1.
U protokolu za autentifikaciju sa javnim kljucem:
Correct Answer
C. Koristi se dva para kljuceva za siforvanje i potpisivanje
Explanation
In the protocol for public key authentication, two pairs of keys are used for encryption and signing. This means that one pair of keys is used for encrypting the data and another pair of keys is used for digitally signing the data. By using two pairs of keys, the protocol ensures both confidentiality and authenticity of the data being transmitted.
2.
U Wynerovom wiretap kanalu, performanse pouzdanosti prenosa se mere:
Correct Answer
A. Prosecnom verovatnocom greske dekodovanja
Explanation
In the Wyner wiretap channel, the performance of transmission reliability is measured by the average probability of decoding error. This means that the measure of how often errors occur during the decoding process determines the reliability of the transmission. The other options, such as the degree of compression, leakage, and equivocation, are not relevant to measuring the performance of reliability in this specific context.
3.
Ukoliko se u autentifikaciji koristi simetricni kljuc za autentifikaciju, tada je moguc;
Correct Answer
C. MiM napad
Explanation
If a symmetric key is used for authentication, it is vulnerable to a MiM (Man-in-the-Middle) attack. In this type of attack, an attacker intercepts the communication between the two parties and impersonates each party to the other, making it appear as though they are communicating directly. By doing so, the attacker can gain unauthorized access, manipulate the communication, or steal sensitive information. This vulnerability arises because the symmetric key used for authentication is shared between the two parties and can be intercepted and used by the attacker to impersonate one or both parties.
4.
Izabrati fizicke fenomene koje mogu da monitorisu uredjaj u sezonskim mrezama:
Correct Answer(s)
A. Pristisak
B. Temperatura
Explanation
The physical phenomena that can be monitored in seasonal networks are pressure and temperature. These variables are commonly measured and monitored in various systems and devices to ensure their proper functioning and to prevent any potential issues or failures. The other options, such as key length and radius, do not relate to physical phenomena that can be monitored in this context.
5.
Model kanala za dogovor o tajnom kljucu podrazumeva :
Correct Answer
C. Da Bob i Eva observiraju izlaze diskretnog kanala bez memorije ciji je ulaz pod kontrolom Alise
Explanation
The correct answer is that Bob and Eva observe the outputs of a discrete memoryless channel whose input is under the control of Alice. This means that Alice is the one who controls the input of the channel, while Bob and Eva observe the outputs.
6.
Procena impulsnog odziva kanala vrsi se:
Correct Answer
B. Slanjem trening sekvenci
Explanation
The correct answer is "Slanjem trening sekvenci" which translates to "Sending training sequences" in English. This suggests that the evaluation of the impulse response of the channel is done by transmitting specific sequences of signals known as training sequences. These training sequences are used to analyze the behavior and characteristics of the channel, allowing for a better understanding of its response to different signals.
7.
Autentifikacija preko mreze je daleko kompleksnija, razlog tome je:
Correct Answer(s)
B. Napadac moze da ponovo reprodukuje poruku
D. Napadac moze pasivno da observira poruku
F. Moguci su i aktivni napadi (umetanje, brisanje, promena poruke)
Explanation
Authentication over the network is far more complex due to several reasons. An attacker can possess the same private key, allowing them to impersonate the legitimate user. Additionally, the attacker can passively observe the message, gaining access to sensitive information. Furthermore, both passive attacks (such as message insertion, deletion, and modification) and active attacks (such as message tampering) are possible. These factors contribute to the increased complexity and vulnerability of network authentication.
8.
Veliki problem u WEP protokolu predstavlja:
Correct Answer(s)
B. Kratak kljuc
C. Implementacija RC4 algoritma
Explanation
The correct answer is "Kratak kljuc, Implementacija RC4 algoritma". The WEP protocol has a vulnerability in its implementation of the RC4 algorithm, which makes it susceptible to attacks. Additionally, the use of a short key in WEP encryption makes it easier for attackers to crack the encryption. These two factors contribute to the major problem with the WEP protocol.
9.
Wajnerov Wire-Tap kanal je protokol za razmenu:
Correct Answer
D. Simetricnih kljuceva
Explanation
The correct answer is "Simetricnih kljuceva" (Symmetric keys). This suggests that the Wajnerov Wire-Tap channel is a protocol used for exchanging symmetric keys. Symmetric key encryption uses the same key for both encryption and decryption, making it faster and more efficient for data exchange.
10.
