Check whether the given schedule S is conflict serializable or not- S : R1(A) , R2(A) , R1(B) , R2(B) , R3(B) , W1(A) , W2(B), W3(B),W3(A). S: R2(X) , W3(X) commit, W1(X) Commit, W2(Y), R2(Z) Commit, R4(X), R4(Y), R5(Z), W1(Z). S: R4(A), R2(A), R3(A), W1(B), W2(A), R3(B), W2(B), W3(A), W4(B)

Question 1. Let H: {0,1}* → {0, 1}" be a hash function that achieves the one-way and collision resistance security properties. (b). Show that the new function H' achieves collision resistance. Suppose that we want to use H for the deployment of a password-based user authentication mechanism that is a variant of the standard password hashing mechanism as follows: when loading a new password P selected by the user with ID U, instead of choosing a random salt, the password P is hashed. Then, the n-bit digest H(P) and password P serve as inputs to produce a fixed-length hash code. Namely, the information that is stored in the password file is the triple (U, H(P), H(H(P)||P)). During password verification for user ID U, the system receives a password P* and (i) computes H(P*), (ii) computes H(H(P*)||P*), and (iii) checks if H(H(P*)||P*) matches the value H(H(P)||P) that is stored for U. 1 Does the aforementioned mechanism provide protection against offline dictionary attacks? Justify your…

Consider the following two transactions: T1-R(B), W(B), R(C), R(A) T2-R(B). W(B) Say that sharing lock, exclusive lock, and unlock actions are inserted by the scheduler, resulting in the following annotated transactions: T1= X(B), R(B), W(B), S(C), R(C), S(A), U(B), R(A), U(C), U(A) T2-X(B), R(B), W(B), U(B) Cascading rollback is not possible for the above schedule. True False