# Recent questions tagged cryptography 1 vote
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 __________. $1$ $1/n$ $1/m$ $n/m$
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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
1 vote
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 $\text{ TINESAX / EOAHTFX / HTLTHEY / MAIIAIX / TAPNGDL / OSTNHMX }$ ... $\text{ EOAHTFX / TINESAX / HTLTHEY / MAIIAIX / TAPNGDL / OSTNHMX }$
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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.
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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?
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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.
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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).
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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?
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How to calculate such a value: Please, someone explain because this is not possible on cal….!
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How to calculate Mod of a big number in RSA Like 5 raise to power 13 mod 77
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Please tell me shortcut to calculate d (private key) in RSA Algorithm
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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
1 vote
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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)
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In an RSA system, the public key of given user is e = 31 and n = 3599. The private key of user will be ________
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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
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Decrypt the message "WTAAD" using the Caesar Cipher with key =15 LIPPS HELLO PLLEH DAATW
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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
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How is group theory and cryptography linked?
1 vote
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
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?
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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?
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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?
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Using RSA, choose p = 3 and q = 11, and encrypt “DOG” as one message m.
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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
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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