The following diagram shows the encryption algorithm of a modified version of CBC, which is called Plaintext Cipher Block Chaining (PCBC). a. Draw the diagram to show the decryption algorithm of PCBC. b. What is the effect to the decrypted plaintext blocks if a random error happens in one block of ciphertext, say the ith ciphertext block ci? c. What is the effect to the decrypted plaintext blocks if two ciphertext blocks, e.g., c_i and C_i + 1, are interchanged during transmission