Joshua Villy
Quiz por , criado more than 1 year ago

1 CSI270 Quiz sobre Quiz 7, criado por Joshua Villy em 08-05-2013.

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Joshua Villy
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Quiz 7

Questão 1 de 25

1

The process of transforming ciphertext to plaintext is known as:

Selecione uma das seguintes:

  • Decryption

  • Encryption

  • Key recovery

  • Hashing

Explicação

Questão 2 de 25

1

Which of the following statements is true about the Vernam cipher:

Selecione uma das seguintes:

  • It is a polyalphabetic cipher

  • It is a running-key cipher

  • The encryption key is used for only one message

  • Another name for it is a one-time hash

Explicação

Questão 3 de 25

1

What is the minimum key length for a one-time pad?

Selecione uma das seguintes:

  • 128 bits

  • 64 bits

  • 56 bits

  • The length of the plaintext message

Explicação

Questão 4 de 25

1

All of the following statements about the polyalphabetic cipher are true EXCEPT:

Selecione uma das seguintes:

  • It is a form of one-time pad

  • It is resistant to frequency analysis attacks

  • It uses multiple substitution alphabets

  • It is a type of substitution cipher

Explicação

Questão 5 de 25

1

A running-key cipher can be used when:

Selecione uma das seguintes:

  • The plaintext is longer than the encryption key

  • The plaintext is shorter than the encryption key

  • The plaintext is streaming media

  • The plaintext is changing rapidly

Explicação

Questão 6 de 25

1

In modulo arithmetic, when A – B

Selecione uma das seguintes:

  • 26 is subtracted from the result

  • 100 is added to the result

  • 26 is added to the result

  • 32 is added to the result

Explicação

Questão 7 de 25

1

A computer user is listening to an audio broadcast on the Internet through an SSL VPN. The type of encryption cipher used in this case is:

Selecione uma das seguintes:

  • Block cipher

  • Stream cipher

  • Running key cipher

  • Vernam Cipher

Explicação

Questão 8 de 25

1

In an electronic codebook (ECB) cipher, each block of ciphertext:

Selecione uma das seguintes:

  • Is used to encrypt the next block

  • Is used to encrypt the previous block

  • Is used to decrypt the next block

  • Is not used to encrypt the next block

Explicação

Questão 9 de 25

1

The encryption mode where ciphertext output from each encrypted plaintext block in the encryption used for the next block is known as:

Selecione uma das seguintes:

  • Cipher feedback

  • Output feedback

  • Cipher block chaining

  • Electronic codebook

Explicação

Questão 10 de 25

1

Public key cryptography is another name for:

Selecione uma das seguintes:

  • Secure Sockets Layer

  • Asymmetric cryptography

  • Symmetric key cryptography

  • Kerberos

Explicação

Questão 11 de 25

1

Public key cryptography is so-named because:

Selecione uma das seguintes:

  • It is the world standard for HTTPS

  • It works on all popular computer operating systems

  • It uses an encryption key that can be released to the public

  • The encryption algorithms reside in the public domain

Explicação

Questão 12 de 25

1

A security manager is searching for an encryption algorithm to be used to encrypt data files containing sensitive information. Which of the following algorithms should NOT be considered:

Selecione uma das seguintes:

  • FISH

  • Twofish

  • Blowfish

  • CAST

Explicação

Questão 13 de 25

1

A particular encryption algorithm transforms plaintext to ciphertext by XORing the plaintext with the encryption key. This is known as:

Selecione uma das seguintes:

  • Electronic codebook

  • Cipher block chaining

  • Block cipher

  • Stream cipher

Explicação

Questão 14 de 25

1

Two parties that have never communicated before wish to send messages using symmetric encryption key cryptography. How should the parties begin?

