Which of the following properties of hash algorithms are used to establish that they are cryptographically secure? (Select all that apply) a. Infeasible to discover different inputs that produce the same output b. The output length and composition are related to the hash input c. The receiver can decrypt the output to read the original plain-text message. d. It can be relatively easy to compute for small inputs but more difficult for large inputs Select the answers that are true about certificates and certificate authority hierarchies. (Select all that apply) a. Information contained in X.509 certificates can be updated by the certificate owner if necessary. b. X.509 certificates validity can only be verified if the issuing CA is online c. CA hierarchies enable validation of certificates not issued within a common organization d. CRLs are the only way to determine if a certificate is no longer valid