Izaberite tacnu tvrdnju:
Correct Answer
B. Eva poznaje postupak kodovanja, kao i Bob i Alisa. Ne postoje nikakvi unapred uspostavljeni tajni kljucevi
Explanation
The correct answer is "Eva poznaje postupak kodovanja, kao i Bob i Alisa. Ne postoje nikakvi unapred uspostavljeni tajni kljucevi." This means that Eva, Bob, and Alisa all know the encoding process and there are no pre-established secret keys.
11.
Emitovanje sa drugih uredjaja i sa drugih pozicija uvek
Correct Answer
C. Daje razlicite implusne odzive kanala
Explanation
This statement suggests that broadcasting from different devices and positions always results in different impulse responses of the channel. This means that the channel's response to a sudden change or impulse in the input signal will vary depending on the device and position from which it is broadcasted.
12.
U fazi kodovanja biometrije irisa koristi se transformacija:
Correct Answer(s)
A. 2D Gabor vejvlet
B. 1D Gabor vejvlet
Explanation
The correct answer is 2D Gabor vejvlet and 1D Gabor vejvlet. In the coding phase of iris biometrics, a transformation called Gabor wavelet is used. Gabor wavelets are mathematical functions that are applied to images to extract features. In the case of iris biometrics, both 2D and 1D Gabor wavelets are utilized to transform the iris image and extract relevant information for identification and authentication purposes.
13.
Jednostavan metod za razbijanje WEP protokola je:
Correct Answer
A. Statisticka analiza sifrata
Explanation
Statistička analiza šifre je jednostavan metod za razbijanje WEP protokola. Ovaj metod se zasniva na analizi statističkih karakteristika šifre kako bi se otkrili uzorci i slabosti u njoj. Kroz analizu statističkih podataka, moguće je otkriti ključeve ili druge informacije koje omogućavaju dešifrovanje šifre.
14.
Autentifikacija moze biti zasnovana na necemu sto:
Correct Answer(s)
B. Jesmo
D. Imamo
E. Znate
Explanation
Authentication can be based on something we are (biometric characteristics like fingerprints or facial recognition), something we have (like a physical token or a smart card), or something we know (like a password or PIN). In this case, "jesmo" (we are) and "imamo" (we have) are both valid options for authentication methods. "Znate" (you know) is not a valid option for authentication as it refers to someone else knowing something about us, rather than a personal characteristic or possession.
15.
PFS podrazumeva:
Correct Answer
C. Sesijski kljuc koji se koristi jednokratno, a zatim trajno unistava
Explanation
PFS (Perfect Forward Secrecy) refers to the use of a session key that is used only once and then permanently destroyed. This ensures that even if the session key is compromised in the future, it cannot be used to decrypt past communications. By using a session key that is destroyed after use, PFS provides an additional layer of security and protection against potential attacks on encrypted communications.
16.
Ukoliko server opciono zahteva od klijenta sertifikat, to znaci da je zahtevana:
Correct Answer
B. Obostrana autentifikacija
Explanation
If the server optionally requests a client certificate, it means that mutual authentication is required. This means that both the server and the client need to authenticate each other's identities using certificates. This helps ensure that both parties are who they claim to be before establishing a secure connection.
17.
Wiretap kanal Cn:
Correct Answer
A. Moze se smatrati procedurom izdvajanja zajednickog tajnog kljuca
Explanation
The correct answer is "Moze se smatrati procedurom izdvajanja zajednickog tajnog kljuca" because a wiretap channel is a method of extracting a shared secret key.
18.
Promena kljuca u WEP protokolu je:
Correct Answer
C. Neautomatizovan proces
Explanation
The correct answer is "Neautomatizovan proces" (Non-automated process). In the WEP protocol, changing the key is not done automatically but requires manual intervention. This means that the network administrator or user needs to manually update the key whenever they want to change it. It is not dependent on the network administrator or the cost of the WiFi router, but rather on the manual action of changing the key.
19.
Kod protokola za generisanja i distribuciju kljuceva na fizickom nivou:
Correct Answer
B. Eva ima mogucnost da salje laznu sliku SNR-a u njenom kanalu
Explanation
The correct answer states that Eva has the ability to send a fake image of SNR (Signal-to-Noise Ratio) in her channel. This implies that Eva can manipulate the SNR protocol for generating and distributing keys at the physical level.
20.
Kapacitet tajnosti u Wiretap kanalu predstavlja:
Correct Answer
A. Maksimalnu brzinu prenosa pri kojoj su ispunjena oba kriterijuma, pouzdanost i bezbednost
Explanation
The correct answer is "Maksimalnu brzinu prenosa pri kojoj su ispunjena oba kriterijuma, pouzdanost i bezbednost." This means that the capacity of secrecy in the Wiretap channel represents the maximum transmission speed at which both criteria, reliability and security, are fulfilled.
