CISSP Software Development Security Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Using industry-standard algorithms (e.g., AES-256)

  Why this is correct

  Industry-standard cryptographic algorithms like AES-256 undergo extensive public scrutiny and cryptanalysis by experts worldwide. This rigorous vetting process helps identify and mitigate potential vulnerabilities, ensuring their robustness against known attack methods and providing a high level of confidence in their security. Relying on such well-established algorithms is fundamental for achieving strong confidentiality and integrity in data protection, as opposed to proprietary or unproven methods.

• ✓

  Implementing proper key management practices

  Why this is correct

  Proper key management practices encompass the entire lifecycle of cryptographic keys, including secure generation, storage, distribution, rotation, revocation, and destruction. If keys are compromised due to weak management, even the strongest encryption algorithms become ineffective, rendering all encrypted data vulnerable to unauthorized access. Secure key management is paramount for maintaining the confidentiality and integrity of encrypted information throughout its existence and is often the weakest link in an otherwise strong cryptographic system.

• ✓

  Using authenticated encryption (e.g., AES-GCM)

  Why this is correct

  Authenticated encryption modes, such as AES-GCM (Galois/Counter Mode), provide both confidentiality and data integrity, along with authenticity. Confidentiality ensures that unauthorized parties cannot read the data, while integrity guarantees that the data has not been tampered with during transit or storage. This combined protection is critical, as data modification without detection can be as damaging as unauthorized disclosure, preventing various active attacks like bit-flipping or replay attacks.

• ✗

  Hashing the data with MD5 for faster performance

  Why it's wrong here

  Hashing data with MD5 is fundamentally inappropriate for encryption purposes because MD5 is a one-way cryptographic hash function, not an encryption algorithm. It is designed for integrity checks, not confidentiality, and cannot be reversed to recover the original data. Furthermore, MD5 is cryptographically weak, highly susceptible to collision attacks where different inputs produce the same hash, making it unsuitable even for integrity verification in security-critical applications.

• ✗

  Using a static IV for simplicity

  Why it's wrong here

  Using a static Initialization Vector (IV) for simplicity is a critical cryptographic vulnerability that severely compromises confidentiality. An IV must be unique for each encryption operation, ideally random or a nonce, to prevent identical plaintext blocks from producing identical ciphertext blocks when using block cipher modes like CBC or CTR. A static IV allows attackers to deduce relationships between encrypted messages, facilitating chosen-plaintext attacks and potentially leading to full plaintext recovery.

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