SSCP Cryptography — 20 Questions

Question 1

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 (C) is the latest member of the Secure Hash Algorithm family, standardized by NIST in FIPS 202. It is based on the Keccak sponge construction and is not susceptible to the collision attacks that weaken SHA-1 or the length-extension vulnerabilities of SHA-2, making it currently secure for general use.

Answer

SHA-1

Answer

MD5

Answer

HMAC-SHA256

Question 2

An analyst is comparing symmetric and asymmetric encryption. Which statement accurately describes a typical use case?

Accepted Answer

Asymmetric encryption is used to securely exchange a symmetric key.. Asymmetric encryption (e.g., RSA, ECDH) is computationally expensive and slow, making it unsuitable for bulk data encryption. Instead, it is commonly used to securely exchange a symmetric session key (e.g., an AES key) over an insecure channel. Once both parties have the symmetric key, they can switch to symmetric encryption (e.g., AES-GCM) for efficient bulk data encryption. This hybrid approach combines the secure key distribution of asymmetric encryption with the speed of symmetric encryption.

Answer

Symmetric encryption is used for key exchange over insecure channels.

Answer

Symmetric encryption is used to sign documents to provide non-repudiation.

Answer

Asymmetric encryption is used for bulk data encryption because it is faster.

Question 3

Which of the following is a secure alternative to RC4 for stream ciphers?

Accepted Answer

ChaCha20. ChaCha20 is a modern, high-speed stream cipher designed by Daniel J. Bernstein as a secure alternative to RC4, which has known vulnerabilities such as biases in its keystream and susceptibility to attacks like the Fluhrer-Mantin-Shamir attack. ChaCha20 is standardized in RFC 8439 and is widely used in TLS 1.3 and SSH, offering strong security and performance without the weaknesses of RC4.

Answer

MD5

Answer

AES in ECB mode

Answer

3DES

Question 4

A security engineer is designing a system that requires non-repudiation of data origin. Which cryptographic technique should be used?

Accepted Answer

Digital signature using RSA or ECDSA. Digital signatures using RSA or ECDSA provide non-repudiation of data origin because they bind the signer's identity to the data through a private key that only the signer possesses. The recipient can verify the signature with the corresponding public key, and the signer cannot later deny having signed the data, as the private key is uniquely under their control. This meets the legal and technical requirement for non-repudiation, unlike symmetric or hash-only methods.

Answer

Keyed hash (HMAC)

Answer

Hash function only

Answer

Symmetric encryption with a shared key

Question 5

An organization is planning to implement ECC for digital signatures. Which key size provides a security level equivalent to a 3072-bit RSA key?

Accepted Answer

256-bit ECC. The National Institute of Standards and Technology (NIST) recommends that a 256-bit elliptic curve (e.g., P-256) provides a security strength of 128 bits, which is equivalent to a 3072-bit RSA key. This equivalence is based on the computational difficulty of the discrete logarithm problem in elliptic curve groups versus integer factorization, where ECC requires significantly smaller key sizes for the same security level.

Answer

192-bit ECC

Answer

1024-bit ECC

Answer

384-bit ECC

Question 6

Which protocol is used to provide secure remote shell access and replace Telnet?

Accepted Answer

SSH. SSH (Secure Shell) is the correct answer because it provides encrypted remote shell access and command execution, replacing the insecure Telnet protocol which transmits data in cleartext. SSH uses public-key cryptography for authentication and symmetric encryption (e.g., AES, ChaCha20) for session confidentiality, as defined in RFC 4251.

Answer

SFTP

Answer

IPsec

Answer

HTTPS

Question 7

In a PKI, what is the role of the root Certificate Authority (CA)?

Accepted Answer

To be the trust anchor for the entire PKI hierarchy. The root Certificate Authority (CA) is the trust anchor in a Public Key Infrastructure (PKI) hierarchy. Its self-signed root certificate is the ultimate trust point from which all subordinate CA certificates and end-entity certificates derive their trust. Without a trusted root, the entire chain of trust collapses, as no certificate can be validated back to a trusted source.

