Bob wants to store a piece of data DDD on the blockchain, en…
Bob wants to store a piece of data DDD on the blockchain, ensuring its integrity. To do so, he generates a hash H(D)H(D), which is the cryptographic hash of the data DD. The hash function HH satisfies the following properties: Preimage Resistance: Given a hash hh, it is computationally infeasible to find DD such that H(D)=hH(D) = h. Collision Resistance: It is computationally infeasible to find two different data sets D1≠D2D_1 \neq D_2 such that H(D1)=H(D2)H(D_1) = H(D_2). Now, consider that Bob stores (D,H(D))(D, H(D)) on the blockchain, and later, Alice retrieves this data. Alice wants to verify the integrity of DD. The integrity check is given by: Integrity Check =True if H(D)==H(D′)Where D′D’ is the retrieved data and H(D′)H(D’) is the hash of the retrieved data. What must Alice check to ensure the integrity of the data?