Selecione uma das seguintes:

  • The receiving party should send its public encryption key to the transmitting party

  • Each party should exchange public encryption keys

  • Each party should send the encryption key via the communications channel to the other party

  • One party should transmit the encryption key via an out of band communications channel to the other party

Explicação

Questão 15 de 25

1

Two parties that have never communicated before wish to send messages using asymmetric key cryptography. How should the parties begin?

Selecione uma das seguintes:

  • The receiving party should send its private encryption key to the transmitting party.

  • The transmitting party should send its private encryption key to the receiving party.

  • The receiving party should send its public encryption key to the transmitting party.

  • The transmitting party should send its public encryption key to the receiving party.

Explicação

Questão 16 de 25

1

Two parties, Party A and Party B, regularly exchange messages using public key cryptography. One party, Party A, believes that its private encryption key has been compromised. What action should Party B take?

Selecione uma das seguintes:

  • Request a new public key from Party A

  • Request a new private key from Party A

  • Send a new public key to Party A

  • Send a new private key to Party A

Explicação

Questão 17 de 25

1

The Advanced Encryption Standard is another name for which cipher:

Selecione uma das seguintes:

  • Digital Encryption Algorithm (DEA)

  • 3DES

  • Rijndael

  • International Data Encryption Algorithm (IDEA)

Explicação

Questão 18 de 25

1

The Data Encryption Standard:

Selecione uma das seguintes:

  • Is used by Secure Sockets Layer (SSL) encryption

  • Has been replaced by the International Data Encryption Algorithm (IDEA)

  • Uses a 64-bit encryption key

  • Uses a 56-bit encryption key

Explicação

Questão 19 de 25

1

Two parties are exchanging messages using public key cryptography. Which of the following statements describes the proper procedure for transmitting an encrypted message?

Selecione uma das seguintes:

  • The sender encrypts the message using the recipient’s public key, and the recipient decrypts the message using the recipient’s private key

  • The sender encrypts the message using the sender’s public key, and the recipient decrypts the message using the recipient’s public key

  • The sender encrypts the message using the sender’s private key, and the recipient decrypts the message using the recipient’s private key

  • The sender encrypts the message using the sender’s public key, and the recipient decrypts the message using the sender’s public key

Explicação

Questão 20 de 25

1

A stream cipher encrypts data by XORing plaintext with the encryption key. How is the ciphertext converted back into plaintext?

Selecione uma das seguintes:

  • XORing it with the encryption key

  • XORing it with the inverse of the encryption key

  • ANDing it with the encryption key

  • NANDing it with the encryption key

Explicação

Questão 21 de 25

1

The purpose of digitally signing a message is to ensure:

Selecione uma das seguintes:

  • Integrity of the sender

  • Confidentiality of the message

  • Authenticity of the sender

  • Confidentiality of the sender

Explicação

Questão 22 de 25

1

The purpose of digitally signing a message is to ensure:

Selecione uma das seguintes:

  • Integrity of the message

  • Confidentiality of the message

  • Integrity of the sender

  • Confidentiality of the sender

Explicação

Questão 23 de 25

1

The purpose of the Diffie-Hellman key exchange protocol is:

Selecione uma das seguintes:

  • To decrypt a symmetric encryption key

  • To encrypt a symmetric encryption key

  • To permit two parties who have never communicated to establish public encryption keys

  • To permit two parties who have never communicated to establish a secret encryption key

Explicação

Questão 24 de 25

1

An attacker is attempting to learn the encryption key that is used to protect messages being sent between two parties. The attacker is able to create his own messages, get them encrypted by one of the parties, and can then examine the ciphertext for his message. This type of attack is known as:

Selecione uma das seguintes:

  • Ciphertext only attack

  • Chosen ciphertext attack

  • Chosen plaintext attack

  • Man in the middle attack

Explicação

Questão 25 de 25

1

Which is the best approach for two parties who wish to establish a means for confirming the confidentiality and integrity of messages that they exchange:

Selecione uma das seguintes:

  • Digital signatures

  • Encryption and digital signatures

  • Key exchange

  • Encryption

Explicação