10 free EC-Council 212-81v3 ECES practice questions with the correct answer and a full explanation for each, taken from the CertStash pack of 64 questions. Work through them, then open each answer to check your reasoning.
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Question 1
3DES can best be classified as which one of the following?
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Correct answer: C. Symmetric algorithm
3DES (Triple Data Encryption Standard) is a symmetric encryption algorithm that applies the DES cipher three times to each data block. Symmetric algorithms use the same key for both encryption and decryption, making 3DES a symmetric cipher rather than any other cryptographic primitive.
Why the other options are wrong
- A. Hashing algorithms produce fixed-size digests and are not used for encryption; 3DES is a cipher for reversible encryption.
- B. Digital signatures use asymmetric cryptography to provide authentication and no-epudiation; 3DES is an encryption algorithm.
- D. Asymmetric algorithms use different keys for encryption and decryption; 3DES uses the same key for both operations.
Question 2
You have been tasked with selecting a digital certificate standard for your company to use.
Which one of the following is an international standard for the format and information contained in a digital certificate?
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Correct answer: D. X.509
X.509 is the internationally recognized standard (ITU-T) that defines the format, structure, and information contained within digital certificates. It specifies how certificate data is organized and what fields must be present, making it the standard for certificate format selection.
Why the other options are wrong
- A. CA refers to a Certificate Authority, which is an entity that issues certificates, not a certificate format standard.
- B. CRL is a Certificate Revocation List used to identify revoked certificates, not a format standard for certificates themselves.
- C. RFC 2298 relates to Message Disposition Notifications, not digital certificate format standards.
Question 3
What is the basis for the difficulty in breaking RSA?
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Correct answer: A. Factoring numbers
RSA's security is based on the computational difficulty of factoring large composite numbers into their prime factors. The public key contains a modulus that is the product of two large primes, and breaking RSA requires factoring this modulus to recover the private key.
Why the other options are wrong
- B. Hashing is not the basis of RSA security; RSA is a public-key encryption algorithm, not a hashing function.
- C. Elliptic curve mathematics is the basis for elliptic curve cryptography (ECC), not RSA.
- D. The birthday paradox relates to hash collision probability, not RSA's security foundation.
Question 4
How does Kerberos generate the first secret key in the authentication process?
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Correct answer: A. By creating a hash of the user password
Kerberos generates the initial secret key by creating a cryptographic hash of the user's password. This derived key serves as the basis for the authentication process and is used to decrypt the ticket-granting ticket (TGT) received from the KDC.
Why the other options are wrong
- B. Kerberos does not generate random AES keys as the first step; it derives a key from the password.
- C. Kerberos is a symmetric key system and does not use the user's public key for generating the initial secret.
- D. While Kerberos uses salt in password-based key derivation, the process is fundamentally a hash of the password, not a hash of user ID, network ID, and salt combined.
Question 5
The mode makes a block cipher into a synchronous stream cipher. It generates keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext.
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Correct answer: B. Output feedback (OFB)
Output Feedback (OFB) mode converts a block cipher into a synchronous stream cipher by generating keystream blocks independently of the plaintext. These keystream blocks are then XORed with plaintext blocks to produce ciphertext, making it a true stream cipher mode.
Why the other options are wrong
- A. ECB (Electronic Codebook) is not a stream cipher mode; it encrypts each block independently without generating keystream.
- C. CFB (Cipher Feedback) is a stream cipher mode but it generates keystream that depends on previous ciphertext, making it asynchronous rather than synchronous.
- D. CBC (Cipher Block Chaining) is a block cipher mode that chains blocks together and does not operate as a stream cipher.
Question 6
Ferris has been assigned the task of selecting security for his company’s wireless network. It is important that he pick the strongest form of wireless security.
Which one of the following is the strongest wireless security?
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Correct answer: C. WPA2
WPA2 (Wi-Fi Protected Access 2) is the strongest wireless security standard among the options, using AES encryption with robust authentication mechanisms. It supersedes both WEP and WPA, providing significantly stronger security against cryptographic attacks and unauthorized access.
Why the other options are wrong
- A. WEP (Wired Equivalent Privacy) is an outdated security standard with known vulnerabilities that make it cryptographically breakable.
- B. TKIP (Temporal Key Integrity Protocol) was an improvement over WEP but is weaker than WPA2 and has known weaknesses.
- D. WPA (Wi-Fi Protected Access) is stronger than WEP and TKIP but was replaced by the more secure WPA2 standard.
Question 7
Tom is explaining historical cryptography to a class of security students.
Which of the following ciphers is a subset of the Vigenère cipher?
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Correct answer: B. Caesar
The Caesar cipher is a subset of the Vigenère cipher. The Vigenère cipher is a polyalphabetic substitution cipher that uses a key, and the Caesar cipher is a special case where the Vigenère key has a length of one (single shift value), making it a monoalphabetic substitution cipher.
Why the other options are wrong
- A. The Scytale is a transposition cipher using a physical device, not a substitution cipher related to Vigenère.
- C. Blowfish is a modern symmetric block cipher unrelated to historical substitution ciphers like Vigenère.
- D. Atbash is an ancient substitution cipher that does not relate to the Vigenère cipher framework.
Question 8
What is a variation of DES that uses a technique called Key Whitening?
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Correct answer: C. DESX
DESX (DES with eXtended key) is a variation of DES that incorporates key whitening, a technique that XORs the plaintext with part of the key before encryption and XORs the ciphertext with another key part after encryption. This enhances DES security against certain attacks.
Why the other options are wrong
- A. AES (Advanced Encryption Standard) is a completely different cipher architecture and does not use key whitening as an extension of DES.
- B. 3DES (Triple DES) applies DES multiple times but does not use the key whitening technique.
- D. Blowfish is an independent block cipher design that does not involve key whitening as a DES variant.
Question 9
While many companies are working on quantum computing, what is the current biggest challenge?
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Correct answer: B. Decoherence
Decoherence is the primary technical barrier to practical quantum computing. Quantum bits lose their quantum properties when they interact with their environment, causing errors that degrade computational results. While processing speed, funding, and power needs are important considerations, decoherence remains the fundamental physics problem that must be solved before quantum computers can achieve reliable, scalable operation.
Why the other options are wrong
- A. Modern quantum computers already perform certain calculations faster than classical computers for specific problems; speed advantage is achievable despite other limitations.
- C. Funding, though significant, is a resource issue rather than the core technical obstacle preventing quantum computing advancement.
- D. Power consumption is manageable with current technology and is not the primary scientific challenge limiting quantum computing development.
Question 10
Which of the following techniques is used (other than brute force) to attempt to derive a key?
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Correct answer: D. Cryptanalysis
Cryptanalysis encompasses the study and practice of breaking cryptographic systems through mathematical analysis and techniques, distinct from brute force attacks. It includes methods such as frequency analysis, differential cryptanalysis, and linear cryptanalysis. Cryptanalysis is the formal discipline of discovering weaknesses in ciphers and deriving keys without exhaustively trying all possibilities.
Why the other options are wrong
- A. Password cracking is a technique for obtaining passwords through various means, not a method for deriving cryptographic keys from ciphertext.
- B. Cryptography is the practice of creating ciphers and secure systems, not attacking them to derive keys.
- C. Hacking is too broad and general; it does not specifically refer to key derivation techniques in cryptography.
That was 10 of 64.
The full EC-Council 212-81v3 ECES pack has all 64 questions, each with the answer, the explanation and why the other options are wrong, plus a questions-only copy for timed runs. US$39, paid once, with free monthly updates and a pass-or-your-money-back guarantee.