cryptography deepan fav subject

A SURVEY OF CRYPTOGRAPHIC ALGORITHMS

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ABSTRACT

• When survey a variety of cryptographic algorithms falling into four main

categories:

DES (block cipher), RC4 (stream cipher),

SHA-1(hash) and RSA (public-key cryptography).

• We are using cryptography method in this survey which is related to the security concepts.

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CRYPTOGRAPHY

• Cryptographic algorithms are a means of discreetly conveying secret information between one party and another.

• The plaintext message is encrypted from sender side using a crypto-graphic algorithm and decrypted the plaintext to the receiver side.

• This will encrypt and decrypt by using cipher text which is convert to duplicate message to hide the message from the hacker.

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CRYPTOGRAPHY CONCEPT

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APPROACHES

• It is an systematic approach and it has 3segments contains

> Security attack

> Security mechanism

> Security service

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SECURITY ATTACK

• Any action that compromises the security of information

owned by an organization.

• The attack teamed as two types which is

->Active attack

->Passive attack

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ACTIVE ATTACK

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PASSIVE ATTACK

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SECURITY MECHANISM

• The mechanisms are divided into those that are implemented in a

mechanism.

• It has specific protocol layer, such as TCP or an application-layer

protocol.

• That are not specific to any particular protocol layer or security

service either detect or prevent.

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SECURITY SERVICES

• It is processing service or communication services mainly used for

protected the resources

• It is implemented by security mechanism

* Authentication

* Access control

* Data confidentiality

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CLASSICAL ENCRYPTION TECHNIQUES• Symmetric encryption, also referred to as conventional encryption or single-

key encryption

• It was only type of encryption in use prior to the development of public key

encryption in the 1970s.

• It remains by far the most widely used of the two types of encryption.-Symmetric

-Assymmetric

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SYMMETRIC ALGORITHMS

• Symmetric algorithms are key-based algorithms that use the same key for encryption and decryption.

• The Caesar cipher mentioned & Both block ciphers and stream ciphers fall into this category

• Stream ciphers are symmetric algorithms that operate on plaintext input one bit (or byte) at a time.

• Block ciphers are symmetric algorithms that operate on larger blocks, usually 64 bits in size

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SYMMETRIC CIPHER MODEL

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Public key cryptography

• public-key/two-key/asymmetric cryptography involves the use of two keys: • a public-key, which may be known by anybody,

and can be used to encrypt messages, and verify signatures

• a private-key, known only to the recipient, used to decrypt messages, and sign (create) signatures is Asymmetric

• Because those who encrypt messages or verify signatures cannot decrypt messages or create signatures 14

Public key cryptography

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Data encryption standards (DES)• Most widely used block cipher in world

• Adopted in 1977 by NBS (now NIST)

• Encrypts 64-bit data using 56-bit key has widespread

• It has been considerable controversy over its security

• Y = IP-1(X) = IP-1(IP(M)) (-1 INVERSE)

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RSA• The RSA encryption/decryption algorithms are a type of public

key cryptography named for Ron Rivest, Adi Shamir and Leonard Adleman, who rst presented the algorithm in 1977

• c = me mod n.

• m = cd mod n

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RSA Key generation

Algorithm 3 RSA Key Generation

•1: procedure Get Keys(b) ->Generates keys based on b-bit primes

•2: p; q primes of bit-length b

•3: n p q -> First public key

•4: (p- 1)(q- 1)

•5: e e such that gcd(e; ) = 1 -> Second public key

•6: d (e-1) mod -> Private key

•7: return n; e; d

•8: end procedure

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CONCULSION

• The purpose of this research was to learn about cryptographic algorithms and to

analyze

• The efficiency of the RSA encryption algorithm when implemented with direct

subroutines and in direct languages.

• Future work could include implementing the algorithm in languages that better

allow bit-level manipulation, such as C.

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THANK U

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