The integrity of the unit price is the most critical classification aspect. Integrity ensures that the price data is accurate, complete, and has not been altered without authorization. An incorrect price, whether due to error or malicious attack, can lead to significant financial losses for the company (e.g., selling products at a fraction of their cost) or a complete loss of sales and customer trust (if priced too high). While availability is crucial for a 24-hour service, the consequences of an integrity failure for financial data are typically more severe and damaging to the business's viability than a temporary loss of availability.

A. Confidentiality: The unit price in a public webshop is public information intended for all visitors; therefore, confidentiality is the least important concern.

C. Availability: While the price must be available for a sale to occur, an available but incorrect price (an integrity failure) can cause more significant financial and reputational damage.

1. ISO/IEC 27000:2018, Information technology — Security techniques — Information security management systems — Overview and vocabulary.

Section 3.28: Defines integrity as the "property of accuracy and completeness." For transactional data like pricing, accuracy is paramount to prevent financial loss and maintain business viability. The standard emphasizes that the importance of C, I, and A depends on the context, and for financial data, integrity is typically the highest priority.

2. NIST Special Publication 800-53 Revision 5, Security and Privacy Controls for Information Systems and Organizations.

Appendix F, Security Control Catalog, SI-7 Software, Firmware, and Information Integrity: This control family highlights the need to protect the integrity of information at all points in its lifecycle. The document implicitly supports that for data like pricing, where accuracy directly impacts financial outcomes, integrity controls are of the highest importance. The impact of an integrity loss is often categorized as high or catastrophic for financial systems.

3. Saltzer, J. H., & Schroeder, M. D. (1975). The Protection of Information in Computer Systems. Communications of the ACM, 18(7), 387-408.

Section A.3: Design Principles, Complete Mediation: This foundational paper in computer security discusses principles that support data integrity. While not using the term "integrity" in the modern sense, the principle of checking every access to every object is fundamental to preventing unauthorized modification of critical data like price, underscoring its importance over simple availability. The consequences of acting on incorrect data are highlighted as a primary security concern.