1.
_____________________ defines what size of plain text should be encrypted in each step of algorithm.
Correct Answer
A. Algorithm types
Explanation
The correct answer is "Algorithm types." Algorithm types determine what size of plain text should be encrypted in each step of the algorithm. This choice determines the overall structure and functionality of the encryption process, whether it is a stream cipher or a block cipher. The algorithm type is crucial in determining the encryption strength and efficiency of the encryption algorithm.
2.
______________ is a technique of ensuring that the cipher text gives no clue about original plain text.
Correct Answer
B. Confusion
Explanation
Confusion is a technique used in cryptography to ensure that the cipher text provides no information or clues about the original plain text. It achieves this by making the relationship between the plain text and the cipher text as complex and difficult to decipher as possible. By introducing confusion, the encryption process becomes more secure, as it becomes harder for an attacker to determine any patterns or relationships between the original message and the encrypted version.
3.
_______________ is simply used to make each message unique.
Correct Answer
D. Initialization Vector
Explanation
An Initialization Vector (IV) is used to make each message unique in encryption algorithms. It is a random value that is combined with the encryption key to start the encryption process. The IV ensures that even if the same message is encrypted multiple times, the resulting ciphertext will be different each time, adding an extra layer of security.
4.
Which of these is an algorithm mode?
Correct Answer
B. Cipher block chaining
Explanation
Cipher block chaining (CBC) is a mode of operation for block ciphers. It involves dividing the plaintext into blocks and then encrypting each block using the previous ciphertext block as an input to the encryption algorithm. This creates a chain of blocks, where each block depends on the encryption of the previous block. CBC is widely used in secure communication protocols and provides confidentiality and integrity for the transmitted data.
5.
DES has how many rounds?
Correct Answer
B. 16
Explanation
DES (Data Encryption Standard) has 16 rounds. Each round of DES involves several steps, including permutation, substitution, and XOR operations, which collectively provide strong encryption. The 16 rounds ensure that the data is thoroughly scrambled and makes it difficult for attackers to decrypt the encrypted message without the correct key. This level of complexity and the high number of rounds contribute to the security and effectiveness of DES as a symmetric encryption algorithm.
6.
IP stands for what in DES?
Correct Answer
C. Initial Permutation
Explanation
In the context of DES (Data Encryption Standard), IP stands for Initial Permutation. Initial Permutation refers to the first step in the DES algorithm, where the positions of the bits in the input block are rearranged according to a specific permutation table. This permutation is done to provide confusion and diffusion properties in the encryption process. The Initial Permutation step ensures that the input data is thoroughly mixed and prepared for further encryption rounds.
7.
In the 16 rounds of DES , the first round is?
Correct Answer
A. Key transformation
Explanation
The first round in the 16 rounds of DES is the Key transformation. This step involves the initial transformation of the key before it is used in the encryption process. It ensures that the key is in the correct format and ready to be used for further operations. This step is crucial in ensuring the security and effectiveness of the DES encryption algorithm.
8.
IDEA stands for?
Correct Answer
B. International Data Encryption Algorithm
Explanation
IDEA stands for International Data Encryption Algorithm. This algorithm is a symmetric key block cipher that is widely used for encryption and decryption of data. It was developed in the early 1990s and is known for its strong security and efficiency. IDEA uses a 128-bit key and operates on 64-bit blocks of data. It has been adopted by various organizations and is considered one of the most secure encryption algorithms available.
9.
IDEA has ___ rounds.
Correct Answer
A. 8
Explanation
IDEA has 8 rounds. This means that in the IDEA encryption algorithm, the process of encrypting or decrypting a block of data requires 8 iterations or rounds of operations. Each round involves a combination of substitution, permutation, and modular arithmetic operations to provide a high level of security. The number of rounds is chosen to balance security and efficiency, as increasing the number of rounds increases security but also increases the computational overhead. Therefore, in the case of IDEA, 8 rounds have been determined to be sufficient for providing strong encryption.
10.
RC4 was invented in the year______
Correct Answer
C. 1987
Explanation
The correct answer is 1987. This is the year in which RC4 was invented.
11.
Blowfish has was developed by?
Correct Answer
B. Bruce Schneier
Explanation
Bruce Schneier is the correct answer because he is one of the developers of the Blowfish algorithm. Blowfish is a symmetric-key block cipher that was designed in 1993 by Bruce Schneier as an alternative to existing encryption algorithms. It is known for its simplicity and speed, and it has been widely used in various applications and protocols. Therefore, Bruce Schneier's name is associated with the development of Blowfish.
12.
