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The ECES exam has 50 questions and runs 2 hours.
These 10 free ECES questions are organized by exam domain, so you can see how each part of the EC-Council Certified Encryption Specialist blueprint is tested. Reveal the answer and explanation under each question.
A historical substitution scheme assigns E the symbols 18, 42, or 76; T the symbols 25 or 63; and Q the symbol 09. The sender may choose any symbol assigned to a letter, but each ciphertext symbol identifies only one plaintext letter. More alternatives are assigned to common letters to flatten ciphertext frequencies. This construction is an example of:
Correct answer: D - Homophonic substitution
In a recovery test, an engineer flips one bit in the third ciphertext block of an unauthenticated AES-encrypted backup. After decryption, the third plaintext block is garbled, the fourth has exactly the corresponding bit flipped, and later blocks are unchanged. Block boundaries have not shifted. Which mode produces this error-propagation pattern?
Correct answer: C - Cipher Block Chaining (CBC)
A password-storage review finds two weaknesses: accounts with the same password have identical stored verifiers, and each offline guess requires only one fast SHA-256 computation. The replacement must address both findings. Which design meets that requirement?
Correct answer: B - Use PBKDF2-HMAC-SHA-256 with per-account random salts and a calibrated work factor.
A reviewer flags a protocol because each AES-CBC message carries its IV in cleartext. Every IV is freshly generated and unpredictable. An HMAC under a separate secret key covers the IV and ciphertext, and the receiver verifies it before decrypting. How should the reported IV exposure be handled?
Correct answer: D - Retain the IV handling; a CBC IV need not be secret.
An encoder must store a 37-byte binary record using AES-256-CBC with PKCS#7 padding. Its output consists of a 16-byte IV, the ciphertext, and a 32-byte HMAC, with no other fields or encoding. The IV and HMAC are not encrypted. What is the minimum output-buffer size?
Correct answer: A - 96 bytes
A message format permits one RSA-OAEP ciphertext, using a trusted 2048-bit recipient public key and SHA-256. A sender must deliver an entire 240-byte record confidentially without changing those RSA-OAEP parameters. OAEP permits at most k - 2hLen - 2 input bytes, where k is the modulus length in bytes and hLen is the hash-output length in bytes. Which plan fits?
Correct answer: C - Encrypt a fresh 32-byte AES key with RSA-OAEP; protect the record with AES-GCM.
An attacker recorded two complete TLS connections that used the same server RSA certificate: one used TLS 1.2 RSA key transport, and the other used TLS 1.3 certificate-authenticated ECDHE. Both connections ended before the server's RSA private key was stolen. Ephemeral private values and traffic secrets were erased, and neither endpoint was otherwise compromised. Which recorded traffic becomes recoverable from this key exposure alone?
Correct answer: C - Only the connection that used RSA key transport.
After a web-server replacement, fresh clients report that they cannot build a certificate chain. They already trust the correct root CA. The server sends only its leaf certificate; providing the issuing intermediate certificate during a diagnostic test makes every validation check succeed. There is no evidence of private-key exposure. What is the appropriate repair without changing client trust anchors?
Correct answer: A - Configure the server to send its leaf certificate and the issuing intermediate.
Two branch gateways must protect traffic across the Internet. Observers may see the gateways' public addresses, but must not see either the original host IP headers or the application data. The gateways will use no additional encapsulation layer beyond the selected VPN protocol. Select the profile that satisfies these requirements.
Correct answer: B - ESP in tunnel mode with authenticated encryption
During an authorized assessment, an auditor can submit arbitrary plaintexts to a service that encrypts them under one fixed, unknown key. The auditor chooses later inputs after examining earlier ciphertexts. There is no decryption interface and no ability to alter the key. How is this access classified?
Correct answer: A - Adaptive chosen-plaintext access
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