slides

1. DIGITAL SIGNATURE

2. CONTENTS
Introduction
Motivation
Howdoes it work?
Application
Advantages
Disadvantages
Conclusion
Reference
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3. INTRODUCTION
A digital signature is a mathematical scheme that is used to
authenticate the sender of an electronic document .
A digital signature is nothing but an attachment to any
piece of electronic information, which represents the
content of the document and the identity of the owner of
that document uniquely
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4. 4
Motivation
To provide Authenticity, Integrity and Non-repudiation to electronic
documents.
To use the Internet as the safe and secure medium for e-Commerce
and e-Governance

5. Basic requirements
Private Key
The private key is one which is accessible only to the
signer. It is used to generate the digital signature which is
then attached to the message.
Public Key
The public key is made available to all those who receive
the signed messages from the sender. It is used for
verification of the received message
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6. Digital certificate
A subscriber of the private key and public key pair makes
the public key available to all those who are intended to
receive the signed messages from the subscriber.[1]
But in case of any dispute between the two sides, there
must be some entity with the receiver which will allow the
receiver of the message to prove that the message was sent
by the subscriber of the key pair. This can be done with the
Digital Signature Certificate.[1]
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7. 7
Digital signature algo

8. How does it work?

9. Message digests
Original number is 7391743
Operation result
Multiply 7 by 3 21
Discard first digit 1
Multiply 1 by 9 9
Multiply 9 by 1 9
Multiply 9 by 7 63
Discard first digit 3
Multiply 3 by 4 12
Discard first digit 2
Multiply 2 by 3 6
Message digest is 6 9

10. Application
Electronic Mail
Data storage
Electronic funds transfer
Software Distribution
Smart Cards
ISDN
Time Stamped Signature
Blind Signatures
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11. Authentication: Identification of the person that signs.
Integrity of data: Every change will be detected.
Non repudiation: Because the author cannot
be denied of his work (he created and sent).
Imposter prevention: Elimination of possibility of committing
fraud by an imposter
Advantages

12. Expiry: In this era of fast technological advancements, many of
these tech products have a short shelf life.
Certificates: In order to effectively use digital signatures, both
senders and recipients may have to buy digital certificates.
Software: To work with digital certificates, senders and recipients
have to buy verification software at a cost.
Disadvantages

13. CONCLUSION
Digital signatures are difficult to understand. Digital
signatures will be championed by many players that the
public distrusts, including national security agencies, law
enforcement agencies, and consumer marketing
companies.
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14. Reference
s
http://en.wikipedia.org/wiki/
Applied Cryptography by Bruce Schneider; 10thAnniversary
edition
FIPS PUB 186-3; FEDERAL INFORMATION
PROCESSING STANDARDS PUBLICATION

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