DIGITAL CERTIFICATE , DIGITAL SIGNATURE , CRYPTOGRAPHY THIS INFORMATION HELPS STUDENT IN THEIR PROJECT WORK .

1. INTERNET AND E-COMMERCE
TOPIC:- DIGITAL SIGNATURE , DIGITAL CERTIFICATE AND CRYPTOGRAPHY
PRESENTED BY-
LAKSHAY PARASHAR
NEETU ATARE
PRASHANT SINGH KUSHWAH
B.COM {CA} 3RD SEMESTER
PRESENTED TO -
- ASS.PROFF BHARTI MAM

2. TABLE OF CONENT :-
-TITLE’S -
1 MEANING OF DIGITAL SIGNATURE.
2 STEPS OF DIGITAL SIGNATURE.
3 DIGITAL CERTIFICATE.
4 CONTENT OF DIGITAL CERTIFICATE.
5 DIFFERENCE BETWEEN DIGITAL SIGNATURE V/S DIGITAL CERTIFICATE.
6 MEANING OF CRYPTOGRAPHY.
7 WHY WE USE CRTPTOGRAPHY.
8 CLASSIFICATION OF CRYPTOGRAPHY.
9 DIFFERENCE BETWEEN CLASSICAL V/S MODERN CRYPTOGRAPHY.
10 CONCLUSION.

3. MEANING DIGITAL SIGNATURE
A digital signature is a mathematical technique used to
validate the authenticity and integrity of a message,
software or digital document. It's the digital equivalent of a
handwritten signature or stamped seal, but it offers far
more inherent security.
 A digital code which is attached to an electronically
transmitted document to verify its contents and sender’s
identity.

4. STEPS FOLLOWED IN CREATING A
DIGITAL SIGNATURE
• Message digest is computed by applying hash function on the message and then
message digest is encrypted using private key of sender to form the digital
signature.
• Digital signature is then transmitted with the message.
• Receiver decrypts the digital signature using the public key of sender.
• The receiver now has the message digest.
• The receiver can compute the message digest from the message.
• The message digest computed by receiver and the message digest need to be
same for ensuring integrity.

6. DIGITAL CERTIFICATE
• Digital certificate is issued by a trusted third party which proves sender’s
identity to the receiver and receiver’s identity to the sender.
A digital certificate is a certificate issued by a Certificate Authority (CA)
to verify the identity of the certificate holder. The CA issues an encrypted
digital certificate containing the applicant’s public key and a variety of
other identification information. Digital certificate is used to attach public
key with a particular individual or an

7. DIGITAL CERTIFICATE CONTENT
1. NAME OF THE CERTIFICATE HOLDER
2. SERIAL NUMBER WHICH IS USED TO UNIQICKLY IDENTIFIED THE
CERTIFICATE , AN INDIVIDUAL OR AN ENTITY IDENTIFY BY THE
CERTIFICATE.
3. EXPIRATION DATE
4. COPY OF A CETIFICATE HOLDEROR PUBLIC KEY.(USED FOR
DESCRYPTING MESSAGE AND DIGITAL SIGNATURE.
5. DIGITAL SIGNATURE OF THE CERTIFICATE ISSUING AUTHORITY
6. DIGITAL CERTIFICATE IS ALSO SEND WITH THE DIGITAL SIGNATURE
AND MESSAGE

9. Digital certificate vs digital signature

10. WHAT IS CRYPOTOGRAPHY
 CRYPTOGRAPHY IS THE SCIENCE OF USING MATHEMATICS TO
ENCRYPT AND DECRYPT A DATA .
 CRYPTOGRAPHY ENABLES US TO STORE SENSTIVE INFORMATION
OR TRANSMIT IT ACROSS INSECURE NETWORKS SO, IT CAN NOT BE
READ BY ANYONE INSTEAD OF A INTENDED RECIPIENT.

11. WHY WE USE CRYPTOGRAPHY
• FOR ‘ SECRET WRITING ’
• TO ESTABLISH A SHARED SECRET WHEN
OTHER PEOPLE ARE LISTENING.

12. CLASSIFICATION OF
CRYPTOGRAPHY

13. SYMMETRIC KEY CRYPTOGRAPHY
• What are symmetric keys in cryptography?
• In cryptography, a symmetric key is one that is used both to encrypt and
decrypt information. This means that to decrypt information, one must
have the same key that was used to encrypt it.

14. CLASSICAL CRYPTOGRAPHY
• IN The classical cryptography the original data i.e., the plain text is
transformed into the encoded format i.e. cipher text so that we can transmit
this data through insecure communication channels. A data string which
known as key is used to control the transformation of the data from plain
text to cipher text .

15. TRANSPOSITION CIPHER
• .In cryptography, a transposition cipher is a method of encryption which
scrambles the positions of characters (transposition) without changing the
characters themselves
• A simple example for a transposition cipher is columnar transposition cipher
where each character in the plain text is written horizontally with specified
alphabet width.

16. SUBSTITUTION CIPHER
• A substitution cipher merely substitutes different letters, numbers, or other
characters for each character in the original text. The most straightforward
example is a simplistic substitution in which each letter of the alphabet is
represented by a numerical digit, starting with 1 for A.

17. MODERN CRYPTOGRAPHY
• Modern cryptography relies on cryptographic keys, usually a short string of
text, for encoding and decoding messages in combination with cryptographic
algorithms. Based on the type of keys used, cryptography is classified as
either symmetric or asymmetric key cryptography

18. STREAM CIPHER
• A stream cipher is an encryption technique that works byte by byte to
transform plain text into code that's unreadable to anyone without the
proper key. Stream ciphers are linear, so the same key both encrypts and
decrypts message’s . EX- RC4/ARC4/ARCFOUR is a fast, simple
encryption algorithm developed in 1987 to implement byte-by-byte
encryption using 64 or 128 bits long keys. RC4 is widely used in Transport
Layer Security, Secure Sockets Layer, and the IEEE 802.11 WLAN standard

19. BLOCK CIPHER
• A block cipher is a method of encrypting data in blocks to produce cipher
texts using a cryptographic key and algorithm. The block cipher processes
fixed-size blocks simultaneously, as opposed to a stream cipher, which
encrypts data consume one bit at a time consume .
• EG:-

20. DIFFERENCE :-

21. ASYMMATRIC CRYPOTOGRAPHY-
• Asymmetric cryptography, also known as public-key cryptography, is a
process that uses a pair of related keys -- one public key and one private key
-- to encrypt and decrypt a message and protect it from unauthorized access
or use.

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