Kripto 2, Ispit

Geometrija dlana refers to palm geometry, which is a biometric authentication method that uses the unique features and patterns of an individual's palm to verify their identity. This means that palm geometry is suitable for authentication purposes, as it can accurately identify and authenticate individuals based on the characteristics of their palm.

The correct answer is "samo potpis od CA koji je izdao serverski sertifikat" which means "only the signature of the CA that issued the server certificate". In the SSL protocol, the server sends a certificate to the client, which includes various information such as the server's public key, RSA or DH parameters, and the signature of the CA that issued the certificate. However, the master key or secret value of the server is not included in the certificate.

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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.

The given answer states that the use of passwords is not recommended. This implies that passwords are not considered secure or reliable for cryptographic algorithms. The answer suggests that alternative methods or security measures should be used instead of relying solely on passwords.

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.

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.

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.

If Eva observes a sequence Zn with k deletions in a binary wiretap channel with deletion, the parity of the selected bits is equally likely if k=0 and if k>0 Eva perfectly knows which codeword is sent (also its parity). This means that regardless of the value of k, if it is either 0 or greater than 0, Eva can accurately determine both the codeword that was sent and its parity.

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.

The correct answer is 24 bita, 3 bajta. In the RC4 algorithm, the IV (Initialization Vector) is a random value used to initialize the key stream generator. In this case, the IV size is 24 bits or 3 bytes.

In the SSL protocol, the server has the option to request the client to send its certificate. This means that the server can choose whether or not to ask the client for its certificate. It is not mandatory for the server to request the client's certificate, but it has the flexibility to do so if needed.

The correct answer is "tri biometrije, dve biometrije". This means that multimodal biometrics involves the use of three biometrics and two biometrics. It suggests that multiple forms of biometric data are being used for identification or authentication purposes.

The correct answer is "Bob autentifikuje Alisu sa simetricnim kljucem" because it states that Bob is authenticating Alice using a symmetric key. This means that Bob and Alice share the same key, and Bob can verify Alice's identity by using this key to decrypt a message or perform other authentication mechanisms.

The correct answer states that physical phenomena in sensor networks cannot be controlled by a single student in the protocol. This implies that the monitoring and control of physical phenomena in sensor networks require the collaboration and coordination of multiple students or participants in the protocol.

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.

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.

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.

The protocol shown in the picture provides mutual authentication. This means that both parties, Alice and Bob, are able to authenticate each other's identities.

The correct answer is "izdvajanje konzistentnih podataka" which means "extraction of consistent data" in English. This process refers to isolating or extracting the reliable and consistent information from a biometric source. It involves filtering out any inconsistent or unreliable data to ensure accurate and reliable biometric identification or authentication.

The correct answer is C(5, 2). This is because C(5, 2) represents the combination of choosing 2 elements from a set of 5 elements. In other words, it represents the number of ways to select 2 items from a group of 5 items without regard to their order.

The formula in the picture represents the concept of "tajnosti" or secrecy. It could be referring to a mathematical or cryptographic formula that is used to ensure the confidentiality or privacy of information. This formula may involve encryption techniques or other methods to protect sensitive data from unauthorized access or disclosure.

When Alice knows the complete Signal-to-Noise Ratio (SNR) of the main and Eve's channels, she can adjust all the parameters of the protocol and calculate the secrecy capacity of the protocol. This means that having full knowledge of the SNR allows Alice to not only set the protocol parameters but also determine the level of secrecy that can be achieved.

In the given question, the protocol for generating and distributing keys at the physical level is being discussed in the presence of a passive eavesdropper, Eva. The correct answer, "Alisa i Bob nemaju informaciju o stanju njenog kanala" translates to "Alice and Bob do not have information about the state of her channel." This means that neither Alice nor Bob have any knowledge or information about the state of Eva's channel, indicating that they are unaware of any potential eavesdropping or interference by Eva.

The capacity for secrecy in the Wiretap channel is equal to 0 if the attacker's channel is better than the legitimate parties' channels. This means that the attacker has a higher ability to intercept and decode the communication than the legitimate parties, making it impossible to maintain secrecy.

The Wiretap channel should meet the criteria of reliability and security. Reliability ensures that the channel consistently delivers the intended information without any loss or distortion. Security ensures that the channel is protected from unauthorized access and prevents any interception or tampering of the transmitted data. These criteria are important to ensure the confidentiality and integrity of the communication in the Wiretap channel.

