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Recent questions tagged cryptography

1 vote
4 answers
1
If $h$ is chosen from a universal collection of hash functions and is used to hash $n$ keys into a table of size $m$, where $n \leq m$, the expected number of collisions involving a particular key $x$ is less than __________. $1$ $1/n$ $1/m$ $n/m$
asked Mar 24 in DS jothee 177 views
2 votes
2 answers
2
Avalanche effect in cryptography refers Large changes in cipher text when the keyword is changed minimally Large changes in cipher text when the plain text is changed Large Impact of keyword change to length of the cipher text None of the above
asked Jan 13 in Computer Networks Satbir 490 views
1 vote
2 answers
3
In a columnar transportation cipher, the plain text is the tomato is a plant in the night shade family , keyword is $\text{TOMATO}$ . The cipher text is $\text{ TINESAX / EOAHTFX / HTLTHEY / MAIIAIX / TAPNGDL / OSTNHMX }$ ... $\text{ EOAHTFX / TINESAX / HTLTHEY / MAIIAIX / TAPNGDL / OSTNHMX }$
asked Jan 13 in Computer Networks Satbir 576 views
0 votes
1 answer
4
A math class has 25 students. Assuming that all of the students were born in the first half of the year—between January 1st and June 30th— what is the probability that at least two students have the same birthday? Assume that nobody was born on leap day, so there are 181 possible birthdays.
asked Mar 19, 2019 in Computer Networks ajaysoni1924 132 views
0 votes
0 answers
5
33. Two users can establish a shared secret key using the Diffie-Hellman algorithm, even if they have never met, share no secrets, and have no certificates (a) Explain how this algorithm is susceptible to a man-in-the-middle attack. (b) How would this susceptibility change if n or g were secret?
asked Mar 19, 2019 in Computer Networks ajaysoni1924 106 views
0 votes
1 answer
6
The Diffie-Hellman key exchange is being used to establish a secret key between Alice and Bob. Alice sends Bob (227, 5, 82). Bob responds with (125). Alice’s secret number, x, is 12, and Bob’s secret number, y, is 3. Show how Alice and Bob compute the secret key.
asked Mar 19, 2019 in Computer Networks ajaysoni1924 263 views
0 votes
0 answers
7
Alice wants to communicate with Bob, using public-key cryptography. She establishes a connection to someone she hopes is Bob. She asks him for his public key and he sends it to her in plaintext along with an X.509 certificate signed by the root CA. Alice already has the public key ... is talking to Bob? Assume that Bob does not care who he is talking to (e.g., Bob is some kind of public service).
asked Mar 19, 2019 in Computer Networks ajaysoni1924 75 views
0 votes
1 answer
8
If 356 + 123 = 512 .Then what is the value of 653 + 321? 1.215 2.974 3.1004 4.1304 How to solve these type questions?
asked Jan 27, 2019 in Numerical Ability screddy1313 335 views
0 votes
1 answer
9
How to calculate such a value: Please, someone explain because this is not possible on cal….!
asked Jan 26, 2019 in Computer Networks Nandkishor3939 129 views
0 votes
1 answer
10
How to calculate Mod of a big number in RSA Like 5 raise to power 13 mod 77
asked Dec 10, 2018 in Computer Networks Fida 405 views
0 votes
0 answers
11
0 votes
1 answer
12
Using RSA key crypto system with a = 1, b = 2 etc; value for encryption if prime value are p = 7 and q = 11, the legal value for secret key is . a)69 b)49 c)49 d)119
asked Oct 12, 2018 in Computer Networks Shivangi Parashar 2 446 views
1 vote
1 answer
13
0 votes
0 answers
14
Are the following topics there in Syllabus? Digital Signatures Elgamal Digital Signature Scheme Schnorr Digital Signature Scheme Message Authentication Codes Data Encryption Standard (DES) Advanced Encryption Standard (AES) Triple DES Elliptic Curve Cryptography Secure Hash Algorithm (SHA) Message Authentication Codes(MAC)
asked Aug 5, 2018 in Computer Networks Balaji Jegan 226 views
0 votes
1 answer
16
Match the following symmetric block ciphers with corresponding block and key sizes: List - I List -II a DES i block size 64 and key size ranges between 32 and 448 b IDEA ii block size 64 and key size 64 c BLOW FISH iii block size 128 and key sizes 128, 192, 256 d AES iv block size 64 and key size 128 ... ; c-i; d-iii a-ii; b-iv; c-i; d-iii a-ii; b-iv; c-iii; d-|i a-iv; b-ii; c-iii; d-i
asked Jul 13, 2018 in Computer Networks Pooja Khatri 708 views
0 votes
4 answers
17
Decrypt the message "WTAAD" using the Caesar Cipher with key =15 LIPPS HELLO PLLEH DAATW
asked Jul 13, 2018 in Others Pooja Khatri 1.8k views
0 votes
2 answers
18
Encrypt the Message "HELLO MY DEARZ" using Transposition Cipher with $Key \begin{cases} \text{Plain Text} & 2 4 3 1 \\ \text{Cipher Text} &1 2 3 4 \end{cases}$ HLLEO YM AEDRZ EHOLL ZYM RAED ELHL MDOY AZER ELHL DOMY ZAER
asked Jul 13, 2018 in Computer Networks Pooja Khatri 2.1k views
0 votes
0 answers
19
How is group theory and cryptography linked?
