Modern Cryptographic Attacks ECES Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   A security researcher is analyzing a hardware token that performs AES encryption. The researcher notices that the token's power consumption varies slightly depending on the secret key bits being processed. Which side-channel attack is this, and what is a common mitigation?

   • APower analysis attack; use masking or constant-power operations
   • BElectromagnetic attack; shield the device with a Faraday cage
   • CTiming attack; add random delays to the encryption process
   • DCache-timing attack; flush the cache before each operation
   Reveal Solution Discussion Select an answer first
2. 32foundation · easy

   When evaluating the real-world security of a cryptographic system, which of the following is the most important factor to consider?

   • AThe overall system, including implementation, protocol usage, and operational practices.
   • BThe secrecy of the algorithm's design.
   • CThe length of the encryption key used.
   • DThe mathematical strength of the encryption algorithm alone.
   Reveal Solution Discussion Select an answer first
4. 33application · medium

   A legacy VPN appliance supports both IKEv1 and IKEv2, and a security scan shows that it accepts IKEv1 with weak Diffie-Hellman groups. You need to eliminate the risk of a downgrade attack. What should you do?

   • AUse a pre-shared key instead of certificates for IKEv1 authentication.
   • BKeep IKEv1 enabled but increase the Diffie-Hellman group to 14 for all connections.
   • CDisable IKEv1 and configure the appliance to accept only IKEv2 with strong Diffie-Hellman groups.
   • DConfigure the appliance to prefer IKEv2 but allow IKEv1 as a fallback.
   Reveal Solution Discussion Select an answer first
5. 34application · medium

   A hardware security module (HSM) is used to protect cryptographic keys. A researcher places a probe near the HSM and captures electromagnetic emissions that correlate with the secret key operations. Which side-channel attack is this, and what is a common countermeasure?

   • APower analysis attack; use a battery backup
   • BTiming attack; add random delays to operations
   • CElectromagnetic (EM) attack; use electromagnetic shielding or reduce emissions with differential logic
   • DCache-timing attack; disable caching in the HSM
   Reveal Solution Discussion Select an answer first
6. 35application · medium

   A security engineer is investigating a smart-card authentication system used for building access. The engineer notices that the card reader consistently takes measurably longer to reject a PIN when the first digit is correct. Which type of attack is the engineer observing, and what is the most direct mitigation?

   • APower analysis attack; add noise to the power supply
   • BProtocol rollback attack; enforce the latest authentication protocol version
   • CCache-timing attack; flush the CPU cache after each attempt
   • DTiming side-channel attack; implement constant-time PIN comparison
   Reveal Solution Discussion Select an answer first