SSCP Cryptography — 20 Questions

Question 1

A security administrator is configuring a web server to use TLS. They want to optimize performance while maintaining strong security. Which cipher suite should they prioritize?

Accepted Answer

TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384. TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uses Elliptic Curve Diffie-Hellman Ephemeral (ECDHE) for perfect forward secrecy, ECDSA for efficient authentication, AES-256 in GCM mode for authenticated encryption, and SHA-384 for integrity. This combination provides the strongest security with modern, optimized algorithms, making it the best choice for performance and security on a TLS web server.

Answer

TLS_DHE_RSA_WITH_AES_128_CBC_SHA

Answer

TLS_RSA_WITH_AES_128_CBC_SHA256

Answer

TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256

Question 2

A security team is evaluating hashing algorithms for use in a new system. Which of the following are considered currently secure for general use? (Select TWO)

Accepted Answer

SHA-3. SHA-3 (Option C) is correct because it is the latest NIST-standardized hash function family (FIPS 202), based on the Keccak sponge construction, and remains cryptographically secure with no practical collision or preimage attacks. SHA-256 (Option D) is also correct because it is part of the SHA-2 family (FIPS 180-4) and is widely trusted and recommended for general-purpose hashing, with no known practical attacks against it. SHA-1 (Option A) is not secure for general use because practical collision attacks (e.g., SHAttered) have been demonstrated, making it unsuitable for digital signatures or integrity protection. MD5 (Option B) is broken, with trivial collision generation, so it must not be used for security purposes. HMAC-SHA256 (Option E) is a message authentication code (keyed hash) rather than a general-purpose hashing algorithm, so it does not fit the question's scope of selecting secure hashing algorithms for general use.

Answer

SHA-1

Answer

MD5

Answer

HMAC-SHA256

Question 3

An organization is moving away from legacy encryption and wants to avoid stream ciphers due to known vulnerabilities. Which of the following algorithms should be avoided because it is a stream cipher with known weaknesses like the BEAST attack?

Accepted Answer

RC4. RC4 is a stream cipher with known weaknesses, such as biases in its output stream that can lead to plaintext recovery attacks. Although the BEAST attack actually exploits CBC mode in TLS 1.0, RC4 was often used as a workaround; however, RC4 itself has inherent vulnerabilities, making it unsuitable for secure encryption. Since the organization wants to avoid stream ciphers due to such vulnerabilities, RC4 should be avoided.

Answer

3DES

Answer

AES-GCM

Answer

ChaCha20

Question 4

An organization is implementing a digital signature solution to ensure non-repudiation and integrity of documents. Which three of the following are true regarding digital signatures?

Accepted Answer

The receiver verifies the signature using the sender's public key.. Option B is correct because signature verification always uses the sender's public key: the receiver decrypts the signature value with that public key and compares the recovered hash to a freshly computed hash of the message. Option D is correct because non-repudiation rests on the sender being the sole holder of the private key, so a signature that validates under the sender's public key could only have been produced by that sender, binding them to the document. Option E is correct because signing operates on a message digest, not the whole document: the sender hashes the message and then encrypts (signs) that hash with their private key, which is efficient and preserves integrity. Option A is wrong because the private key is never shared with the receiver; verification uses the public key. Option C is wrong because encrypting the entire document with the sender's public key would not create a signature and would be nonsensical, since the sender's public key is not used for signing and the sender does not hold the matching private key for decryption by others.

Answer

The receiver uses the sender's private key to verify the signature.

Answer

The sender encrypts the entire document with their public key to create a signature.

Question 5

A security engineer is designing a system that must securely store encryption keys used for data-at-rest encryption. The keys must be protected against extraction even if the host is compromised, and the solution must support hardware-based key generation and storage. Which technology should the engineer implement?

Accepted Answer

Hardware Security Module (HSM). An HSM provides hardware-based key generation and secure storage with tamper-resistant features, ensuring keys cannot be extracted even if the host is compromised. A TPM is limited to a single host, software key stores lack hardware protection, and KMIP is a protocol rather than a hardware module. The HSM best meets the requirements.

Answer

Software-based key store with AES-256 encryption

Answer

Key Management Interoperability Protocol (KMIP) server

Answer

Trusted Platform Module (TPM)

Question 6

A financial institution wants to ensure that a large file transferred between two branches has not been altered in transit. The security team decides to use a cryptographic hash function. Which of the following properties of the hash function is most critical for detecting accidental or malicious modifications?

Accepted Answer

Collision resistance. Collision resistance is the most critical property because it prevents an attacker from finding any two different files that produce the same hash. If collisions are feasible, a modified file could be substituted without changing the hash, defeating integrity checks. Preimage and second preimage resistance are related but weaker, and HMAC adds authentication but depends on collision resistance.

