Ppt Final Sowmya

8/8/2019 Ppt Final Sowmya

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SOWMYA DYAKAM

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AIM:

The main aim of the dissertation is study and analyzethe online exam system and to provide authenticationusing cryptography.

DIFFERENT TYPES OF AUTHENTICATION TOOLS

ARE:DIGITAL CERTIFICATES ON SMART CARDS:` These are digital files that certify the identity of

individual by seeking access to computer basedinformation.

` Expensive.` Require training.` Require multiple certificates for different sites.

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TOKENS : Another form of authentication used

instead of Password. These require additional

Costs like replacing.

` Multiple tokens are required for multiple devices.

Need to carry them. Do not protect for man-in-

middle attacks.

s/w tokens: require training, deployment should be

done in a completely protected area.

When there is problem with operating system then it

need to reconfigured or installed.

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CHALLENGE RESPONSE:

` Here question will be asked and the user need to

answer.

` Low security in man-in-middle attacks.

` High customer support cost.

` Need to remember multiple answers for multiplequestions.

OUT OF BAND AUTHENTICATION:

` Two factor authentication ( requires two options for

authentication).` Susceptible to man-in-middle attacks. Limited

coverage and low security.

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BIOMETRICS: use of techniques which uniquely

determine human beings.`

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` Very expensive.` Require cost for hardware, support and for maintenance. High

deployment cost.

` Use of finger print authentication has problems with scanning.` It doesnt work if there is problem with the scanner. If there are

any spots, cuts or dust.` Continuous scanning at same place.

USER ID AND PASSWORD:

password is used for protecting and controlling the informationagainst the access of the unauthorized user.

` Least expensive.` No need to carry separate hardware.` No need of extra software.`

Can be changed.` The main factor is that it can be used irrespective of place.

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ATTACKS ON PASSWORDS:

The least technical of the various password-attack techniques consists of

password guessing

If attackers obtain a valid user id and a bit of information about the user, they

can start guessing. Users select passwords they can remember : Birthday,

Mother's maiden name, Spouses name, Childs name, The user id itself

Obtaining valid user ids is often a simple matter, because organizations tend to

use an individual's names in some combination.

Organizations sometimes posts the names of their management team membersand other individuals, sometimes with short biographies, on their Web sites.

People pick common words for their password.

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` Amethod of determining passwords is to use a password-cracking program.

` These programs use a dictionary of words.

` The programs often permit the attacker to create various rules that tell the program how to

combine words to form new possible passwords.

` Rules can also be defined so that the cracking program will substitute special characters for

other characters, or combine words together.

ABRUTE-FORCE

ATT

ACK:- entails the password-cracking program attempting all possible

password combinations.

` The length of the password and the size of the set of possible characters in the password

affects the time a brute-force attack will take.

` A brute-force attack on a password can take place at two levels.

` An attack on a system with the attacker attempting to guess the password at the login prompt

` The attack can be made more difficult by locking the account after a few failed login

attempts.

` An attack against the list of passwords contained in a password file.

` The password file must be maintained securely, so that others may not obtain a copy of it

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Strengths of RIJNDAEL` Daemen and Rijmen have specified Rijndael's advantages based on implementation aspects,

simplicity of design, variable block length and extensions. Rijndael's implementation is veryflexible since it can be used with varying key sizes and block sizes. It is also possible tochange the sequence of some steps in Rijndael without affecting the cipher. The cipher is hasa simple and elegant structure. It does not hide its structure by using complex components.Instead, it benefits from the advantages gained by the use of simple components in a welldefined structure. Rijndael's security is based on the interaction of the cipher's individualcomponents.

` Rijndael is described as having a 'rich algebraic structure' which allows the cipher's security

to be easily assessed in a limited time frame. This is an advantage over more complex designsthat require extensive thinking, searching and 'bit tracing'. Rijndael is consistently a verygood performer in both hardware and software across a wide range of computingenvironments. Its key setup time is excellent, and its key agility is good. Rijndael's very lowmemory requirements make it very well suited for restricted-space environments. There isadditional security in that Rijndael's operations are among the easiest to defend against powerand timing attacks.

` The following scenario has been described to convey Rijndael's resistance to brute forceattacks, "Assuming that one could build a machine that could recover a DES key in a second(i.e., try 255 keys per second), then it would take that machine approximately 149 thousand-billion (149 trillion) years to crack a 128-bitAES key. To put that into perspective, theuniverse is believed to be less than 20 billion years old. It also provides good security againstlinear cryptanalysis, differential cryptanalysis and opportunistic attacks.

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` RIJNDAEL:

` Chosen by NIST based on the security and

efficiency.` it is iterated block cipher.

` Security was main option to choose but ease of

structure was main reason to select.

` Combination of security, performance, efficiency,ease of implementation and flexibility.

` DETAIL:

` As it a iteration block cipher the encryption and

decryption are done based on the iterations of thespecific transformation.



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` Input is 8bit byte array which creates data block.

Cipher key is 8bit byte array.` It operates on various key sizes: 128, 192, 256.

` Sub keys are derived using key schedule.

` Cipher key is expanded to create expanded key.

So that no attacks.` Round key=length of data block * number of

rounds+1.

Process:

Byte sub step followed by shift row then mixcolumns and finally add round key step.



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The official Rijndael web site displays this image to promote understanding of

the Rijndael round transformation



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` Architecture:



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THANK YOU


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