Answer

To issue certificates directly to end users

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To generate private keys for all users

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To revoke certificates and publish CRLs

Question 8

A security administrator is evaluating encryption protocols for email communication. Which of the following protocols can secure email in transit? (Select TWO)

Accepted Answer

IMAPS. IMAPS (Internet Message Access Protocol over SSL/TLS) encrypts email retrieval by wrapping IMAP traffic in TLS, typically on port 993. This ensures that email messages and credentials are protected from eavesdropping while in transit between the client and the mail server.

Answer

HTTPS

Answer

SSH

Answer

SFTP

Question 9

Which of the following are considered secure cryptographic practices for key management? (Select THREE)

Accepted Answer

Implementing regular key rotation. Regular key rotation limits the amount of data encrypted with a single key, reducing the impact of a key compromise and aligning with cryptographic best practices such as NIST SP 800-57. Rotating keys ensures that even if a key is exposed, only data encrypted after the last rotation is vulnerable, and it helps enforce cryptographic hygiene by retiring keys before they become weak due to cryptanalytic advances.

Answer

Storing keys in plaintext configuration files

Answer

Sharing keys over email for convenience

Question 10

An organization wants to implement a hashing algorithm for integrity checks. Which of the following should be avoided due to known vulnerabilities? (Select TWO)

Accepted Answer

MD5. MD5 is correct because it is a widely deprecated hashing algorithm with known collision vulnerabilities, making it unsuitable for integrity checks. Practical collision attacks (e.g., using a chosen-prefix collision) can be executed in seconds on commodity hardware, so any integrity check relying on MD5 can be trivially bypassed.

Answer

SHA-3

Answer

SHA-256

Answer

HMAC-SHA256

Question 11

Which of the following encryption algorithms is classified as a symmetric block cipher and is the current standard recommended by NIST, supporting key sizes of 128, 192, and 256 bits?

Accepted Answer

AES. AES (Advanced Encryption Standard) is a symmetric block cipher that encrypts data in fixed 128-bit blocks and is the current standard recommended by NIST (FIPS 197). It supports key sizes of 128, 192, and 256 bits, making it the correct answer for a symmetric block cipher with those specific key lengths.

Answer

RSA

Answer

3DES

Answer

ChaCha20

Question 12

A security engineer is implementing a digital signature scheme to ensure non-repudiation. Which process correctly describes how a digital signature is created and verified?

Accepted Answer

Sign with private key, verify with public key. A digital signature is created by hashing the message and then encrypting that hash with the signer's private key. Verification is performed by decrypting the signature with the signer's public key and comparing the result to a freshly computed hash of the message. This asymmetric process ensures non-repudiation because only the private key holder could have created the signature, while anyone with the public key can verify it.

Answer

Sign with public key, verify with private key

Answer

Sign with symmetric key, verify with asymmetric key

Answer

Sign with hash, verify with private key

Question 13

Which of the following is a cryptographic hash function that is considered cryptographically broken due to collision attacks and should not be used for security purposes?

Accepted Answer

SHA-1. Both SHA-1 and MD5 are considered cryptographically broken due to collision attacks and should not be used for security purposes. SHA-256 and SHA-3 are still considered secure.

Answer

SHA-256

Answer

SHA-3

Question 14

What is the minimum recommended RSA key size for secure use as of current best practices?

Accepted Answer

2048 bits. (2048 bits) is correct because current best practices, as recommended by NIST SP 800-57 and other cryptographic standards, consider 2048-bit RSA keys as the minimum secure size for protecting data through 2030. This key length provides a sufficient security margin against known factoring attacks, balancing computational efficiency with cryptographic strength.

Answer

1024 bits

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4096 bits

Answer

3072 bits

Question 15

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 16

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 17

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 18

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 19

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

Accepted Answer

MD5. MD5 is known to have collision vulnerabilities and is no longer considered secure.

Answer

SHA-3

Answer

SHA-256

Answer

HMAC-SHA256

Question 20

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