Digital signatures provide authentication of digital messages and documents using asymmetric cryptography. A digital signature is generated using a private key and can be verified by anyone using the corresponding public key. This allows the recipient to confirm the identity of the sender and verify that the message was not altered during transmission. Digital signatures are commonly used for software distribution, financial transactions, and other situations where detecting forgery and tampering is important. The document discusses how digital signatures work using both asymmetric key encryption and keyed hash functions.

1. PRESENTED BYJITENDRA YADAV
G-5 DM-1214068

2. 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).

3. 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.

4. Various methods of employing
Digital Signature:• Using asymmetric ±key Cipher.
• Using Keyed Hash function.

5. 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.

6. 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.

7. 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.

8. 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.

9. FUTURE SCENARIO
• Digital encryption of data is useful during storage and
retrieval of medical history of patients involve dineHealth 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.