A security architect is designing a system for secure communication between two IoT devices over an unreliable network. They need a cryptographic primitive that provides both data confidentiality and data integrity, while also allowing for efficient processing on resource-constrained devices. Which type of cryptographic algorithm is best suited for this combined requirement?
- ASymmetric-key block cipher with a separate hashing algorithm
- BAuthenticated Encryption with Associated Data (AEAD)
- CDigital signature algorithm
- DAsymmetric-key encryption
Show answer & explanationAnswer & explanation
Correct answer: B. Authenticated Encryption with Associated Data (AEAD)
AEAD modes (like GCM or CCM) combine encryption for confidentiality and message authentication codes (MACs) for integrity and authenticity into a single, efficient cryptographic primitive. This avoids the complexities and potential pitfalls of 'encrypt-then-MAC' or 'MAC-then-encrypt' schemes, making it ideal for resource-constrained devices needing both confidentiality and integrity.
Why the other options are wrong
- A. While possible, combining a block cipher and a separate hash function correctly is complex and prone to implementation errors.
- C. Digital signatures provide integrity and non-repudiation but not data confidentiality by themselves.
- D. Asymmetric-key encryption is too computationally intensive for bulk data encryption on resource-constrained IoT devices.
Authenticated Encryption with Associated Data (AEAD)
A type of encryption that simultaneously provides confidentiality (data privacy), integrity (data hasn't been altered), and authenticity (data comes from the expected source). It can also authenticate 'associated data' that is not encrypted.
- Combines encryption and message authentication.
- Prevents common cryptographic implementation pitfalls.
- Often more efficient than separate encryption and MAC schemes.
Memory trick: AEAD is like a secure, tamper-proof envelope for your IoT messages.