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Difficulty: MediumCryptographic Concepts and Algorithms

A security engineer is updating the firmware verification process for remote, low-power industrial sensor gateways. The firmware update image must be digitally signed by the vendor to verify its origin and integrity before installation. Due to severe memory and processing constraints on the gateway hardware, the solution must provide strong asymmetric security while minimizing key size and computational overhead. Which cryptographic algorithm combination should the engineer select?

  1. Elliptic Curve Digital Signature Algorithm (ECDSA) with SHA-256Answer
  2. B
    RSA-4096 with SHA-512
  3. C
    HMAC-SHA256 using a pre-shared key distributed to all gateways
  4. D
    AES-256 in Galois/Counter Mode (GCM)

Answer

Elliptic Curve Digital Signature Algorithm (ECDSA) with SHA-256
Elliptic Curve Digital Signature Algorithm (ECDSA) paired with SHA-256 satisfies the requirement for asymmetric digital signatures (enabling non-repudiation and origin authenticity verification) while offering significantly smaller key lengths and lighter computational demands than traditional algorithms like RSA. This makes it the ideal choice for low-power embedded devices.

Step-by-Step Solution

1
Identify the primary cryptographic requirement.
Digital signatures (asymmetric cryptography) are required to verify vendor origin and guarantee non-repudiation.
Symmetric approaches like pre-shared keys or symmetric ciphers cannot prove origin authenticity to third parties without sharing private keys.
2
Evaluate hardware constraints.
The target edge hardware has low processing power and constrained memory.
Large key asymmetric algorithms such as RSA-4096 introduce significant processing latency and memory requirements.
3
Select the optimal lightweight asymmetric signature scheme.
ECDSA combined with SHA-256 provides robust non-repudiation and integrity verification with minimal computational overhead.
Elliptic Curve Cryptography (ECC) achieves high cryptographic strength using much shorter keys than RSA.

Key Concept

Asymmetric Digital Signatures & Elliptic Curve Cryptography
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Topics

Cryptographic Concepts and Algorithms

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