Untrusted

Untrusted is an adjective used to describe something that is not regarded as trustworthy or credible. In everyday usage, it may refer to a person, source, or system lacking proven reliability, evidence, or integrity. The term conveys doubt about safety, authenticity, or motive, and does not inherently condemn but indicates uncertainty that requires verification.

In computing and information security, untrusted denotes data, code, or environments that lie outside a defined trust boundary and therefore cannot be assumed safe. Typical examples include input from users or external networks, third-party libraries, or unverified software. Handling untrusted content often requires defensive measures such as input validation and sanitization, strict type checking, and the principle of least privilege. Systems may isolate, sandbox, or run untrusted code in restricted environments to prevent breaches or unauthorized access. Certification, digital signatures, and reputation-based trust models are used to reduce the risk associated with untrusted sources.

In governance and journalism, untrusted claims or sources are treated with caution and require corroboration. The concept underscores the importance of provenance, evidence, and verification in information ecosystems. Related terms include trusted, trustworthiness, trust boundary, and sandbox.