Digital Signiture

A SEMINAR ON

PRESENTED BY :

•VikeshBawane

• Abinesh Tandra

•Venkatesh Asampelli

• Shiv Prakash ReddyH. O. D.

Mrs. S.S. Bhaskarwar

GUIDED BY :

Mrs. Priyanka Singh

INCHARGE:

Mrs. Priyanka Balki

WHAT IS CRYPTOGRAPHY ?

Science of using mathematics to encrypt and decrypt data .

Science of securing data .

KEYS :

Value that works with a cryptographic algorithm to produce a specific cipher text

There are two keys :Private key

Public key

ENCRYPTIONEncryption is the

process of feeding plaintext and key into a function and getting cipher-text output

Cipher-text is “garbage” unless decrypted

© Yingjiu Li 2007 4

EncryptionFunction

Plaintext

© Yingjiu Li 2007 5

DECRYPTIONDecryption is the

process of feeding cipher-text and a key into another function and getting original plaintext output

DecryptionFunction

Plaintext

What is Digital Signature?• Hash value of a message when

encrypted with the private key of a person is his digital signature on that e-Document– Digital Signature of a person

therefore varies from document to document thus ensuring authenticity of each word of that document.

– As the private key of the signer is known, anybody can verify the message and the digital signature

•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

Concepts

• A 1024 bits number is a very big number much bigger than the total number of electrons in whole world.

• Trillions of Trillions of pairs of numbers exist in this range with each pair having following property– A message encrypted with one element of the

pair can be decrypted ONLY by the other element of the same pair

• Two numbers of a pair are called keys, the Public Key & the Private Key. User himself generates his own key pair on his computer

• Any message irrespective of its length can be compressed or abridged uniquely into a smaller length message called the Digest or the Hash.

• Smallest change in the message will change the Hash value

Digital Signature Digital Signature

Hash Hash Function Function

MessageMessage

SignatureSignature

Public KeyPublic Key EncryptionEncryption

DigestDigest

MessaMessagege

DecryptionDecryption

Private KeyPrivate Key

ExpectedExpectedDigestDigest

ActualActualDigestDigest

SignerSigner ReceiverReceiverChannChannelel

DigestDigestAlgorithmAlgorithm

Modules

Assign Digital signature Encryption & Decryption

to document of data using RSA

algorithm:- 1.Key

generation

2.Encryption

3.Decryption

Challenges and OpportunitiesOpportunities:-Imposters: by minimizing the risk of

dealing with imposters or persons who attempt to escape responsibility by claiming to have been impersonated;

Message Integrity: by minimizing the risk of undetected message tampering and forgery, and of false claims that a message was altered after it was sent;

Formal legal Requirements: by strengthening the view that legal requirements of form, such as writing, signature, and an original document, are satisfied, since digital signatures are functionally on a par with, or superior to paper forms; and

CHALLENGES AND OPPORTUNITIES CONT’D

Opportunities:-Open Systems: by retaining a high

degree of information security, even for information sent over open, insecure, but inexpensive and widely used channels.

Advantages Data integrity

Authentication of Identities

Non-repudiation

date and time stamp

speed and accuracy

APPLICATIONTo certify a document with digital

signature.

For securing data transaction between the parties.

It will use in a large scale organization for mutual

agreement.

To transmit secure data.