Cryptography and Network Security Principles
Questions and Answers
1. Is the most common method used to conceal small blocks of data, such as encryption
keys and hash function values, which are used in digital signatures -ANSW
Asymmetric encryption
2. A common technique for masking contents of messages or other information traffic so
that opponents cannot extract the information from the message is. -ANSW encryption
3. Involves the passive capture of a data unit and its subsequent retransmission to
produce an unauthorized effect. -ANSW Replay
4. Refers to the use of multiple, overlapping protection approaches addressing the
people, technology, and operational aspects of information systems. -ANSW Layering
5. A loss of __________ is the unauthorized disclosure of information -ANSW
Confidentiality
6. Verifying that users are who they say they are and that each input arriving at the
system came from a trusted source is -ANSW Authenticity
7. A _________ level breach of security could cause a significant degradation in
mission capability to an extent and duration that the organization is able to perform its
primary functions, but the effectiveness of the functions is significantly reduced. -ANSW
Moderate
8. A __________ is any action that compromises the security of information owned by
an organization -ANSW Security Attack
9. A __________ takes place when one entity pretends to be a different entity. -ANSW
masquerade
A(n) __________ service is one that protects a system to ensure its availability and
addresses the security concerns raised by denial- of- service attacks. -ANSW
Availability
1. Techniques map plaintext elements (characters, bits) into ciphertext elements. -
ANSW Substitution
2. Joseph Mauborgne proposed an improvement to the Vernam cipher that uses a
random key that is as long as the message so that the key does not need to be
repeated. The key is used to encrypt and decrypt a single message and then is
, discarded. Each new message requires a new key of the same length as the new
message. This scheme is known as a(n) -ANSW One Time Pad
3. An original intelligible message fed into the algorithm as input is known as
_________ , while the coded message produced as output is called the -ANSW
plaintext, ciphertext
4. Restoring the plaintext from the ciphertext is -ANSW Deciphering
5. A __________ attack involves trying every possible key until an intelligible translation
of the ciphertext is obtained -ANSW Brute force
6. Techniques used for deciphering a message without any knowledge of the
enciphering details is. -ANSW Cryptanalyses
7. The ___________ takes the ciphertext and the secret key and produces the original
plaintext. It is essentially the encryption algorithm run in reverse -ANSW Decryption
Algorithm
8. If both sender and receiver use the same key, the system is referred to as -ANSW
conventional encryption
9. attacks exploit the characteristics of the algorithm to attempt to deduce a specific
plaintext or to deduce the key being used -ANSW Cryptanalytic
10. The __________ was used as the standard field system by the British Army in
World War I and was used by the U.S. Army and other Allied forces during World War II.
-ANSW Playfair Cipher
1. DES exhibits the classic __block cipher structure, which consists of a number of
identical rounds of processing. -ANSW Feistel
2. A sequence of plaintext elements is replaced by a __________ of that sequence
which means that no elements are added, deleted or replaced in the sequence, but
rather the order in which the elements appear in the sequence is changed -ANSW
permutation
3. A ____cipher is one that encrypts a digital data stream one bit or one byte at a time?
-ANSW Stream
4. The vast majority of network-based symmetric cryptographic applications make use
of ____ ciphers. -ANSW Block
5. A _______cipher is one in which a block of plaintext is treated as a whole and used
to produce a ciphertext block of equal length -ANSW Block
Questions and Answers
1. Is the most common method used to conceal small blocks of data, such as encryption
keys and hash function values, which are used in digital signatures -ANSW
Asymmetric encryption
2. A common technique for masking contents of messages or other information traffic so
that opponents cannot extract the information from the message is. -ANSW encryption
3. Involves the passive capture of a data unit and its subsequent retransmission to
produce an unauthorized effect. -ANSW Replay
4. Refers to the use of multiple, overlapping protection approaches addressing the
people, technology, and operational aspects of information systems. -ANSW Layering
5. A loss of __________ is the unauthorized disclosure of information -ANSW
Confidentiality
6. Verifying that users are who they say they are and that each input arriving at the
system came from a trusted source is -ANSW Authenticity
7. A _________ level breach of security could cause a significant degradation in
mission capability to an extent and duration that the organization is able to perform its
primary functions, but the effectiveness of the functions is significantly reduced. -ANSW
Moderate
8. A __________ is any action that compromises the security of information owned by
an organization -ANSW Security Attack
9. A __________ takes place when one entity pretends to be a different entity. -ANSW
masquerade
A(n) __________ service is one that protects a system to ensure its availability and
addresses the security concerns raised by denial- of- service attacks. -ANSW
Availability
1. Techniques map plaintext elements (characters, bits) into ciphertext elements. -
ANSW Substitution
2. Joseph Mauborgne proposed an improvement to the Vernam cipher that uses a
random key that is as long as the message so that the key does not need to be
repeated. The key is used to encrypt and decrypt a single message and then is
, discarded. Each new message requires a new key of the same length as the new
message. This scheme is known as a(n) -ANSW One Time Pad
3. An original intelligible message fed into the algorithm as input is known as
_________ , while the coded message produced as output is called the -ANSW
plaintext, ciphertext
4. Restoring the plaintext from the ciphertext is -ANSW Deciphering
5. A __________ attack involves trying every possible key until an intelligible translation
of the ciphertext is obtained -ANSW Brute force
6. Techniques used for deciphering a message without any knowledge of the
enciphering details is. -ANSW Cryptanalyses
7. The ___________ takes the ciphertext and the secret key and produces the original
plaintext. It is essentially the encryption algorithm run in reverse -ANSW Decryption
Algorithm
8. If both sender and receiver use the same key, the system is referred to as -ANSW
conventional encryption
9. attacks exploit the characteristics of the algorithm to attempt to deduce a specific
plaintext or to deduce the key being used -ANSW Cryptanalytic
10. The __________ was used as the standard field system by the British Army in
World War I and was used by the U.S. Army and other Allied forces during World War II.
-ANSW Playfair Cipher
1. DES exhibits the classic __block cipher structure, which consists of a number of
identical rounds of processing. -ANSW Feistel
2. A sequence of plaintext elements is replaced by a __________ of that sequence
which means that no elements are added, deleted or replaced in the sequence, but
rather the order in which the elements appear in the sequence is changed -ANSW
permutation
3. A ____cipher is one that encrypts a digital data stream one bit or one byte at a time?
-ANSW Stream
4. The vast majority of network-based symmetric cryptographic applications make use
of ____ ciphers. -ANSW Block
5. A _______cipher is one in which a block of plaintext is treated as a whole and used
to produce a ciphertext block of equal length -ANSW Block
