Modern Cryptographic Attacks ECES Practice Questions (Page 2)

Questions 6–10

1. 6foundation · easy

   Which of the following is a common mitigation against timing side-channel attacks?

   • AAdding random delays to all cryptographic operations.
   • BUsing a stronger encryption algorithm, such as AES-256 instead of AES-128.
   • CUsing a constant-time implementation for cryptographic operations.
   • DEncrypting all network traffic with TLS.
   Reveal Solution Discussion Select an answer first
2. 7application · medium

   A developer is using a cryptographic library to generate RSA keys. The library's random number generator is later found to be predictable because it was seeded with the current timestamp. Which attack does this enable, and what is the correct remediation?

   • ATiming attack; implement constant-time RSA
   • BPadding oracle attack; use OAEP padding
   • CReplay attack; add a nonce to the encryption
   • DKey recovery attack; use a cryptographically secure random number generator (CSPRNG) with a high-entropy seed
   Reveal Solution Discussion Select an answer first
4. 8application · medium

   A security architect is evaluating a new encryption system for a healthcare application. The system uses AES-256 in CBC mode with a static IV and no message authentication. Which combination of attacks is the system most vulnerable to, and what is the best overall fix?

   • ATiming side-channel; use constant-time decryption
   • BReplay attacks; add a timestamp to the ciphertext
   • CPadding oracle attacks; use a different padding scheme
   • DChosen-plaintext attacks and data tampering; use AES-GCM with a unique IV per encryption
   Reveal Solution Discussion Select an answer first
5. 9foundation · easy

   Which of the following is a best-practice countermeasure to protect against known cryptographic attacks?

   • ARelying on the secrecy of the cryptographic algorithm to prevent attacks.
   • BKeeping cryptographic libraries up to date with the latest security patches.
   • CUsing the same key for encryption and authentication to reduce complexity.
   • DDisabling all cryptographic protocols that are not absolutely necessary.
   Reveal Solution Discussion Select an answer first
6. 10application · medium

   A cloud service runs AES encryption on shared physical servers. A researcher demonstrates that by carefully monitoring the CPU cache, they can infer secret key material used by another tenant's process. Which side-channel attack is this, and what is a practical mitigation in a shared environment?

   • APower analysis attack; use a UPS with power filtering
   • BTiming attack; add random delays to encryption
   • CElectromagnetic attack; use shielded enclosures
   • DCache-timing attack; use dedicated hardware or isolate tenants with virtual machine isolation and cache partitioning
   Reveal Solution Discussion Select an answer first