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Digital signature


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Introduction to digital signature and its applications.

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Digital signature

  1. 1. Submitted to:- Prof.Samta Jain Submitted By:- Navneet Prakash Preeti Yadav Aakanksha Tomar
  2. 2. ●“A Digital Signature is an Electronic Signature .”
  3. 3. To authenticate the identity of the sender of a message The signer of a document, and To ensure that the original content of the message or document that has been signed is unchanged
  4. 4. ●Only the owner can create the digital signature, hence it can be used to verify who created a message ●Generally don't sign the whole message (doubling the size of information exchanged), but just a digest or hash of the message ●A hash function takes the message, and produces a fixed size (typically 64 to 512 bits) value dependent on the message
  5. 5. ●Digital Signature - a data string which associates a message with some originating entity ●When using a digital signature, the data itself is not encrypted, but a hash of the data is encrypted with a private key. A hash (also known as a digest) is a unique, fixed-length mathematical value that is determined by the content of the message
  6. 6. ●In 1976,Whitfield Diffie and Martin Hellman first described the Digital Signature. ●In 1984, Shafi Goldwasser, Silvio Micali, and Ronald Rivest became the first to define the security requirements of digital signature schemes.
  7. 7. Caesar Cipher The shift is linear and equidistributed 3 changes I agree lcdjuhhKey Cipher The shift is linear (cyclic) 269 k.n.gupta 62 mewam3rzjba i+3=l Space=c [+3] k+2= m (dot)=e [+6] n=w [+9]
  8. 8. I agree efcc61c1c03db8d8ea8569545c073c814a0ed 755My place of birth is at Gwalior. fe1188eecd44ee23e13c4b6655edc8cd5cdb 6f25I am 20 years old. 0e6d7d56c4520756f59235b6ae981cdb5f982 0a0I am an Engineer. ea0ae29b3b2c20fc018aaca45c3746a057b8 93e7 I am a Engineer. 01f1d8abd9c2e6130870842055d97d315dff1 ea3 ●These are digital signatures of same person on different documents ●Digital Signatures are numbers ●Same Length – 40 digits ●They are document content
  9. 9. ●Message Message + signature Hash SIGN hash With Sender’s Private key Signed Message Sent thru’ Internet Message + Signatur e Calculate d Hash COMPARE Ha sh Decrypt Signature With Sender’s Public Key Sende r Receive r if OK Signatures verified
  10. 10. ●A digital certificate is an electronic “document” ●or computer generated record that officially links together the subscriber’s identification with the corresponding public key. ●The certificate is digitally signed by the issuing Certification Authority (CA ) to ensure the certificate’s authenticity so that anyone in possession of the CA’s public key can verify the legitimacy of the certificate
  11. 11. ●Certificate authorities (CA’s) will provide a requestor with someone’s public key contained in a certificate. Information in the certificate will identify the public key’s owner, and provide the name of the CA who validated the identity and signed the identity to public key binding. In this way it is possible to see that a certificate serves as a kind of protective “container” for the public key, protecting the integrity of its binding to an owner and authenticating both the binding and identity via the reputation (and trust) of the signing CA.
  12. 12. Private Key – Used for making digital signature Public Key – Used to verify the digital signature
  13. 13. ●If the sender wishes to prove to a recipient that he or she is the source oftheinformation, the sender uses his or her private key to digitally sign a message (adigital signature).
  14. 14. ●The receiver of a digitally signed message uses the sender’s public key to verify the signature so that the receiver knows that the person controlling the private key corresponding to the public key sent the information, and that the received information has not been altered since it was signed.
  15. 15. ●A key generation algorithm that selects a private key uniformly at random from a set of possible private keys. The algorithm outputs the private key and a corresponding public key. ●A signing algorithm which, given a message and a private key, produces a signature. ●A signature verifying algorithm which given a message, public key and a signature, either accepts or rejects.
  16. 16. ●To provide Authenticity, Integrity and Non-repudiation to electronic documents ●To use the Internet as the safe and secure medium for e-Commerce.
  17. 17. ●Authentication :-Although messages may often include information about the entity sending a message, that information may not be accurate. Digital signatures can be used to authenticate the source of messages. When ownership of a digital signature secret key is bound to a specific user, a valid signature shows that the message was sent by that user. The importance of high confidence in sender authenticity is especially obvious in a financial
  18. 18. 1.Integrity :-In many scenarios, the sender and receiver of a message may have a need for confidence that the message has not been altered during transmission. Although encryption hides the contents of a message, it may be possible to change an encrypted message
  19. 19. ●Putting the private key on a smart card ●Using smart card readers with a separate keyboard ●Using digital signatures only with trusted applications
  20. 20. ●Saving Of Time ●Cost Reduction ●Increased Security ●Compliance
  21. 21. ●Digital signatures are commonly used for software distribution, financial transactions, and in other cases where it is important to detect forgery and tampering.
  22. 22. ●Hence We are conclude that to use digital signature we can secure our information by Private and public key. ● A digital signature is an electronic signature that can be used to authenticate the identity of the sender of a message or the signer of a document,
  23. 23. Thanks You