Hash Problem

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PROBLEM 1
Solution:
A) Now suppose, the two partners are X and Y. X want to send a message to Y. Both X and Y shares the same secret key. To encrypt the message X XORs her message with the shared secret key. To decrypt the message Y also XORs the message with his (the same) secret key.

Now take an example:
Key = 0011
X’s message = 0101
X’s message XORed with the key: 0011 XOR 0101 = 0110
What Y Receives = 0110
Y applies the secret key again to get the original message: 0110 XOR 0011 = 0101

B) Ans-True

C) A cryptographic hash function is a transformation that takes an input or message and returns a fixed size string, which is called the hash value. In Hashing Algorithm, the key in public key encryption is based on hash value. The hash value is a summary of the original value. The important thing about a hash value is that it is nearly impossible to derive the original input number without knowing the data used to create the hash value

Input Number
A 128-bit number has a possible 2128 combinations.

Hashing Algorithm
Input XOR 128

Hash Value
2128 XOR 128

Hash value consists of different combinations and it is not easy to break the value. So that Hashing Algorithm is appropriate for cryptography.

D) Ans-A
Non-Repudiation is one of the main issues of network security. It is used to enable the two parties of a communication to authenticate the communication, such as when a message was sent, when it was received who sent it, and who received it. Encryption is used to secure either data files or network transmissions. But it cannot verify when events happened. Integrity and Confidentiality cannot be used to verify that a message was sent or received.

PROBLEM 2
Solution:
A) Ans-B,C
The following two methods are not used to min...

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...tocol, a standardized way that a mobile phone talks to a server installed in the mobile phone network.

B) Ans- B
The 802.1x standard enhances wireless security by incorporating authentication of the user. In 802.1x, the user must enter a password to access the network. This means that if the wireless client is being used by an unauthorized user, the password requirement will keep the unauthorized user

C) Ans- C
Wi-Fi is the term used for 802.11b product.

D) Ans-B
An initialization vector is a fixed size input to a cryptographic primitive. It is an arbitrary number that can be used along with a secret key for data encryption. The use of an initialization prevents repetition in data encryption, making it more difficult for a hacker using a dictionary attack to find patterns and break a cipher.

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