This is very small content presentation specially for seminar and all. but this topic is very less people known to you.

1. DIGITALSIGNATURE
PreparedBy: Nirav C. Solanki
(130573107011)

2. •Adigitalsignatureordigitalsignatureschemeisamathematicalschemefordemonstratingtheauthenticityofadigitalmessageordocument.
•Avaliddigitalsignaturegivesarecipientreasontobelievethatthemessagewascreatedbyaknownsender,andthatitwasnotalteredintransit.
•Digitalsignaturesarecommonlyusedforsoftwaredistribution,financialtransactions,andinothercaseswhereitisimportanttodetectforgeryortampering.

3. WHY DIGITAL SIGNATURE?
Parameter
Paper
Digital
Authenticity
May be forged
Can not be copied
Integrity
Signature independent of the document
Signature depends on the contents of the document
Non- repudiation
a.Handwriting expert needed
b.Error prone
a.Any computer user
b.Error free

4. DIGITAL SIGNATURE PROVIDES
•Privacy
•Authentication
•Integrity
•Non-repudiation

5. FUNCTIONING OF DIGITAL SIGNATURE
•Keys
•Private Key
•Public Key

6. Encrypt with Public Key
Decrypt with Private Key

7. HASHES FOR DIGITAL SIGNATURES
Insimpleform,ahashisanalgorithm(orsetofsteps) thatyoucanrunapieceofdatathrough(text,afile,etc.)andgetoutanumberthatrepresentstheoriginal.

8. Message Digest
Hash
Message

9. Message Digest
Encrypt with Public Key
Signature
Signature
Append

10. Hash
Decrypt with Private Key
Message Digest
Message Digest

11. AN EMAIL ENCRYPTION EXAMPLE
LetsstartwithTomandSuzie.TheywanttocommunicatesecurelytokeepHitlerfromreadingtheirmessages.Theyaregoingtouseemailencryptiontocommunicate.

12. FirstTom,sendsSuziehispublickey.ThisusuallyhappensautomaticallywhenTomsendsSuzieanormalemailmessage.TheiremailprogramshandlesendingTom’skeyandrecordingitonSuzie’ssideofthings. WhenSuziesendsTomaregularmessage,Tomgetsherkeyaswell.

13. SuzietakesTom’spublickeyandusesittoencryptanimportantmessage.ThensheemailstheencryptedmessagetoTom.

14. Butwait!HitlerinterceptsthemessagebyinfiltratingSuzie’sISPandbreakingintoheremail.HenowhastheencryptedemailmessagethatSuziesenttoTom.HitleralsohasTom’spublickeythatTomsenttoSuzie.However,nomatterwhatHitlerdoeswiththepublickey,hecan’tdecryptthemessage.TheonlythingthatcandecryptthemessageistheprivatekeythatTomkeepssafe.EmailencryptionpreventsHitlerfromreadingthemessage–eventhoughhehasacopyoftheemailthatwastransmittedovertheinternet.

15. WhenTomgetsthemessagefromSuzy,hetakeshisprivatekeyandusesthattodecryptthemessage.HecannowreadSuzie’semail.Itdoesn’tmatterwhoelsegetsacopyoftheemailthatSuziesent.EmailencryptioninsuresthatTomistheonlyonewhocanunlockitaslonghashedoesn’tsharehisprivatekey.IfhewantstoreplytoSuzie,hesimplyusesherpublickeytoencrypthisreplyandsendsitbacktoher.

17. DIGITAL CERTIFICATE TYPICALLY CONTAINS:
•Owner'spublickey
•Owner'sname
•Expirationdateofthepublickey
•Nameoftheissuer(theCAthatissuedtheDigitalCertificate)
•SerialnumberoftheDigitalCertificate
•Digitalsignatureoftheissuer
•ThemostwidelyusedstandardfordigitalcertificatesisX.509.

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19. Thank You…!!!
Have a nice day… 