21.
Sumovi koji postoje u iris kodu, nastali su usled:
Correct Answer(s)
A. Rotacije oka u ocnoj duplji
B. Rotacije kamere
C. Loseg kvaliteta senzora
F. Distrozije zenice usled promene osvetljenja
Explanation
The correct answer is a combination of factors that contribute to the existence of noise in iris code. These factors include rotations of the eye in the eye socket, rotations of the camera, poor sensor quality, distortions of the pupil due to changes in lighting, and variations in iris size.
22.
Verifikacijom potpisa na sertifikatu istovremeno se:
Correct Answer
B. Identifikuje vlasnik privatnog kljuca preko koga je nastao potpis
Explanation
The correct answer is "Identifikuje vlasnik privatnog kljuca preko koga je nastao potpis." This means that the verification of the signature on the certificate simultaneously identifies the owner of the private key from which the signature originated.
23.
Napad zasnovan na ponavljanju poruke u autentifikacionim protkolima, moguce je spreciti sa:
Correct Answer
A. Izazovom
Explanation
The correct answer is "izazovom". In authentication protocols, a replay attack can be prevented by using a challenge-response mechanism. By sending a unique challenge to the client, the server can verify that the response received is not a replay of a previous message. This ensures that each authentication attempt is fresh and prevents attackers from intercepting and replaying previous messages to gain unauthorized access.
24.
Izaberi sve faze Satelitskog scenarija:
Correct Answer(s)
B. Usaglasavanje informacije
D. Destilacija prednosti
E. Pojacavanje privatnosti
Explanation
The correct answer is Usaglasavanje informacije, Destilacija prednosti, Pojacavanje privatnosti. These phases are all related to information management and security in a satellite scenario. Usaglasavanje informacije refers to the process of coordinating and synchronizing information between different components or systems. Destilacija prednosti involves extracting the most valuable or relevant information from a larger set of data. Pojacavanje privatnosti focuses on enhancing privacy and ensuring the confidentiality of information. These phases are important in ensuring the smooth operation and security of satellite systems.
25.
U bezicnim senzorskim mrezama, uredjaji mogu da monitrisu:
Correct Answer
A. Fizicke fenomene
Explanation
In wireless sensor networks, devices can monitor physical phenomena. This means that the devices are capable of collecting data and measuring various physical parameters such as temperature, humidity, pressure, motion, and light intensity. By monitoring these physical phenomena, the devices can provide valuable information about the environment and enable applications such as environmental monitoring, healthcare monitoring, and industrial monitoring.
26.
Ocekivano rastojanje za dva slucajno generisana binarna niza je:
Correct Answer
D. 0,5
Explanation
The expected distance for two randomly generated binary sequences is 0.5. This means that on average, the two sequences will differ in exactly half of their positions.
27.
Sesijski kljuc je:
Correct Answer
C. Simetricni tajni kljuc za jednu komunikaciju
Explanation
The correct answer is "Simetricni tajni kljuc za jednu komunikaciju" (Symmetric secret key for one communication). This means that a symmetric secret key is used for one communication session between participants. This key is shared between the sender and receiver and is used for both encryption and decryption of the messages exchanged during the communication session.
28.
Pouzdanost u Wiretap kanalu oznacava:
Correct Answer
C. Da Bob treba da dekoduje Alisinu poruku poslatu po kanalu C1
Explanation
The correct answer is "Da Bob treba da dekoduje Alisinu poruku poslatu po kanalu C1" which translates to "Bob needs to decode Alice's message sent through channel C1". This answer is the only option that is relevant to the concept of reliability in a wiretap channel. The other options do not mention reliability or the decoding of messages.
29.
Jedini uslov za bezbedan rad Wajnerovog Wire-Tap kanala je:
Correct Answer
C. Da napadac prima zasumljenu verziju signala legitimnog prijemnika
Explanation
The only condition for the secure operation of the Wajner Wire-Tap channel is that the attacker receives a noisy version of the legitimate receiver's signal.
30.
U protokolu za autentifikaciju sa javnim kljucem:
Correct Answer
B. Trudi moze da natera Alisu da desifruje bilo sta!
31.