Bezbedne kanalske kodove je moguće implementirati u drajverima bežičnih interfejs kartica. This statement explains that secure channel codes can be implemented in wireless interface card drivers.

The image depicts the concept of Rejt-Ekvivokacija regiona.

The introduction of Wiretap codes reduces the speed of transmission and the implementation complexity. This means that using Wiretap codes slows down the rate at which data is transmitted and makes it more difficult to implement the codes. However, it does not affect the capacity of the channel or the reliability and security of the transmission.

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.

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.

The correct answer is "Kljuc K je digitalno potpisan" because in protocol design, the key K is digitally signed. This means that the authenticity and integrity of the key are verified using digital signatures, ensuring that the key has not been tampered with and that it comes from a trusted source.

The image depicts the evolution of the information content of protocol participants during all phases of sequential secret key extraction.

Based on the given options, none of them accurately represent the information provided in the question. The question states "U dizajnu protokola na slici" which translates to "In the protocol design in the picture." However, none of the options mention anything about a protocol design or a picture. Therefore, none of the options are correct.

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.

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.

The correct answer is "Proces normalizacije". In the process of generating a biometric iris template, the normalization phase is depicted in the image. This phase involves standardizing the iris image to a fixed size and format, removing any distortions or variations in lighting, and aligning the iris pattern for accurate comparison and identification. The normalization process ensures that the iris template is consistent and can be effectively used for biometric authentication purposes.

LDPC kodovi su pogodni za binarni kanal sa brisanjem. Ovo znači da su ovi kodovi efikasni u otkrivanju i ispravljanju grešaka koje se javljaju kada se podaci prenose preko kanala koji može izgubiti ili obrisati neke bitove. LDPC kodovi koriste matricu parnosti sa rijetkim elementima kako bi se omogućilo otkrivanje i ispravljanje grešaka. Ovo ih čini idealnim za primjenu u situacijama gdje je moguće da se podaci izgube tokom prijenosa.

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.

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.

The number of radial vectors in the normalization process represents angular resolution.

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.

The correct answer is "izazov-odgovor protokola" because WEP (Wired Equivalent Privacy) is a security protocol used to secure wireless computer networks. It operates by using a challenge-response authentication mechanism, where the access point sends a challenge to the client device, and the client device responds with the correct answer. This process helps to verify the identity of the client device and ensure secure communication between the client and the access point.

After establishing a session in the SSL protocol, verifying authenticity involves encrypting all exchanged messages with the public key along with the secret parameters. This ensures that the messages can only be decrypted by the intended recipient, thus providing authentication and ensuring the confidentiality of the communication.

In the given scenario of Satellite scenario in the phase of advantage separation, it is stated that Eva cannot influence and have control over the post-selection phase. Additionally, Eva cannot influence Alisa and Bob's selection of the bits in which she has an advantage.

The correct answer includes three tools for cryptoanalysis of the WEP protocol: AirSnot, WEP Crack, and Aircrack. These tools are commonly used for analyzing and breaking the security of WEP encrypted networks. AirSnot is a tool used for capturing and analyzing network traffic, while WEP Crack and Aircrack are both tools specifically designed for cracking WEP encryption. By using these tools, an attacker can exploit vulnerabilities in the WEP protocol and gain unauthorized access to a network.

The correct answer states that deletion is equally likely for both 1 and 0 in a binary wiretap channel with deletion. This means that when transmitting data through this channel, there is an equal chance of either a 1 or a 0 being deleted.

The correct answer is "Alisa moze preneti Bobu skvencu lokalno generisanog kriptografskog kljuca K." This means that Alisa can transmit the sequence of locally generated cryptographic key K to Bob.

Klijenti Kerberos protokola koriste master tiket koji je generisan u inicijalnoj fazi za pristup mrežnom resursu.

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.

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.

The correct answer is "Finalni korak u sekvencijalnom protokolu izdvajanja tajnog kljuca izmedju Alise i Boba." This means that strengthening privacy in a satellite scenario is the final step in the sequential protocol for extracting the secret key between Alice and Bob.

The correct answer is "Aplikativni." End-to-end encryption is a method of securing communication where the data is encrypted on the sender's device and decrypted on the receiver's device. This encryption and decryption process occurs at the application level, specifically within the application layer of the network protocol stack. Therefore, end-to-end encryption belongs to the application layer or the "Aplikativni" layer.