Answer

Keyed hash (HMAC) construction

Answer

Preimage resistance

Answer

Second preimage resistance

Question 7

A security team is deploying a VPN that uses IPsec in tunnel mode. The team must ensure the VPN provides confidentiality, integrity, and authentication of data in transit. Which two of the following components should be used to meet these requirements? (Choose two.)

Accepted Answer

IKE (Internet Key Exchange). ESP and IKE are essential for an IPsec VPN. ESP provides confidentiality, integrity, and authentication of the data, while IKE negotiates and manages the security associations and keys. AH lacks confidentiality, SSL/TLS is not part of IPsec, and GRE provides encapsulation without security. Together, ESP and IKE meet all requirements.

Answer

GRE (Generic Routing Encapsulation)

Answer

AH (Authentication Header)

Answer

SSL/TLS

Question 8

A healthcare organization must ensure that stored patient records remain confidential even if an attacker gains physical access to the storage array and removes the disks. The security team wants to use full-disk encryption with a hardware module that protects the encryption keys and performs cryptographic operations independently of the host CPU. Which technology BEST meets these requirements?

Accepted Answer

Self-Encrypting Drive (SED) with Opal support. A self-encrypting drive performs AES encryption within the drive controller, so all data at rest is ciphertext and the media encryption key is bound to the drive. This protects against physical removal of disks without burdening the host CPU, unlike TPM sealing, HSM-assisted column encryption, or file-level EFS, which do not encrypt the entire volume or do not operate independently of the host.

Answer

Trusted Platform Module (TPM)

Answer

Hardware Security Module (HSM) configured for database column encryption

Answer

File-level encryption using EFS with a recovery agent

Question 9

A security administrator is implementing cryptographic controls for a new application that stores sensitive customer data. The administrator must ensure that data at rest is encrypted and that any tampering can be detected. Which two of the following should the administrator implement to meet these requirements? (Choose two.)

Accepted Answer

Use AES-256 in GCM mode for encryption. Using AES-256-GCM provides authenticated encryption, ensuring both confidentiality and integrity in one step. Alternatively, encrypting with a secure mode and then applying HMAC-SHA256 over the ciphertext also meets the requirements. RSA is unsuitable for bulk data, Base64 is not encryption, and an unkeyed hash of plaintext lacks confidentiality and authentication.

Answer

Apply Base64 encoding to the stored data

Answer

Use RSA-2048 to encrypt the data directly

Answer

Generate a SHA-256 hash of the plaintext and store it alongside

Question 10

A security analyst is recommending a symmetric encryption algorithm for a new application that requires both confidentiality and authentication. Which algorithm and mode combination should they select?

Accepted Answer

AES-GCM. AES-GCM (Galois/Counter Mode) is a symmetric encryption algorithm that provides both confidentiality and authentication in a single, efficient operation. It combines AES encryption in counter mode with a Galois field-based message authentication code (GMAC), making it ideal for applications requiring both security properties.

Answer

3DES-CBC

Answer

AES-ECB

Answer

RC4

Question 11

An organization is implementing a digital signature solution to ensure non-repudiation of documents. Which combination of keys is used during the signing process?

Accepted Answer

Sender's private key to sign, sender's public key to verify. Digital signatures use asymmetric cryptography where the sender creates a signature with their private key, and the recipient verifies it with the sender's public key. This ensures non-repudiation because only the sender possesses their private key, so they cannot deny having signed the document. The process typically involves hashing the document and encrypting the hash with the sender's private key.

Answer

Recipient's public key to sign, recipient's private key to verify

Answer

Sender's public key to sign, recipient's private key to verify

Answer

A shared symmetric key for both signing and verification

Question 12

A company is deploying a VPN using IPsec. They want to ensure that even if the private key of the server is compromised, past session keys cannot be derived. Which key exchange method should they use?

Accepted Answer

Ephemeral Diffie-Hellman (DHE or ECDHE). Ephemeral Diffie-Hellman (DHE or ECDHE) provides perfect forward secrecy (PFS) because it generates a unique, temporary session key for each session using ephemeral key pairs. Even if the server's long-term private key is compromised, past session keys cannot be derived because they were created from ephemeral keys that are discarded after each session. This ensures that historical encrypted traffic remains secure.

Answer

Pre-shared key (PSK)

Answer

RSA key exchange

Answer

Diffie-Hellman with static keys

Question 13

Which of the following hash algorithms is considered cryptographically broken and should be avoided due to collision attacks?

Accepted Answer

MD5. MD5 is considered cryptographically broken because collision attacks can easily generate two different inputs with the same hash value. This undermines its use for digital signatures, certificates, and integrity checks. SHA-3, SHA-256, and HMAC-SHA256 are still considered secure for cryptographic purposes.