Svaki tiket u Kerberos protokolu je sifrovan sa:
Correct Answer
D. Simetricnim kljucem KDC-a
Explanation
In Kerberos protocol, each ticket is encrypted with the symmetric key of the Key Distribution Center (KDC). The KDC is responsible for issuing tickets and authenticating clients. Using a symmetric key for encryption ensures that both the KDC and the client can decrypt and verify the ticket. This symmetric key is shared between the KDC and the client, allowing secure communication between them.
32.
Bezbednost u Wiretap kanalu oznacava:
Correct Answer
B. Da Evina informacija o poruci M, mora da tezi nuli, kada duzna bloka raste
Explanation
The correct answer states that security in the Wiretap channel means that Eve's information about the message M must approach zero as the block length increases. This means that as the size of the blocks of the message increases, Eve should have less and less information about the actual content of the message. This ensures that the message remains secure and cannot be easily intercepted or decoded by an unauthorized party.
33.
Autentifikacija preko Kerberos protokola zasnovana je na:
Correct Answer
D. Simetricnom kljucu
Explanation
The correct answer is "simetricnom kljucu" which translates to "symmetric key" in English. This means that authentication through the Kerberos protocol is based on the use of a symmetric key. In symmetric key cryptography, the same key is used for both encryption and decryption. This key is shared between the client and the server, allowing them to securely authenticate each other.
34.
Protokoli za uzajamnu autentifikaciju su simetricnim kljucevima:
Correct Answer
D. Nisu uvek bezbedni, ponekad je moguc napad
Explanation
Protocols for mutual authentication are not always secure because there is a possibility of an attack. This means that even if symmetric keys are used, there are still potential vulnerabilities that can be exploited by attackers. Therefore, the statement "Nisu uvek bezbedni, ponekad je moguc napad" (They are not always secure, sometimes an attack is possible) is the correct answer.
35.
Izabrati faze za izdvjanje tajnog kljuca:
Correct Answer(s)
A. Izjednacavanje informacija
B. Raspodela slucajnosti
F. Pojacavanje privatnosti
G. Izdvjanje prednosti
36.
Uloga wiretap kodova je:
Correct Answer
B. Zamena postojecih konvencionalnih kanalskih kodova i modulacionih sema, koje obebedjuju pouzdanost
Explanation
The wiretap codes replace existing conventional channel codes and modulation schemes, ensuring reliability.
37.
Postupak kreiranja digitalnog potpisa se sastoji iz dve faze. U drugoj fazi:
Correct Answer
A. Primenjuje se odgovarajuci algoritam (RSA) da bi se dobijeni otisak iz prve faze sifrovao privatnim kljucem
Explanation
In the second phase of creating a digital signature, the correct answer states that the obtained fingerprint from the first phase is encrypted with the private key using the appropriate algorithm (RSA). This step ensures the security and authenticity of the digital signature by encrypting it with the private key, making it difficult for anyone without the corresponding public key to tamper with or forge the signature.
38.
Kod protokola za generisanje i distribuciju kljuceva na fizickom nivou, u slucaju da je Eva pasivni prisluskivac:
Correct Answer
A. Alisa i Bob mogu da se oslone samo na konzervativne procene, zasnovane na pretpostavljenoj udaljenosti Evinih antetna i njihovog kvaliteta
Explanation
In the given question, the correct answer is "Alisa i Bob mogu da se oslone samo na konzervativne procene, zasnovane na pretpostavljenoj udaljenosti Evinih antetna i njihovog kvaliteta" (Alice and Bob can rely only on conservative estimates based on the assumed distance of Eva's antennas and their quality). This means that in the protocol for generating and distributing keys at the physical level, if Eva is a passive eavesdropper, Alice and Bob can only make conservative estimations about the distance between Eva's antennas and their quality. They cannot rely on any other information or assumptions provided in the options.
39.
Izaberite biometrijske izvore?
Correct Answer(s)
A. Iris
B. Glas
E. Lice
H. Otisak prsta
Explanation
The correct answer includes biometric sources that can be used for identification or authentication purposes. Iris, glas (voice), lice (face), and otisak prsta (fingerprint) are all commonly used biometric sources. These sources provide unique characteristics that can be measured and compared to stored data to verify a person's identity.
40.
Izaberite tacnu tvrdnju:
Correct Answer
A. Kodovi u wiretap kanalu ne zahtevaju prethodno razmenjen tajni kljuc
Explanation
The statement says that codes in the wiretap channel do not require a previously exchanged secret key. This means that the codes used in the wiretap channel can be transmitted without the need for a secret key that has been exchanged beforehand.
41.