In RSA, the first step is to accept two large prime numbers.
Correct Answer
B. P and Q
Explanation
In RSA, the first step is to accept two large prime numbers, denoted as P and Q. These prime numbers are crucial for generating the public and private keys used in the RSA encryption algorithm. The product of these two prime numbers, N = P * Q, is used as the modulus for encryption and decryption operations. Therefore, the correct answer is P and Q.
13.
What defines the details of the cryptographic algorithm?
Correct Answer
A. Algorithm types
Explanation
The details of a cryptographic algorithm are defined by the algorithm types. Different algorithm types have distinct characteristics and properties that determine how the encryption or decryption process is carried out. The specific algorithm type chosen for a cryptographic system will determine factors such as the key length, encryption strength, and overall security level. Therefore, understanding the algorithm types is essential in order to implement and utilize cryptographic algorithms effectively.
14.
____________ defines the encryption of one plain text at a time.
Correct Answer
C. Stream cipher
Explanation
A stream cipher is a type of encryption that operates on individual bits or characters of plain text at a time. It generates a stream of random or pseudorandom bits, which are combined with the plain text using a bitwise operation to produce the cipher text. This process is repeated for each character or bit of the plain text, allowing for efficient encryption of data. Unlike block ciphers, which operate on fixed-sized blocks of plain text, stream ciphers can encrypt data of any length. Therefore, a stream cipher is the correct answer as it defines the encryption of one plain text at a time.
15.
What defines the encryption of one block of bit at a time?
Correct Answer
D. Block cipher
Explanation
A block cipher is a type of encryption that operates on fixed-size blocks of data, typically 64 or 128 bits at a time. It divides the plaintext into blocks and encrypts each block separately using a specific algorithm and a secret key. This ensures that each block is transformed into a corresponding block of ciphertext, making it difficult for an attacker to decrypt the message without the correct key. Block ciphers are commonly used in various encryption protocols and algorithms to provide secure communication and data protection.
16.
HMAC is a type of?
Correct Answer
A. Message digest
Explanation
HMAC (Hash-based Message Authentication Code) is a type of message digest. It is a cryptographic algorithm that combines a secret key with a hash function to produce a fixed-size output called a message digest. This message digest can be used to verify the integrity and authenticity of a message, ensuring that it has not been tampered with during transmission. HMAC provides a way to authenticate both the message and the sender, making it a type of message digest.
17.
MAC stands for?
Correct Answer
A. Message Authentication Code
Explanation
MAC stands for Message Authentication Code. A Message Authentication Code is a cryptographic code that is used to verify the integrity and authenticity of a message or data. It is generated using a secret key and applied to the message, allowing the receiver to verify that the message has not been tampered with during transmission and that it originated from the expected sender. MAC provides a way to ensure the integrity and authenticity of the message, making it an essential component of secure communication systems.
18.
Which is the most simplest mode in algorithm mode?
Correct Answer
B. Electronic code book
Explanation
The Electronic Code Book (ECB) mode is the simplest mode in algorithm mode. In ECB mode, each plaintext block is encrypted independently using the same key, resulting in the same ciphertext for the same plaintext block. This lack of dependency between blocks makes ECB mode vulnerable to certain attacks, such as pattern recognition and ciphertext manipulation. However, despite its simplicity, ECB mode is still widely used in certain applications where confidentiality is not a major concern.
19.
Initial permutation divides the plain text into two halves of?
Correct Answer
A. 32 bits
Explanation
The initial permutation divides the plain text into two halves of 32 bits. This means that the plain text is split into two equal parts, each containing 32 bits of data. This division is an important step in the encryption process, as it allows for further manipulation and transformation of the data in subsequent rounds of the encryption algorithm.
20.
The last step of des is
Correct Answer
C. Final permutation
Explanation
The last step of DES (Data Encryption Standard) is the Final Permutation. After the S-box substitution, the Final Permutation is applied to the data to provide the final output. This permutation rearranges the bits of the data according to a specific permutation table. It is an important step in the DES algorithm as it provides additional confusion and diffusion to the encrypted data, making it more secure.
21.
Which of the following is the objective Of blowfish?
Correct Answer
D. All of thes
Explanation
Blowfish is a symmetric-key block cipher algorithm designed to be fast, compact, and simple. It is known for its efficiency in both software and hardware implementations. The algorithm is designed to be simple enough to be easily implemented on various platforms and efficient enough to provide fast encryption and decryption. Additionally, Blowfish is also designed to be compact, meaning it requires less memory and storage space. Therefore, the objective of Blowfish is to be fast, compact, and simple, making "All of these" the correct answer.
