as a subcharacteristic, and "interoperability" and "security" are moved elsewhere. "Accuracy" is renamed "functional correctness", and "suitability" is renamed "functional appropriateness". "Efficiency" is renamed "performance efficiency". "Capacity" is added as a subcharactersitic. "Compatibility" is a new characteristic, with "co-existence" moved from "portability" and "interoperability" moved from "functionality". "Usability" has new subcharacteristics of "user error protection" and "accessibility" (use by people with a wide range of characteristics). "Understandability" is renamed "appropriateness recognizability", and "attractiveness" is renamed "user interface aesthetics". "Reliability" has a new subcharacteristic of "availability" (when required for use). "Security" is a new characteristic with subcharacteristics of "confidentiality" (data accessible only by those authorized), "integrity" (protection from unauthorized modification), "non-repudiation" (actions can be proven to have taken place), "accountability" (actions can be traced to who did them), and "authenticity" (identity can be proved to be the one claimed). "Maintainability" has new subcharacteristics of "modularity" (changes in one component have a minimal impact on others) and "reusability"; "changeability" and "stability" are rolled up into "modifiability". "Portability" has "co-existence" moved elsewhere. See also CISQ ISO/IEC 25010 ISO 9000 Verification and Validation Non-functional requirements Squale ISO/IEC JTC 1/SC 7 Software quality References Scalet et al., 2000: ISO/IEC 9126 and 14598 integration aspects: A Brazilian viewpoint. The Second World Congress on Software Quality, Yokohama, Japan, 2000. Software quality 09126 09126