knowngood

Known-good or known-good state is a term used in information technology to describe an artifact, build, or state that has been verified to function correctly and to be free of identified defects at a given time. The concept serves as a baseline against which current systems, documents, or configurations can be compared to detect changes, corruption, or tampering.

In IT operations and disaster recovery, a known-good baseline or image (often called a golden image) is prepared and tested. If systems become unstable or compromised, administrators can restore from this known-good image to return to a trusted state. Integrity verification commonly relies on cryptographic hashes, digital signatures, or checksums to confirm that files or configurations match the known-good reference.

In software development, a known-good build or baseline represents a version that passes the full suite of tests and is regarded as a trustworthy reference for regression testing. New changes are compared against this baseline to identify introduced defects or incompatibilities.

In security, known-good baselines help detect unauthorized changes by alerting when files, binaries, or configurations diverge from the trusted reference. In hardware and manufacturing, a known-good test confirms that components or assemblies operate correctly before proceeding to higher levels of assembly.

The term is frequently used interchangeably with known-good state, known-good image, or golden master, though some contexts prefer the hyphenated form known-good. Related concepts include baselines, hash-based integrity checks, and file integrity monitoring.