SOURASHTRA COLLEGE

CRYPTOLOGY

BY L.S.KARNAN II YEAR B.Sc., Maths

Cryptology is the Study of ‘’Secret Writings’’. Modern Cryptology combines the studies of Computer

Science and Mathematics for the purpose of Encoding information to ensure that data is secure.

It comes from the Greek words Kryptos, meaning hidden and Graphen, meaning to write.

Invisible ink is a good example.

CRYPTOLOGY

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Encryption: c = Ee(p)

Decryption: p = Dd(c)

Here p is a block of plaintext,

c is a block of ciphertext,

E is the encryption function, e is the encryption key,

D is the decryption function and d is the decryption key.

CRYPTOGRAPHY:

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MATHSEncryption

NZGSHDecryption

MATHS

Example:

Plain text

Cipher textPlain text

NZGSH

Cipher text

A B C D E……………Y Z

26 25 24 23 22…………... 2 1

1 2 3 4 5……………25 26 FORWARD NUMBER

FORWARD LETTER

BACKWARD NUMBER

M - 14 - N vice - versaA - 26 - ZT - 07 - GH - 19 - SS - 08 - H

B.N F.L

For DecryptionFor Encryption

CODING METHOD :

Cryptography is the art and

science of creating secret

codes.

Cryptanalysis is the art and

science of breaking those

code.

CRYPTANALYSIS:

1.Now-a-days, internet is very insecure therefore cryptology method is followed to safeguard to transmit data.

2.It is used in ATM centre.

3.It is used in World War-II

USES:

-Takes a long time to figure out the code.

-It takes long to create the code.

-OVERALL CRYPTOLOGY IT'S A LONG PROCESS.

LIMITATIONS:

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