PRESENTED BY- JITENDRA YADAV

G-5 DM-1214068

DIGITAL SIGNATURE

Why do we need Digital Signature ???

• A MAC can provide message integrity and message authentication.

• MAC has a drawback. It needs asymmetric key that must be establish between the sender and the receiver.

• A digital signature on the other hand, can use a pair of asymmetric key (one public and a private key).

What is Digital signature ???

• A digital signature is a mathematical scheme for demonstrating the authenticity of a digital message or document.

• A valid digital signature gives a recipient reason to believe that the message was created by a known sender , and was not altered in transit.

• Digital signatures are commonly used for software distribution, financial transactions ,and in cases where it is important to detect forgery and tampering.

Various methods of employing Digital Signature:-

• Using asymmetric ±key Cipher. • Using Keyed Hash function.

Public key Cryptography

• Public-key cryptography involves the use of asymmetric key algorithms.

• Asymmetric key algorithms used to create a mathematically related key pair.

• A secret Private key and a published Public key. • Protects the confidentiality and integrity of a

message. • The message is Encrypted using the Public key,

which can only be Decrypted using the Private key.

Digital Signature using Keyed Hash Function:

• To preserve the integrity of a message. • The message is passed through an algorithm, called hash

function. • T he electronics/equivalent of the document and finger print

pair is the message and digest pair. • The hashed function creates a compressed image of the

message that can be used as a finger print. • For compatibility. • For integrity. • For efficiency.

Cryptographic protocol

Cryptographic protocol or Encryption protocol • It Is an abstract or concrete protocol performing a security-

related function and applies cryptographic methods. A cryptographic protocol usually incorporates at least some of these aspects:

• Key agreement or establishment. • Entity authentication. • Symmetric encryption and message authentication material

construction. • Secured application-level data transport. • Non-repudiation methods.

Uses of digital signatures

1 .Authentication. 2. Integrity .Additional security precautions:- 1. Putting the private key on a smart card.2. Using smart card readers with a separate

keyboard.3. Other smart card designs.4. Using digital

signatures only with trusted applications.

FUTURE SCENARIO

• Digital encryption of data is useful during storage and retrieval of medical history of patients involve dine-Health programs.

• The growth of e-commerce and the recent enactment of the Electronic Signatures in Global and National Commerce Act (E-Sign Act)has opened a new frontier.

• With this constant development key management is becoming an issue.

• Advancements in Hot Java and Java Plug in based technologies will maintain fluidity and flexibility in key management.