Computer Security questions
Chapter 3 1. A phonetic password generator picks two segments randomly for each six-letter password. The form of each segment is CVC (consonant, vowel, consonant), where v= e, I, o, u> and CV. a. What is the total password population? b. What is the probability of an adversary guessing a password correctly? 2. Explain why, for the biometric authentication protocols, the biometric capture device is authenticated in the case of static biometric but not authenticated for a dynamic biometric. Chapter 4 1. UNIX treats file directories in the same fashion as files; that is, both are defined by the same type of data structure, called an inode. As with files, directories include a nine-bit protection string. If care is not taken, this can create access control problems. For example, consider a file with protection mode 644 (octal) contained in a directory with protection mode 730 How might the file be compromised in this case? 2. For the DAC model discussed in Section 4.3, an alternative representation of the protection state is a directed graph. Each subject and each object in the protection state is represented by a node (a single node is used for an entity that is both subject and object). A directed line form a subject to an object indicates an access right, and the label on the link defines the access right. a. Draw a directed graph that represented to the access b. Draw a directed graph that represented to the access e. Is there a one-to-one correspondence between the matrix of Figure 4.3a matrix of Figure 4.4 directed graph representation and the access matrix representation? Explain your answer Chapter 3 1. A phonetic password generator picks two segments randomly for each six-letter password. The form of each segment is CVC (consonant, vowel, consonant), where v= e, I, o, u> and CV. a. What is the total password population? b. What is the probability of an adversary guessing a password correctly? 2. Explain why, for the biometric authentication protocols, the biometric capture device is authenticated in the case of static biometric but not authenticated for a dynamic biometric. Chapter 4 1. UNIX treats file directories in the same fashion as files; that is, both are defined by the same type of data structure, called an inode. As with files, directories include a nine-bit protection string. If care is not taken, this can create access control problems. For example, consider a file with protection mode 644 (octal) contained in a directory with protection mode 730 How might the file be compromised in this case? 2. For the DAC model discussed in Section 4.3, an alternative representation of the protection state is a directed graph. Each subject and each object in the protection state is represented by a node (a single node is used for an entity that is both subject and object). A directed line form a subject to an object indicates an access right, and the label on the link defines the access right. a. Draw a directed graph that represented to the access b. Draw a directed graph that represented to the access e. Is there a one-to-one correspondence between the matrix of Figure 4.3a matrix of Figure 4.4 directed graph representation and the access matrix representation? Explain your
