Hashing, Digital Signatures, and Digital Certificates CASENET Practice Questions (Page 8)

Questions 36–40

1. 36foundation · easy

   Which component of a digital certificate is used to verify the certificate's authenticity?

   • AThe certificate authority's digital signature
   • BThe certificate's serial number
   • CThe certificate holder's public key
   • DThe certificate holder's private key
   Reveal Solution Discussion Select an answer first
2. 37application · medium

   A company sends purchase orders to a supplier via email. The supplier wants to be sure that the orders are genuinely from the company and have not been altered. The company decides to use digital signatures. Which property does a digital signature provide that a simple hash does not?

   • AAvailability: the document is always accessible to authorized users.
   • BConfidentiality: the document is encrypted and cannot be read by unauthorized parties.
   • CNon-repudiation: the signer cannot deny having signed the document.
   • DCompression: the document is smaller and easier to transmit.
   Reveal Solution Discussion Select an answer first
4. 38expert · hard

   A .NET developer is implementing a document signing feature. The documents can be large (up to 100 MB). The developer wants to sign them efficiently without loading the entire document into memory. Which approach should the developer use?

   • AUse a hash-based signature: hash the document in a streaming manner, then sign only the hash.
   • BSign the document's file name and metadata instead of the content.
   • CCompress the document first, then sign the compressed data.
   • DLoad the entire document into a byte array and sign it directly.
   Reveal Solution Discussion Select an answer first
5. 39expert · hard

   A .NET developer is implementing a file integrity monitoring system. The system must detect unauthorized modifications to configuration files. The security team requires that the integrity check be resistant to an attacker who can modify both the files and the stored hash. Which approach should the developer use?

   • AStore a SHA-256 hash of each file in a database.
   • BEncrypt each file with AES and store the key in the same database.
   • CStore the file size and last modified timestamp.
   • DStore an HMAC-SHA256 of each file using a secret key held in a hardware security module (HSM).
   Reveal Solution Discussion Select an answer first
6. 40foundation · easy

   What is the purpose of certificate revocation?

   • ATo extend the validity period of a certificate
   • BTo invalidate a certificate before its expiration date
   • CTo change the public key in a certificate
   • DTo back up the certificate's private key
   Reveal Solution Discussion Select an answer first