This set of Cyber Security Problems focuses on “Types of Cryptography – 2”.

1. _____________________ is the art & science of cracking the cipher-text without knowing the key.

a) Cracking

b) Cryptanalysis

c) Cryptography

d) Crypto-hacking

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Explanation: Cryptanalysis is the art & science of cracking the cipher-text without knowing the key. This technique is also implemented for designing new cryptographic algorithms or to test their strengths.

2. The process of disguising plaintext in such a way that its substance gets hidden (into what is known as cipher-text) is called _________________

a) cryptanalysis

b) decryption

c) reverse engineering

d) encryption

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Explanation: Cryptography is a means of storing & transmitting information in a specific format so that only those for whom it is planned can understand or process it. The process of disguising plaintext in such a way that its substance gets hidden (into what is known as cipher-text) is called encryption.

3. The method of reverting the encrypted text which is known as cipher text to its original form i.e. plain text is known as ________________

a) cryptanalysis

b) decryption

c) reverse engineering

d) encryption

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Explanation: Cryptography helps in securing a specific format so that only intended users can understand or process it. The method of reversing the encrypted text which is known as cipher text to its original form i.e. plain text is known as decryption.

4. Which of the following is not the primary objective of cryptography?

a) Confidentiality

b) Data Integrity

c) Data Redundancy

d) Authentication

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Explanation: The key intent of implementing cryptography is to offer the following 4 fundamental information security features. These are Confidentiality, Data Integrity, Authentication and non-repudiation.

5. Which of the following is not the primary objective of cryptography?

a) Confidentiality

b) Data Redundancy

c) Non-repudiation

d) Authentication

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Explanation: Cryptography offers 4 fundamental information security features. These are Confidentiality, Data Integrity, Authentication and non-repudiation.

6. Cryptography offers a set of required security services. Which of the following is not among that 4 required security services?

a) Encryption

b) Message Authentication codes

c) Hash functions

d) Steganography

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Explanation: There are 4 desired & necessary security services are encryption, Message Authentication Codes (MAC), digital signatures and hash functions. These help in securing the transmission of data.

7. A cryptosystem is also termed as ______________

a) secure system

b) cipher system

c) cipher-text

d) secure algorithm

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Explanation: Cryptography is a means of storing & transmitting information in a specific format so that only those for whom it is planned can understand or process it. Cryptosystem which is also known as a cipher system is execution of cryptographic algorithms & techniques.

8. ______________ is the mathematical procedure or algorithm which produces a cipher-text for any specified plaintext.

a) Encryption Algorithm

b) Decryption Algorithm

c) Hashing Algorithm

d) Tuning Algorithm

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Explanation: Encryption Algorithm is the mathematical procedure or algorithm which produces a cipher-text for any specified plaintext. Inputs it takes are the plain text and the key.

9. _______________ takes the plain text and the key as input for creating cipher-text.

a) Decryption Algorithm

b) Hashing Algorithm

c) Tuning Algorithm

d) Encryption Algorithm

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Explanation: Encryption Algorithm is the mathematical procedure or algorithm which produces a cipher-text for any specified plaintext. Inputs it takes are the plain text and the key.

10. ____________________ is a mathematical algorithm that produces a unique plain text for a given cipher text along with a decryption key.

a) Decryption Algorithm

b) Hashing Algorithm

c) Tuning Algorithm

d) Encryption Algorithm

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Explanation: Decryption Algorithm is a mathematical algorithm that produces a unique plain text for a given cipher text along with a decryption key. Inputs it takes are the cipher-text & the decryption key.

11. A set of all probable decryption keys are collectively termed as ____________

a) key-stack

b) key bunch

c) key space

d) key pack

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Explanation: A set of all probable decryption keys are collectively termed as key space. A mathematical algorithm which produces a unique plain text for a given cipher text along with a decryption key is called a decryption algorithm.

12. Encryption-decryption in cryptosystem is done in ______ ways.

a) 4

b) 3

c) 5

d) 2

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Explanation: Cryptosystem which is also known as cipher system is the execution of cryptographic algorithms & techniques. Encryption-decryption in a cryptosystem is done in two ways. These are by Symmetric Key Encryption and by Asymmetric Key Encryption.

13. In _____________________ same keys are implemented for encrypting as well as decrypting the information.

a) Symmetric Key Encryption

b) Asymmetric Key Encryption

c) Asymmetric Key Decryption

d) Hash-based Key Encryption

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Explanation: Encryption-decryption in a cryptosystem is done in two ways. These are by Symmetric Key Encryption and by Asymmetric Key Encryption. In Symmetric Key Encryption, same keys are implemented for encrypting as well as decrypting the information.

14. In __________________ 2 different keys are implemented for encrypting as well as decrypting that particular information.

a) Symmetric Key Encryption

b) Asymmetric Key Encryption

c) Asymmetric Key Decryption

d) Hash-based Key Encryption

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Explanation: In Asymmetric Key Encryption 2 different keys are implemented for encrypting as well as decrypting that particular information. Inputs it takes are the plain text and 2 different key.

15. A set of all probable decryption keys are collectively termed as key space.

a) True

b) False

View Answer

Explanation: Decryption Algorithm is a mathematical algorithm that produces a unique plain text for a given cipher text along with a decryption key. A set of all probable decryption keys are collectively termed as key space.

**Sanfoundry Global Education & Learning Series – Cyber Security.**

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