CPTR 352 FINAL REVIEW QUESTIONS
Denial of Service - Answer -Erasing a portion of the disk without authorization is likely
to lead to ______.
information destruction - Answer -Deleting another user's file without authorization is
considered _____.
User deception - Answer -Modifying the "from" field in an email message and asking for
the recipient's social security number is considered _____.
Destruction of information - Answer -Installing a program to randomly kill processes is
likely to lead to _____>
Logic bomb - Answer -unauthorized code inserted into the system and executed at a
specific time to perform some destructive action
Back Door - Answer -A mechanism that bypasses user authentication
Information leaking - Answer -The disclosure of confidential or secret information by a
legitimate user to an unauthorized user
Login Spoofing - Answer -An approach where a legitimate user presents a fake login
screen to an unsuspecting user
Phishing - Answer -A PC owned and used by a single user can be attacked using
_____.
education users about the dangers of phishing - Answer -A computer in a public lab or
library can be protected from phishing by ____.
providing a service that prepares an individual's tax return and then emails all people on
the user's contacts list to advertise itself. - Answer -The following action is an example
of a Trojan Horse attack.
5 - Answer -A challenge-response system uses a single byte (8 bits) to represent each
of r, pw, and H(r, pw). The function H multiplies r and pw to produce a 16-bit value, then
returns the middle 8 bits as the result. A user's password is 12 (or 0000 1100 in binary).
5If the system generates r = 7, then the value of H(r, pw) returned to the system by the
user is _____.
10,000 - Answer -A hacker obtains a copy of a password file that contains 10 entries of
user ID, a unique salt, and a hash of the salted password. If the hacker knows the
hashing function (it is part of the open source OS), how many hash values does the
, hacker need to calculate to check each word in a dictionary of 1,000 common
passwords.
no imposter attempts are accepted - Answer -In a biometric user authentication system,
imposter attempts generate values between 0 and 0.5, while genuine attempts generate
values between 0.3 and 1. If the threshold is placed at 0.5 then _____.
Dn - Answer -A process p in domain _____ can read all listed objects.
D3 - Answer -Object O1 can be executed by a process in domain _____.
False - Answer -A process in D2 can remove x from A[Dn, O2].
False - Answer -A process in D3 can add x to A[Di, Oj]
2 - Answer -The shortest capability list has the length _____.
3 - Answer -The longest access list has the length _____.
Secrecy
Authenticity
Non-repudiation - Answer -What are the three main goals of cryptography?
1 - Answer -How many keys are used by secret-key cryptography?
DOG - Answer -The encryption function replaces all letters in odd positions of the
plaintext by letters shifted k positions to the right according to the English alphabet.
Letters in even positions are left unchanged. Ex: With k = 2, the letter A in any odd
position is replaced by C, the letter B is replaced by D, etc. The decryption function
reverses the substitutions. Thus k becomes the key for both encryption and decryption.
With k = 3, the plaintext corresponding to the ciphertext GOJ is _____.
2 or more - Answer -How many keys are used with public-key cryptography?
authenticity - Answer -A message authentication code (MAC) is an encrypted hash of a
larger sequence of bytes. A MAC guarantees ___ of a message.
impossible - Answer -Using secret-key cryptography instead of public-key would make
digital signatures _____.
bytes, records - Answer -Depending on the file system (FS), a file can be viewed as an
unstructured stream of ______ or a series of ________.
byte-oriented files - Answer -Read/write n bytes is applicable to
fixed-length record files - Answer -Read/write record k is applicable to
Denial of Service - Answer -Erasing a portion of the disk without authorization is likely
to lead to ______.
information destruction - Answer -Deleting another user's file without authorization is
considered _____.
User deception - Answer -Modifying the "from" field in an email message and asking for
the recipient's social security number is considered _____.
Destruction of information - Answer -Installing a program to randomly kill processes is
likely to lead to _____>
Logic bomb - Answer -unauthorized code inserted into the system and executed at a
specific time to perform some destructive action
Back Door - Answer -A mechanism that bypasses user authentication
Information leaking - Answer -The disclosure of confidential or secret information by a
legitimate user to an unauthorized user
Login Spoofing - Answer -An approach where a legitimate user presents a fake login
screen to an unsuspecting user
Phishing - Answer -A PC owned and used by a single user can be attacked using
_____.
education users about the dangers of phishing - Answer -A computer in a public lab or
library can be protected from phishing by ____.
providing a service that prepares an individual's tax return and then emails all people on
the user's contacts list to advertise itself. - Answer -The following action is an example
of a Trojan Horse attack.
5 - Answer -A challenge-response system uses a single byte (8 bits) to represent each
of r, pw, and H(r, pw). The function H multiplies r and pw to produce a 16-bit value, then
returns the middle 8 bits as the result. A user's password is 12 (or 0000 1100 in binary).
5If the system generates r = 7, then the value of H(r, pw) returned to the system by the
user is _____.
10,000 - Answer -A hacker obtains a copy of a password file that contains 10 entries of
user ID, a unique salt, and a hash of the salted password. If the hacker knows the
hashing function (it is part of the open source OS), how many hash values does the
, hacker need to calculate to check each word in a dictionary of 1,000 common
passwords.
no imposter attempts are accepted - Answer -In a biometric user authentication system,
imposter attempts generate values between 0 and 0.5, while genuine attempts generate
values between 0.3 and 1. If the threshold is placed at 0.5 then _____.
Dn - Answer -A process p in domain _____ can read all listed objects.
D3 - Answer -Object O1 can be executed by a process in domain _____.
False - Answer -A process in D2 can remove x from A[Dn, O2].
False - Answer -A process in D3 can add x to A[Di, Oj]
2 - Answer -The shortest capability list has the length _____.
3 - Answer -The longest access list has the length _____.
Secrecy
Authenticity
Non-repudiation - Answer -What are the three main goals of cryptography?
1 - Answer -How many keys are used by secret-key cryptography?
DOG - Answer -The encryption function replaces all letters in odd positions of the
plaintext by letters shifted k positions to the right according to the English alphabet.
Letters in even positions are left unchanged. Ex: With k = 2, the letter A in any odd
position is replaced by C, the letter B is replaced by D, etc. The decryption function
reverses the substitutions. Thus k becomes the key for both encryption and decryption.
With k = 3, the plaintext corresponding to the ciphertext GOJ is _____.
2 or more - Answer -How many keys are used with public-key cryptography?
authenticity - Answer -A message authentication code (MAC) is an encrypted hash of a
larger sequence of bytes. A MAC guarantees ___ of a message.
impossible - Answer -Using secret-key cryptography instead of public-key would make
digital signatures _____.
bytes, records - Answer -Depending on the file system (FS), a file can be viewed as an
unstructured stream of ______ or a series of ________.
byte-oriented files - Answer -Read/write n bytes is applicable to
fixed-length record files - Answer -Read/write record k is applicable to