The correct answer states that Trudi cannot obtain the key if she has access to Alice's computer and she cannot decrypt all the recorded ciphers using a single key K. This implies that perfect secrecy (PFS) is achieved because even if Trudi has access to the computer or the recorded ciphers, she cannot retrieve the key or decrypt the ciphers without the specific key for each cipher. Additionally, the answer does not mention anything about Trudi being unable to learn the private key or encrypt the recorded cipher later, so those statements are not relevant to the concept of perfect secrecy.

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.

The correct answer is "Javnog kljuca" (Public key). Verification of a digital signature is done using the public key. In a public key cryptography system, a digital signature is created using the private key of the signer and can be verified using the corresponding public key. The public key is available to anyone who wants to verify the signature, while the private key is kept secret by the signer. By using the public key, the recipient can verify the authenticity and integrity of the digital signature.

Pojačavanje privatnosti podrazumeva dogovor ili sporazum koji se odnosi na determinističku funkciju. Deterministička funkcija je funkcija koja za svaki ulaz daje tačno određen izlaz, što znači da se može precizno odrediti kako će se podaci koristiti i ko će imati pristup tim podacima. Ovaj dogovor se postiže kako bi se osigurala privatnost podataka i sprečilo neovlašćeno korišćenje ili pristupanje podacima.

In the protocol for generating and distributing keys at the physical level, knowing the channel state is a prerequisite for achieving perfect security. This means that in order to achieve perfect security in the protocol, it is necessary to have knowledge of the state of the channel.

The role of the Gabor wavelet is to eliminate noise from the signal.

This answer suggests that in the context of semi-quantum coding based on cosets, Alisa generates a random sequence U of length K, about which both Bob and Eva have no information.

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.

The correct answer is that it is not possible to directly apply classical cryptanalytic methods on a wiretap channel, or their modification would require a significant increase in the complexity of the attack. This means that traditional methods of analyzing and breaking encryption would not be effective or would require extensive modifications to work on a wiretap channel.

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.

The correct answer is "Izdvajanje irisa sa digitalne fotografije" (Extraction of iris from a digital photograph). This is because iris segmentation refers to the process of isolating the iris region from an image, specifically from a digital photograph.

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.

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.

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.

CRC (cyclic redundancy check) is used instead of a salt in a cryptographic key. A salt is a random value added to a password before it is hashed, to prevent dictionary attacks and rainbow table attacks. However, in the context of a cryptographic key, a salt may not be necessary or appropriate. Instead, a CRC can be used to verify the integrity of the key. CRC is a technique commonly used in error detection, where a checksum is calculated and appended to the data. Upon receiving the data, the checksum is recalculated and compared to the appended value to check if any errors occurred during transmission.

SSL (Secure Socket Layer) je protokol koji pruža sigurnu komunikaciju između klijenta i servera. On se nalazi na transportnom sloju u mrežnom modelu OSI, što znači da se koristi za sigurnu razmjenu podataka između aplikacija koje se koriste na klijentu i serveru. Transportni sloj je odgovoran za pouzdanu isporuku podataka između krajnjih tačaka u mreži, što čini SSL pogodnim slojem za implementaciju sigurne komunikacije.

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The given code fragment represents the algorithms for exchanging symmetric keys.

The compression before encryption in the SSL protocol is not supported due to performance reasons. Compression can potentially reduce the size of the data being transmitted, making it faster to send and receive. However, compressing data before encryption can also introduce security vulnerabilities. Attackers could potentially exploit patterns in the compressed data to gain insights into the encrypted information. Therefore, to prioritize security, compression is not supported in the SSL protocol.

The statement suggests that the fact that broadcasting from different devices and positions always produces different channel impulse responses can be a sufficient criterion for rejecting false representation. This means that if the impulse responses vary, it indicates that the representation is not genuine.

The wiretap codes replace existing conventional channel codes and modulation schemes, ensuring reliability.

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.

The complete process for generating a biometric iris template involves the following stages: coding, segmentation, and normalization. Coding refers to the process of converting the iris image into a digital representation that can be easily processed. Segmentation involves identifying and extracting the iris region from the overall image. Normalization is the step where the extracted iris region is transformed into a standardized format, ensuring consistency across different iris images. These three stages together form the complete process of generating a biometric iris template.

