Hashing, Digital Signatures, and Digital Certificates CASENET Practice Questions (Page 5)

Questions 21–25

1. 21expert · hard

   A .NET application must support digital signatures for a large number of IoT devices. The devices have limited CPU and memory. The signature must provide non-repudiation and be efficient to verify. Which algorithm should the developer choose?

   • AECDSA with P-256 curve
   • BHMAC-SHA256 with a shared secret
   • CDSA with 1024-bit keys
   • DRSA with 2048-bit keys
   Reveal Solution Discussion Select an answer first
2. 22foundation · easy

   In a public key infrastructure (PKI), what is a certificate chain?

   • AA sequence of certificates that links a certificate to a trusted root CA
   • BA group of certificates that share the same public key
   • CA set of certificates that have expired
   • DA list of revoked certificates
   Reveal Solution Discussion Select an answer first
4. 23foundation · easy

   Which hashing algorithm is considered cryptographically broken and should not be used for security purposes?

   • ASHA-3
   • BSHA-1
   • CSHA-256
   • DSHA-512
   Reveal Solution Discussion Select an answer first
5. 24application · medium

   A .NET developer needs to sign a small message (under 100 bytes) using ECDSA and verify it in a separate process. Which .NET API sequence correctly performs signing and verification?

   • AUse RSA.Create() to generate a key, call SignData() with the message, then use VerifyData() with the same key.
   • BUse ECDsa.Create() to generate a key, call SignData() with the message and a hash algorithm, then use VerifyData() with the public key.
   • CUse HMACSHA256.Create() to generate a key, call ComputeHash() on the message, then compare the hash.
   • DUse SHA256.Create() to hash the message, then encrypt the hash with AES using a shared key.
   Reveal Solution Discussion Select an answer first
6. 25foundation · easy

   Which of the following is a characteristic of the RSA digital signature algorithm?

   • AIts security relies on the difficulty of factoring large composite numbers.
   • BIt uses the same key for signing and verification.
   • CIt is based on the difficulty of the discrete logarithm problem.
   • DIt is a symmetric-key algorithm.
   Reveal Solution Discussion Select an answer first