Question

Difficulty: MediumCIA Triad and Non-Repudiation

A healthcare organization requires that when physicians approve electronic prescription orders, the system must generate proof of origin so that a physician cannot later deny authorizing the order. To accomplish this, the system applies a digital signature using the physician's private key combined with a cryptographic hash of the order details. Which security concept is directly fulfilled by implementing digital signatures to prevent denial of origin?

  1. Non-repudiationAnswer
  2. B
    Integrity alone
  3. C
    Authorization
  4. D
    Symmetric confidentiality

Answer

Non-repudiation is the primary security goal achieved, as digital signatures bind an identity to a specific transaction using asymmetric cryptography so the sender cannot deny authorizing it.
The correct concept is non-repudiation. Digital signatures combine asymmetric cryptography (signing with the sender's private key) and cryptographic hashing to provide both authenticity of origin and data integrity. Because only the physician possesses their private key, they cannot claim a signed order was generated by someone else.

Step-by-Step Solution

1
Analyze the scenario requirement
The scenario requires preventing an individual (the physician) from denying that they approved a specific electronic prescription order.
Identifying the core business and security goal isolates which security pillar or principle is being tested.
2
Evaluate the technical control described
The control uses asymmetric key pairs (private key signing) combined with a cryptographic hash of the payload.
A cryptographic hash guarantees integrity (tamper-resistance), while signing with a private key uniquely ties the data to the key holder's identity.
3
Map the technical control to the core security concept
Combining integrity verification with cryptographic proof of identity yields non-repudiation.
Non-repudiation ensures that a party to a contract or communication cannot successfully challenge the authenticity of their signature or transaction.

Key Concept

Non-repudiation and CIA Triad
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