The given answer includes three cryptographic protocols: SSL, Kerberos, and GSM. SSL (Secure Sockets Layer) is a widely used protocol for securing internet connections and encrypting data. Kerberos is a network authentication protocol that provides secure communication over a non-secure network. GSM (Global System for Mobile Communications) is a standard for mobile communication that includes encryption algorithms for secure voice and data transmission. These protocols are commonly used in various applications to ensure secure and encrypted communication.

The correct answer is "Link podataka." The Link podataka layer is responsible for the physical transmission of data between network nodes and includes protocols such as Ethernet. It ensures reliable and error-free communication over the physical medium, such as cables or wireless connections. The WPA (Wireless Protected Access) protocol is a security protocol that operates at the Link podataka layer to provide secure access to wireless networks.

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.

The correct answer suggests that resistance in protective protocols requires the ability to function even when the environment changes and remain stable during an attack. This means that the protocols should be able to adapt to different conditions and continue to operate effectively. Additionally, they should be able to withstand attacks without compromising their stability.

The correct answer is that the randomized code word X reveals very little or no information to Eve about the transmitted message M. This means that even if Eve intercepts the code word, she will not be able to gain much or any information about the original message being sent. This is an important property in secure communication systems, as it helps to protect the confidentiality of the message from unauthorized parties.

The correct answer is Hafov algoritam. Hafov algoritam, also known as Hough algorithm, is commonly used in iris segmentation. This algorithm helps in detecting the circular shape of the iris and extracting it from the rest of the eye image. By using the Hough algorithm, the boundaries of the iris can be accurately identified, which is crucial for various applications such as biometric identification systems.

The correct answer is that the satellite scenario is impossible if the error of the attacker is smaller than the error of the legitimate participants in the protocol. This means that even if the attacker makes a smaller error, it is still not possible to achieve the satellite scenario.

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.

In the given question, the correct answer is "Eva moze kompromitovati izlozene bezbednosne mehanizme". This means that Eva can compromise the exposed security mechanisms. The other provided options are not possible because Eva can falsely represent herself, which means that all previous scenarios are not possible.

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.

The correct answer is a combination of three options: Minimizacija propusnog opsega, Minimizacija racunarskih zahteva posebno u pogledu skupih operacija vezanih za javne kljuceve, and Minimizacija kasnjenja. This means that efficiency in protective protocols involves reducing the bandwidth usage, minimizing computational requirements, especially for expensive operations related to public keys, and minimizing delays. These measures ensure that the protocols can effectively handle attacks, adapt to changing environments, and perform efficiently in terms of resource utilization and response time.

The correct answer is "Razmenu sesijskog kljuca preko javnog kljuca". This is because the question asks what the "prokol" represents in the picture. The term "razmenu sesijskog kljuca preko javnog kljuca" translates to "exchange of session key using public key", which is a cryptographic protocol used for secure communication. The other option, "Razmenu sesijskog kljuca bez uzajamne autentifikacije", translates to "exchange of session key without mutual authentication", which is not mentioned in the question. Therefore, the correct answer is the option that is mentioned in the question.

The correct answer is "Binarni komunikacioni wiretap kanal sa brisanjem" and "Kanal za bezbedno komuniciranje sa sumom". This suggests that the image represents a binary communication wiretap channel with erasure and a channel for secure communication with noise.

If the datagrams are already protected by cryptographic methods, secure channel codes actually prevent Eve from obtaining the cipher with errors. This means that secure channel codes ensure that Eve cannot obtain the cipher with any errors, ensuring the integrity and accuracy of the transmitted message.

The correct answer is that clients in the Kerberos protocol have encrypted communication in the network and share the key with the KDC (Key Distribution Center). This means that the clients use encryption to ensure that their communication cannot be intercepted or read by unauthorized parties. Additionally, they share the key with the KDC, which is responsible for issuing tickets and granting access to network resources based on authentication.

The correct answer explains that the U channel model for secret key agreement is used not only for communication but also for generating randomness. This means that in addition to facilitating communication between parties, the U channel also plays a role in generating random values that are necessary for secure key generation.

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.

Generating a shared secret key at the physical level requires two things: redesigning the driver for the wireless interface card and redesigning at the link layer. These two actions are necessary to ensure that the wireless interface card and the link layer are capable of generating and exchanging the shared secret key securely. The other options, such as redesigning at all layers and making modifications to the security and communication components of the operating system, are not specifically mentioned as requirements for generating the shared secret key at the physical level.