Test
Quiz 7
Preguntas del test (25)
1The process of transforming ciphertext to plaintext is known as:
- ADecryption
- BEncryption
- CKey recovery
- DHashing
2Which of the following statements is true about the Vernam cipher:
- AIt is a polyalphabetic cipher
- BIt is a running-key cipher
- CThe encryption key is used for only one message
- DAnother name for it is a one-time hash
3What is the minimum key length for a one-time pad?
- A128 bits
- B64 bits
- C56 bits
- DThe length of the plaintext message
4All of the following statements about the polyalphabetic cipher are true EXCEPT:
- AIt is a form of one-time pad
- BIt is resistant to frequency analysis attacks
- CIt uses multiple substitution alphabets
- DIt is a type of substitution cipher
5A running-key cipher can be used when:
- AThe plaintext is longer than the encryption key
- BThe plaintext is shorter than the encryption key
- CThe plaintext is streaming media
- DThe plaintext is changing rapidly
6In modulo arithmetic, when A – B
- A26 is subtracted from the result
- B100 is added to the result
- C26 is added to the result
- D32 is added to the result
7A 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:
- ABlock cipher
- BStream cipher
- CRunning key cipher
- DVernam Cipher
8In an electronic codebook (ECB) cipher, each block of ciphertext:
- AIs used to encrypt the next block
- BIs used to encrypt the previous block
- CIs used to decrypt the next block
- DIs not used to encrypt the next block
9The encryption mode where ciphertext output from each encrypted plaintext block in the encryption used for the next block is known as:
- ACipher feedback
- BOutput feedback
- CCipher block chaining
- DElectronic codebook
10Public key cryptography is another name for:
- ASecure Sockets Layer
- BAsymmetric cryptography
- CSymmetric key cryptography
- DKerberos
11Public key cryptography is so-named because:
- AIt is the world standard for HTTPS
- BIt works on all popular computer operating systems
- CIt uses an encryption key that can be released to the public
- DThe encryption algorithms reside in the public domain
12A 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:
- AFISH
- BTwofish
- CBlowfish
- DCAST
13A particular encryption algorithm transforms plaintext to ciphertext by XORing the plaintext with the encryption key. This is known as:
- AElectronic codebook
- BCipher block chaining
- CBlock cipher
- DStream cipher
14Two parties that have never communicated before wish to send messages using symmetric encryption key cryptography. How should the parties begin?
- AThe receiving party should send its public encryption key to the transmitting party
- BEach party should exchange public encryption keys
- CEach party should send the encryption key via the communications channel to the other party
- DOne party should transmit the encryption key via an out of band communications channel to the other party
15Two parties that have never communicated before wish to send messages using asymmetric key cryptography. How should the parties begin?
- AThe receiving party should send its private encryption key to the transmitting party.
- BThe transmitting party should send its private encryption key to the receiving party.
- CThe receiving party should send its public encryption key to the transmitting party.
- DThe transmitting party should send its public encryption key to the receiving party.
16Two 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?
- ARequest a new public key from Party A
- BRequest a new private key from Party A
- CSend a new public key to Party A
- DSend a new private key to Party A
17The Advanced Encryption Standard is another name for which cipher:
- ADigital Encryption Algorithm (DEA)
- B3DES
- CRijndael
- DInternational Data Encryption Algorithm (IDEA)
18The Data Encryption Standard:
- AIs used by Secure Sockets Layer (SSL) encryption
- BHas been replaced by the International Data Encryption Algorithm (IDEA)
- CUses a 64-bit encryption key
- DUses a 56-bit encryption key
19Two parties are exchanging messages using public key cryptography. Which of the following statements describes the proper procedure for transmitting an encrypted message?
- AThe sender encrypts the message using the recipient’s public key, and the recipient decrypts the message using the recipient’s private key
- BThe sender encrypts the message using the sender’s public key, and the recipient decrypts the message using the recipient’s public key
- CThe sender encrypts the message using the sender’s private key, and the recipient decrypts the message using the recipient’s private key
- DThe sender encrypts the message using the sender’s public key, and the recipient decrypts the message using the sender’s public key
20A stream cipher encrypts data by XORing plaintext with the encryption key. How is the ciphertext converted back into plaintext?
- AXORing it with the encryption key
- BXORing it with the inverse of the encryption key
- CANDing it with the encryption key
- DNANDing it with the encryption key
21The purpose of digitally signing a message is to ensure:
- AIntegrity of the sender
- BConfidentiality of the message
- CAuthenticity of the sender
- DConfidentiality of the sender
22The purpose of digitally signing a message is to ensure:
- AIntegrity of the message
- BConfidentiality of the message
- CIntegrity of the sender
- DConfidentiality of the sender
23The purpose of the Diffie-Hellman key exchange protocol is:
- ATo decrypt a symmetric encryption key
- BTo encrypt a symmetric encryption key
- CTo permit two parties who have never communicated to establish public encryption keys
- DTo permit two parties who have never communicated to establish a secret encryption key
24An 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:
- ACiphertext only attack
- BChosen ciphertext attack
- CChosen plaintext attack
- DMan in the middle attack
25Which is the best approach for two parties who wish to establish a means for confirming the confidentiality and integrity of messages that they exchange:
- ADigital signatures
- BEncryption and digital signatures
- CKey exchange
- DEncryption
Información
- Descripción
- 1 CSI270 Test sobre Quiz 7, creado por Joshua Villy el 08/05/2013.
- Autor
- Joshua Villy
- Idioma
- English
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