4901 Course Work

8/6/2019 4901 Course Work

1/19

49014901

GROUP E

SUBMITTED BY

SRINIVAS PAVULURI

PRAVEEN

ATCHYUT

WAQAS


2/19

PAPERPAPER11

USING ENCRYPTIONUSING ENCRYPTION

AUTHENTICATION IN LARGEAUTHENTICATION IN LARGE

NETWORKS OF COMPUTERSNETWORKS OF COMPUTERS

BY

SRINIVAS PAVULURI

PRAVEEN


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Is This Paper Well Organized

The paper given for us mainly discuss about the

authentication and the protocols used for authentication

The format is an IEEE paper but the content on thepaper not that much clear


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INTRODUCTIONINTRODUCTION

As per the upgrading of the technology we need to

mainly concentrate on the security of the communication,

for security we need to mainly concentrate on the

Authentication

Authentication means determining whom you are

talking to before revealing sensitive information

Arbitrary keys are used for encrypt and decrypt the

message between two machines


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WHY WE NEED TO HAVEWHY WE NEED TO HAVE

AUTHENTICATIONAUTHENTICATION

During the communication intruder can hack the

message either he can alter or copy the message. So,

we need to have authentication for the

communication channel

If we use authentication then the channel will be

more secure, In order to access the channel Its

compulsory to have the key

The different security issues are

Email security, IP security, Web security, Firewalls,

Wireless security


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Classification ofAuthenticationClassification ofAuthentication

A two way communication between two machines

which is authenticated either direction

A one way communication where there is no protocolexchange between the sender and the receiver

Authentication will be done by the third party


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Steps of encryption

Encryption Algorithms

Authentication Servers

Means of Encryption

Protocols

MAINSECTIONMAINSECTION


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EncryptionAlgorithmsEncryptionAlgorithms

The two Different types of Algorithms are

Conventional

Public-key encryption


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ConventionalAlgorithmConventionalAlgorithm

For convolution encryption algorithm same key is

used for encryption and decryption

NBSData encryption standard is used as the basic

conventional algorithm


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PublicPublic--key encryptionkey encryption

For public-key encryption two types of keys are

used public key and secrete key

Both the keys are used to for conversion of the clear

text to cipher text or vise versa


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AUTHENTICATIONSERVERSAUTHENTICATIONSERVERS

The authentication server has data base containing

index by names

The purpose of authenticate server is to identify and

deliver the requested secret key


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MEANSOF ENCRYPTIONMEANSOF ENCRYPTION

The format of encryption

X= encryption(Y,key)

The format of decryption

Y=decryption(X,key)


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ProtocolsProtocols

Conventional algorithmIt is a general algorithm which uses

A --> AS: A, B, IA1

AS--> A: {IAI, B, CK, {CK, A}KB} KA

A--->B: {CK, A}KA

B--->A: {IB} cKA--->B: {Is - 1} Ck

There are five messages in the algorithm so we can the no of

messages to three but we need the mutual handshakingA ---> B: {CK, A} KB, {IA2) CKB--->A: {IA2- 1,IB} CK


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With PublicWith Public--Key AlgorithmsKey Algorithms

Any user will have the two keys , public key and secrete keyPublic key is a key which can known by any one where as secret

key is confidential key like banks pin no

A and B is presumed to know the AS's public key, PKAS, which

is used to decrypt the message SKA S is the authentication

server's secret key

AAS A, B

ASA {PKB, B} SKAS

A B {IA, A} PKBB AS B, A

ASB: {PKA, A} SKAS

B A {IA, IB}

A B {IB} PKB


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MultipleAuthenticationServersMultipleAuthenticationServersA and B are under same authentication servers we can follow above

protocols if the A and B are not in same servers

In case of conventional algorithm protocol the requirement is still to

produce an item of the form {CK,A} KB forA to use when making

his first approach to his server ASA asking the server CK of B server

looks for it finds in the another server ASB then ASA asking ASB that

checksum between B and A , Nonce in this way..

ASA---> ASB: CK, B ,A, IA1

Then the ASB replies to the ASA that checksum of a encrpting withthe

key of B and Nonce of A

ASB---> ASA: {CK, A}ICB, IA

In the case of public key algorithm A directly approachesASB

directly ifA knows that server's public key. We assume that A already

has this knowledge if not A lookup in the master server authentication

for the public key of the ASB


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DigitalSignaturesDigitalSignatures

When A sends the message to B may not be confident thatmessage sent by A is same message . To provide integrity

signatures are used which are produced by the certificate

authorities .

Signatures with Conventional Encryption

Conventional algorithm uses the characteristic function which

consists of the clear text message and property function which

computes and generates the characteristic value it is hard to

find another sensible clear text message thatproduces the same characteristic value. Now A send the

message to the AS then requesting signature blockfrom the

authentication server:

A ~ AS: A, {CS} KA


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On the B side when B receives the message from A decrypts the

message and computes the characteristic value . Now sends the

signature block to the AS which

B--> AS: B, {A, CS} KAs

The server decrypts the signature block and returns its

contents to B:

A S -->B: {A, CS} KB

Now B matches the signature value he got and from the server if

it matches it B Confident that the message is from A


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REFERENCESREFERENCES

EBOOKS

Network security by William Stallings

E REFERENCES

Wikipedia.org

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