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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