(a)How does cryptography protect the security and privacy in blockchain transactions from hackers? (Using the concepts of private key, public key, hash, digital signatures)

(b) You want to send a contract C to Company X. Is it safe (i.e. without the possibility of being hacked) if you send it (i.e. Contract C) with the hash value of Contract C to Company X in Blockchain? Substantiate your answer. (c) Contract C is a long document. Is it safe (i.e. without the possibility of being hacked) and feasible if you send a contract C with the senders digital signature to Company X in Blockchain? Please explain. (d) If the answer to part (c) is no, suggest a better solution.