpower

iii. Apolicytoallowspecificconsumerdevicestoreadthepriceofpowerb. Theutilityhasanincentivetoonlyallowthemselvestoreadandcontrolthe

meterduetocomplaintsfromcustomersandpossibleNERCviolation.Idon'tthinkthecustomerhasahugeincentivetoonlyallowspecificdevicestotalkthemeter.IthinkthissomethingthatneedtobemanagedbyNERC.

c. ItseemslikeyouwouldwanttoimplementsomekindofPKIandusedthatthat.MaybeuseaTLStunneltopassinformationbetweenthemeterthecontrolcenter.Accesstothemeterisusehttpsandmaybeapassword.

2. a. TheHMACisgoingtocomputationallylessintensive.Thismaybeimportant

forthisapplicationwiththelowlatencyrequirements.ThedownsideistheHMACrequiresasharedsecretwhileadigitalsignaturedoesnotrequireit.

b. Whenwemovetomorethantwodevicewereallyneedtousedigitalsignatureifwewanttobeabletodistinguishbetweeneachdevice.SincetheHMACuseasharedsecretthatwouldbesharedbetweenalldevicesandsoyoucannotuseittoauthenticatethedifferentdevices.

3. a. AfalsenegativeiswhenthereissomethingtheIDSshouldhavedetectedthat

itdidnot.thenegativedetectionwasfalse.IthinktheproblemhereisselfevidentbutiftheIDSisnotdetectinganissue.Itisnotdoingitjobandyounowhavesomekindofintrusioninyoursystem.

b. AfalsepositiveiswhenthereissomethingtheIDSdetectedthatisshouldhavenotdetected.Thepositivedetectionwasfalse.TheissuehereisyounowhavetoinvestigatethepositivedetectionsandthemoreoftheseyougetthelesslikelyyouareinvestigateadetectionandthelessusefultheIDSis

c. ThehostbasedIDSgivesyoumorevisibilityintothesystemitisinstalledonbutconversely.Youarelimitedtoonlygetinformationfromthehost.WithanetworkbasedIDS,youcangetamorecompletenetworkandbeabletoausethattodothingsyoucannotdowithahostbasedIDS.

4. Yes,thereareafewwaysthatcrossmymindforhowtocrosstheairgap.Aninfectedthumbdriveseemslikeitwouldcrossthegameeasily.Anotherwaywouldbetohaveaninfectedlaptoppluggedintotheairgappednetwork.Maybesomeoneloadsacompromisedconfigurationontodevicepluggedintoairgappednetwork.

5. AES6. Hashfunction,Symmetrickeycipher,Keyexchangecipher7. rootkits