22.
RSA is a________
Correct Answer
B. Asymmetric
Explanation
RSA is an asymmetric encryption algorithm. It uses a pair of keys, a public key and a private key, to encrypt and decrypt data. The public key is used for encryption, while the private key is used for decryption. This makes RSA asymmetric because the keys used for encryption and decryption are different. In contrast, symmetric encryption algorithms use the same key for both encryption and decryption. Therefore, the correct answer is "Asymmetric".
23.
In rsa algorithm n is calculated as?
Correct Answer
C. P*Q
Explanation
In the RSA algorithm, the value of n is calculated by multiplying the two prime numbers P and Q. This is because the security of the RSA encryption relies on the factoring problem, which states that it is computationally difficult to determine the prime factors of a large composite number. Therefore, by multiplying P and Q to obtain n, it becomes challenging for an attacker to factorize n and retrieve the original prime numbers.
24.
Select a public key E such that it should not be a factor of (P-1) and (Q-1)
Correct Answer
A. True
Explanation
The statement is true because in order for a public key E to be secure, it should not be a factor of (P-1) and (Q-1). If E is a factor of (P-1) or (Q-1), it would make it easier for an attacker to calculate the private key and break the encryption. Therefore, it is important to choose a public key E that is not a factor of (P-1) and (Q-1) to ensure the security of the encryption.
25.
The blowfish algorithm executes the ____________ algorithm for subkey generation.
Correct Answer
C. Rijndael
Explanation
The blowfish algorithm executes the Rijndael algorithm for subkey generation. Rijndael is a symmetric key block cipher algorithm that is used in the Advanced Encryption Standard (AES). The blowfish algorithm, on the other hand, is a symmetric key block cipher that operates on 64-bit blocks and can have a variable key length up to 448 bits. By using the Rijndael algorithm for subkey generation, the blowfish algorithm ensures the generation of secure and strong subkeys for encryption and decryption processes.
26.
Knapsack algorithm was developed by?
Correct Answer
C. Both
Explanation
The correct answer is "Both." The Knapsack algorithm was developed by both Ralph Merkle and Martin Hellman.
27.
In MD-5 the input is divided into how many bit block?
Correct Answer
B. 512
Explanation
In MD5, the input is divided into 512-bit blocks. MD5 is a cryptographic hash function that takes an input message and produces a 128-bit hash value. To process the input, it breaks it down into chunks or blocks of 512 bits each. Each block is then processed by the algorithm to generate the hash value.
28.
How many chaining variables are used in MD-5?
Correct Answer
B. 4
Explanation
MD-5 (Message Digest Algorithm 5) uses four chaining variables. Chaining variables are intermediate values used in the computation of the hash function. In MD-5, the algorithm processes the input message in blocks of 512 bits and updates the chaining variables after each block. The four chaining variables are A, B, C, and D, which are initialized to fixed constants at the beginning of the computation and updated based on the message blocks. These variables play a crucial role in the compression function of MD-5, ensuring the integrity and security of the hash output.
29.
SHA stands for?
Correct Answer
A. Secure hash algorithm
Explanation
SHA stands for Secure Hash Algorithm. It is a cryptographic hash function that is commonly used in various security applications and protocols. The purpose of SHA is to generate a unique fixed-size hash value from input data of any size. This hash value is used to verify the integrity and authenticity of the data, as even a small change in the input data will result in a completely different hash value. Therefore, SHA provides a secure and reliable way to ensure data integrity and protect against tampering or unauthorized modifications.
30.
In SHA-512 the input is divided into how many bit block?
Correct Answer
B. 1024
Explanation
In SHA-512, the input is divided into 1024-bit blocks. This means that the input message is split into chunks of 1024 bits before being processed by the SHA-512 algorithm. Each block is then processed independently, using a series of mathematical operations, to produce the final hash value. This division into 1024-bit blocks allows for efficient processing of large input messages while ensuring the security and integrity of the hash function.
31.
The knapsack is an algorithm for?
Correct Answer
A. Public key encryption
Explanation
The knapsack algorithm is not specifically designed for public key encryption, private key encryption, or public-private key encryption. Therefore, the correct answer is "none".
32.
Blowfish has?
Correct Answer
C. Both
Explanation
Blowfish is a symmetric-key block cipher that uses a Feistel network structure. It is capable of both subkey generation and data encryption. Subkey generation involves generating a series of round keys from the original key, which are used in the encryption process. Blowfish then uses these subkeys to encrypt the data in blocks. Therefore, the correct answer is "Both" as Blowfish performs both subkey generation and data encryption.