Asymmetric Cryptography and Key Algorithms BDC Practice Questions (Page 8)

Questions 36–40

1. 36expert · hard

   A company runs a permissioned blockchain where each node has a key pair. The security team requires that if a node is compromised, its key can be invalidated without affecting other nodes. Which approach should be implemented?

   • ADelete the compromised node from the network.
   • BShare the compromised private key with all other nodes.
   • CRegenerate the compromised node's key pair and update its address.
   • DUse a certificate authority (CA) to issue and revoke node certificates.
   Reveal Solution Discussion Select an answer first
2. 37expert · hard

   A security auditor is reviewing a blockchain system that uses asymmetric cryptography. The auditor finds that the system uses the same key pair for both encrypting messages and signing transactions. What is the primary security concern with this practice?

   • AIt allows anyone to decrypt messages encrypted with the public key.
   • BIt is not a security concern; using the same key pair is a best practice.
   • CIt makes the key pair weaker because the key size must be larger.
   • DUsing the same key pair for encryption and signing can allow an attacker to trick the key holder into signing a message that is actually an encrypted message, potentially revealing the private key.
   Reveal Solution Discussion Select an answer first
4. 38foundation · easy

   How does a verifier check the authenticity and integrity of a digitally signed message?

   • ABy sending the signature to a trusted third party for manual inspection.
   • BBy decrypting the signature with the signer's private key and comparing it to the message hash.
   • CBy using the signer's public key to verify the signature against the message hash.
   • DBy comparing the signature to a pre-shared secret key.
   Reveal Solution Discussion Select an answer first
5. 39application · medium

   A blockchain platform needs to select an asymmetric algorithm for signing transactions. The platform runs on low-power IoT devices with limited CPU and memory, and the signing operation must be fast and produce short signatures to minimize transaction size. Which algorithm is the most appropriate choice?

   • AElliptic Curve Cryptography (ECC) with a 256-bit curve
   • BSymmetric AES-256 with a shared key
   • CDiffie-Hellman key exchange
   • DRSA with a 2048-bit key
   Reveal Solution Discussion Select an answer first
6. 40foundation · easy

   Which of the following is a primary advantage of Elliptic Curve Cryptography (ECC) over RSA for the same level of security?

   • AECC is a symmetric algorithm, making it simpler to implement.
   • BECC is faster for encryption but slower for decryption.
   • CECC uses smaller key sizes, resulting in faster computations and reduced storage requirements.
   • DECC requires larger key sizes to achieve equivalent security.
   Reveal Solution Discussion Select an answer first