asked May 2, 2018 in Others Sri 99 views
1 vote
4 answers
20
Which one of the following algorithm is not used in asymmetric key cryptography? RSA Algorithm Gillie-Hellman Algorithm Electronic Code Book Algorithm None of the above
asked Apr 22, 2018 in Computer Networks Arjun 2.5k views
2 votes
0 answers
21
In RSA Algorithm, we have public key(e,n) and private key(d,n). Sender side we encrypt plain text P as an integer between 0 and n-1 as follows: $P^{e}modn$ and send it. At receiver side, we do the following: $(P^{e}modn)^{d}modn = P^{ed}modn$ ... encrypting the message P we are taking it as as integer between 0 and n-1. So, the P may not be coprime to n. Then how does the algorithm work?
asked Jan 12, 2018 in Computer Networks Ashish Sharma 3 610 views
0 votes
1 answer
22
Consider the following statements with respect to digital signatures: S1: Digital signature ensures authenticity of the sender but not integrity of the message. S2: A single secret key can be used by the sender to sign multiple documents for multiple receiver. S3: Using a ... key. S4: Both RSA cryptosystem and RSA digital signature scheme uses same set of keys. Which of the following is true?
asked Dec 3, 2017 in Computer Networks Appu B 292 views
0 votes
1 answer
23
You generate a perfectly random key K. You send two messages, M1 and M2, encrypted with K (C1 = K xor M1 and C2 = K xor M2). Does sending C2 leak information about M1 and M2?
asked Dec 2, 2017 in Computer Networks vijay_jr 107 views
2 votes
1 answer
24
Using RSA, choose p = 3 and q = 11, and encrypt “DOG” as one message m.
asked Jul 4, 2017 in Computer Networks reena_kandari 216 views
37 votes
3 answers
25
A sender $S$ sends a message $m$ to receiver $R$, which is digitally signed by $S$ with its private key. In this scenario, one or more of the following security violations can take place. $S$ can launch a birthday attack to replace $m$ with a fraudulent ... replace $m$ with a fraudulent message Which of the following are possible security violations? I and II only I only II only II and III only
asked Feb 14, 2017 in Computer Networks Arjun 6.5k views
3 votes
2 answers
28
The plain text message $BAHI$ encrypted with $RSA$ algorithm using $e = 3, d = 7$ and $n = 33$ and the characters of the message are encoded using the values $00$ to $25$ for letters A to Z. Suppose character by character encryption was implemented. Then, the Cipher Text message is _____. ABHI HAQC IHBA BHQC
asked Oct 1, 2016 in Computer Networks makhdoom ghaya 2.3k views
0 votes
1 answer
29
what is the difference between public key and private key ?
asked Sep 1, 2016 in Computer Networks Karthik Akula 384 views
4 votes
1 answer
30
Find the false statement: In Modern Cryptography, symmetric key algorithms use same key both for Encryption and Decryption. The symmetric cipher DES (Data Encryption Standard) was widely used in the industry for security product. The AES (Advanced Encryption Standard) ... variable key lengths of size 56 bits and 124 bits. Public key algorithms use two different keys for Encryption and Decryption
asked Jul 28, 2016 in Computer Networks jothee 814 views
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