True or False (Write your answer in the space provided before each question) (30 points) (1) Anyone can apply for a digital certificate. _(2) The main function of digital certificate is to verify that a message came from the claimed source. (3) Digital signature can be used for non-repudiation. (4) Digital certificate uses signer's private key. _(5) A hash function is a one-way function that ideally produces a unique output for each input. (6) When digitally signing the same document twice, the two digital signatures are very similar. (7) Digital certificate has an expiration date. (8) Digital certificate can be revoked. (9) Digital signature can be forged just like a hand-written signature. (10) Digital certificate contains a hash code (11) Nonrepudiation refers to the ability to protect the integrity of data. _(12) Public key can be used to deduce the private key. (13) digital signature looks exactly the same if the same document is signed by the same person _(14) Anyone can verify a digital certificate using signer's public key. (15) digital signature can be copied from one document to another. _(16) A hash code can be used to show the integrity of data during transmission or in storage. (17) A hash value can be used to protect the integrity of a document. (18) The electronic document issued by a CA that establishes an association between the individual's identity and a public key is called a digital signature. _(19) Public key encryption uses two mathematically related keys; one for encryption and the other one for decryption. (20) Very rarely two different input can have the same hash value using the same hash algorithm.