Sa aspekta implementacije WEP protokol predstavlja:
Correct Answer
D. Pogresnu implementaciju pseudo One-time pad algoritma
Explanation
The correct answer is "pogresnu implementaciju pseudo One-time pad algoritma". This means that the implementation of the WEP protocol is incorrect because it uses a flawed version of the pseudo One-time pad algorithm. The One-time pad algorithm is a secure encryption method that uses a random key that is as long as the message being encrypted. However, the WEP protocol's implementation of this algorithm is flawed, making it susceptible to security vulnerabilities.
42.
Sta je podrazumevano pod fazom za normalizaciju irisa?
Correct Answer
A. Transformaciju iris regiona u fiksne dimenzije koje su unapred poznate
Explanation
The default phase for iris normalization refers to transforming the iris region into fixed dimensions that are predetermined. This means that regardless of the distance or variation in dimensions of the iris region, it will be transformed into a consistent size that is already known in advance.
43.
U fazi pojacavanja privatnosti:
Correct Answer
A. Alisa i Bob generisu zajednicku kracu sekvencu bita o kojoj Eva nema nikakvu informaciju
Explanation
In the phase of increasing privacy, Alisa and Bob generate a shorter bit sequence that Eva has no information about. This means that Alisa and Bob are able to generate a shared secret that is unknown to Eva, enhancing their privacy.
44.
Kerberos protokol za N broj korisnika generise:
Correct Answer
C. N kljuceva
Explanation
The Kerberos protocol generates N keys for N number of users. This means that for each user, there is a unique key generated, resulting in a total of N keys.
45.
Autentifikacija moze biti zasnovana na:
Correct Answer(s)
A. Biometriji
D. Pametnim karticama
E. Lozinkama
Explanation
Authentication can be based on biometrics, smart cards, and passwords. Biometrics refers to the use of unique physical or behavioral characteristics, such as fingerprints or facial recognition, to verify a person's identity. Smart cards are small electronic devices that store and process data, often used for authentication purposes. Passwords are secret codes or phrases that individuals use to prove their identity. Therefore, these three options can all be used for authentication purposes.
46.
Kod protokola za generisanje i distribuciju kljuceva na fizickom nivou, problem autentifikacije je moguce resiti:
Correct Answer(s)
A. Javnim kljucem (PKI)
D. Merenjem ili pamcenjem impulsnog odziva kanala, pod uslovom da se u pocetnoj fazi kada se estimira impulsni odziv, ima poverenja u njihovu autenticnost
Explanation
The correct answer is Javnim kljucem (PKI) and Merenjem ili pamcenjem impulsnog odziva kanala, pod uslovom da se u pocetnoj fazi kada se estimira impulsni odziv, ima poverenja u njihovu autenticnost. This means that the authentication problem in the protocol for generating and distributing keys at the physical level can be solved by using a public key infrastructure (PKI) and by measuring or storing the impulse response of the channel, under the condition that there is trust in their authenticity during the initial estimation phase.
47.
Na slici je prikazan princip:
Correct Answer
C. Pojacavanja privatnosti
Explanation
The correct answer is "Pojacavanja privatnosti" (Enhancing privacy). This is because the image represents a concept or principle related to enhancing privacy. Without further context or information about the image, it is difficult to provide a more specific explanation.
48.
Na slici je prikazan:
Correct Answer
C. Vajnerov Wire-Tap kanal
Explanation
The correct answer is Vajnerov Wire-Tap kanal. The given options are all related to encryption protocols and channels. The Vajnerov Wire-Tap kanal is a specific type of channel that is used in cryptography. It is designed to provide secure communication between two parties, while also allowing a third party to eavesdrop on the communication without being able to decipher the encrypted messages. This channel is often used in scenarios where a government or other authorized entity needs to monitor communication for security purposes.
49.
Na slici je prikazan:
Correct Answer
D. Dogovor o tajnom kljucu na osnovu modela izvora i kanala
Explanation
The correct answer is "Dogovor o tajnom kljucu na osnovu modela izvora i kanala." This means that the agreement for a secret key is based on the model of the source and the channel. In other words, the secret key is generated using information about how the source data is transmitted through the channel. This method ensures that the key is secure and can be used for encryption and decryption between the sender and receiver.
50.
U protokolu na slici:
Correct Answer(s)
C. Alisa mora da zna lozinku
E. Bob mora da zna lozinku
Explanation
The correct answer is that both Alisa and Bob must know the password. This can be inferred from the given options where it is stated that Alisa must know the password and Bob must know the password. Both statements are true according to the options provided.