Answer

SHA-3

Answer

SHA-256

Answer

HMAC-SHA256

Question 14

An organization uses a PKI with a root CA that issues certificates to intermediate CAs, which then issue end-entity certificates. A client receives an end-entity certificate signed by an intermediate CA. During validation, which certificates are required to build the chain of trust?

Accepted Answer

End-entity certificate, intermediate CA certificate, and root CA certificate. In a PKI hierarchy, the chain of trust requires each certificate in the path to be validated up to a trusted root. The client must have the end-entity certificate, the intermediate CA certificate (to verify the end-entity's signature), and the root CA certificate (to verify the intermediate CA's signature). Without the intermediate CA certificate, the client cannot cryptographically link the end-entity to the root, breaking the chain.

Answer

Only the root CA certificate

Answer

Only the end-entity certificate and the root CA certificate

Answer

Only the end-entity certificate and the intermediate CA certificate

Question 15

A security engineer needs to choose an asymmetric algorithm for a system with limited computational resources, such as an IoT device. The algorithm must provide equivalent security to RSA 2048-bit while using smaller key sizes. Which algorithm should they choose?

Accepted Answer

Elliptic Curve Cryptography (ECC) with 256-bit keys. Elliptic Curve Cryptography (ECC) with 256-bit keys provides equivalent security to RSA 2048-bit because the elliptic curve discrete logarithm problem is significantly harder to solve than the integer factorization problem for the same key length. This allows ECC to achieve strong security with much smaller key sizes, making it ideal for resource-constrained IoT devices where memory, power, and processing are limited.

Answer

RSA with 2048-bit keys

Answer

Diffie-Hellman with 2048-bit keys

Answer

3DES with 168-bit keys

Question 16

A security auditor reviews a system that uses HMAC-SHA256 for message authentication. Which property does HMAC provide that a simple hash of the message does not?

Accepted Answer

Integrity and authentication using a shared secret. HMAC-SHA256 uses a shared secret key combined with the message before hashing, which provides both integrity (detecting tampering) and authentication (verifying the sender knows the secret). A simple hash of the message alone offers integrity but no authentication, because anyone can compute the same hash without a secret. Thus, HMAC adds authentication via the shared secret, making option C correct.

Answer

Confidentiality

Answer

Non-repudiation

Answer

Forward secrecy

Question 17

Which of the following is a secure protocol for remote administration of a server, replacing insecure protocols like Telnet?

Accepted Answer

SSH. SSH (Secure Shell) is the correct answer because it provides encrypted remote administration capabilities, replacing insecure protocols like Telnet that transmit data in plaintext. SSH uses public-key cryptography for authentication and symmetric encryption (e.g., AES, ChaCha20) for session confidentiality, protecting against eavesdropping and man-in-the-middle attacks.

Answer

FTP

Answer

HTTP

Answer

Telnet

Question 18

A company wants to implement a key management system. They need to generate cryptographic keys that are unpredictable. Which source of randomness should be used?

Accepted Answer

Hardware random number generator (HRNG). A hardware random number generator (HRNG) is the correct choice because it derives randomness from physical processes (e.g., thermal noise, quantum effects) that are inherently unpredictable and non-deterministic. Cryptographic key generation requires true entropy to resist brute-force and prediction attacks, which software-based deterministic methods cannot guarantee.

Answer

Random numbers from a website

Answer

Linear congruential generator (LCG)

Answer

Pseudorandom number generator (PRNG) seeded with current timestamp

Question 19

A certificate authority (CA) issues a certificate with the extended key usage (EKU) extension specifying 'serverAuth'. Which of the following is this certificate allowed to do?

Accepted Answer

Authenticate a TLS server. The Extended Key Usage (EKU) extension specifies the intended purpose of a certificate. The 'serverAuth' OID (1.3.6.1.5.5.7.3.1) explicitly permits the certificate to be used for authenticating a TLS server during the SSL/TLS handshake, such as in HTTPS. This is defined in RFC 5280 and is enforced by TLS clients to ensure the certificate is used only for its designated purpose.

Answer

Encrypt email

Answer

Sign code

Answer

Issue subordinate CA certificates

Question 20

Which of the following is a method to check the revocation status of a digital certificate in real-time without the client downloading a full list?

Accepted Answer

Online Certificate Status Protocol (OCSP). OCSP (Online Certificate Status Protocol) lets a client query a responder in real time for the revocation status of a specific certificate, returning 'good,' 'revoked,' or 'unknown' without downloading the entire CRL. It is defined in RFC 6960 and is the standard real-time alternative to CRLs. This matches the requirement exactly.

Answer

Certificate Revocation List (CRL)

Answer

Self-signed certificate validation

Answer

Certificate Transparency (CT)