When
the data is known by the very high authority persons only. Lose of this data
may cause critical damage to the company secret
Diffie Hellman is considered as an example of Key exchange protocol
The shift cipher is sometimes referred to as the Caesar
Cipher
Access control in windows is more flexible than Unix "صح"
Access control in Unix is more flexible than Windows "خطأ"
In Simple security property, the subject
S may read object O only if Classification/ confidentiality(O) is dominance
Classification/ confidentiality(S) "خطأ"
In asymmetric key cryptography, the
private key is known by sender "خطأ"
The value of x for the formula 3 * X mod
17 =7 is 8 "صح"
For matrix inverse existence, the
determinant of a matrix should satisfy the following Det(A) mod N≠0 and GCD(det(A) mod N,
N)=1
Dose 13 has a multiplicative inverse in
mod 26 "خطأ"
Apply the brute force attack on the
captured cipher "GSQTYXIV" to obtain the used key and the plaintext.
Note: Caesar
cipher is used for encryption Key=4 and
Plaintext is Computer
.…… If
the input (011001) to the S-box S2, then the output is 0110
The left circular shift is implemented
based on the round number; in round # 1 …………
is/are shifted One bit
:The input block length in DES is bit 64
The obtained result when the permutation
P=(7 5 6 3 2 4 8 1) is implemented over the text ”10110100” is 00110101
Is used as PRNG in windows and internet
protocols -------------------- RC4
?(In what way does the RSA algorithm
differs from the Data Encryption Standard (DES It uses a
public key for encryption
Each block of plaintext is XORed with an
encrypted counter. The counter is incremented for each subsequent block",
is a
.description of ___________ mode Counter
Assume that p=5, q=7. If e = 23 is
public, then the private key d for RSA 23
----------------------------------------to protect information assets
Information Security
Crypt-analysis is used to
find some insecurity in a cryptographic scheme
A challenge with ------------------------------------------- is the
efficient and secure distribution of keys Symmetric key cryptography
Acts or actions that exploits vulnerability (i.e., an identified
weakness) in controlled system Attack
If we use extended Vigenere cipher (26
English letters and 10 decimal digits) to encrypt “EN 17”
using key word “comp”.
Then, we obtain ----------------------
as a ciphertext. Note that take blank into your account z=25, blank=26, 1=27…...
Hint: Use modular arithmetic.
G2CGJ .a
FCM19 .b
None of these .c
C3GCJ .d
G2CJG .e
Chosen Plaintext Eve can have a
ciphertext corresponding to a sample plaintext which she believes is useful to
figure the Key "صح"
The input of S-box in DES is ………………bits
and the output is …………………bits Input 6 bits and output 4 bits
Lucifer cipher is accepted as DES
modes of operation have been
standardized by NIST for use with symmetric block ciphers such as DES and
__________.AES Five
Which of the following is not a block
cipher operating mode CBF
Assume that p=5, q=7. If e = 17 is
public, then the private key d for RSA 17
Apply the brute force attack on the
captured cipher "Kiskvetlc” to obtain the used key.
Note: Caesar cipher is used for encryption of English alphabetic. Just write
the value of the key in your answer 4
If we use extended Vigenere cipher (26
English letters and 10 decimal digits) to encrypt “COVID19”
using key word “2020AZ”.
Then, we obtain ---------------------- as a ciphertext. Note that Z=25, 0=26,
1=27, 2=28…... Hint: Use modular arithmetic. 4EN8DQ1
SHA-1, SHA-2, and SHA-3 are Hash
functions
If we use Cesar cipher to encrypt “Computer”
using key = 7. Then, we obtain ---------------------- as a ciphertext. Note
that Z=25, 0=26 . JVTWBALY, None of these
The multiplicative inverse of 7 in mod
37 16
Communication Security is defined
as The
protection of communication media, technology and content
trying every possible combination of options of a password Brute force
The
___ and ___ block cipher modes of operation are used for authentication
CBC, CFB
The
Nonce must be a data block that is unique to each execution of the encryption
operation and may be a counter, a timestamp, or a message number TRUE
DES
uses a key generator to generate sixteen 56 round keys FALSE
The
process of converting the ciphertext to plaintext is known as ciphering
or encryption.
a.FALSE
Which two important issues are addressed with public-key
cryptography
Key distribution and Digital
signatures
The
__ method allows the two parties to use a one-time session key.
Diffie-Hellman
technique
used to gain unauthorized access; the intruder sends messages to a computer
with an IP address indicating that the message is coming from a trusted host
(intruder assumes a trusted IP address)
a.None of these
b.Spam
c.Man-in-the-middle
d.Brute force
e.Spoofing
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