manifestsha256

Manifestsha256 refers to the SHA-256 cryptographic hash of a manifest document. A manifest is a data structure or file that describes a set of software artifacts, such as image layers, configuration, or packaged files. The manifestsha256 serves as a content-addressable identifier, uniquely representing the exact content of that manifest. If the manifest changes, the resulting SHA-256 hash changes.

In container ecosystems, particularly those aligned with the OCI (Open Container Initiative) or Docker image formats, the image manifest is a JSON document that specifies metadata, a list of layers, and references to configuration. The digest of this manifest is the SHA-256 hash of its canonical JSON representation. This digest is used to pin or verify images; an image can be referenced by its digest (for example, sha256:<digest>) rather than by a mutable tag. Registries may publish the digest in response headers such as Docker-Content-Digest.

Computing a manifestsha256 typically involves hashing the manifest file’s bytes with the SHA-256 algorithm, for example using a command such as sha256sum on Linux or a cryptographic library. The resulting value is usually written as sha256:<hex>.

Applications rely on manifestsha256 to ensure integrity and reproducibility, since the hash will only match if the manifest content is identical. It also enables content-addressable storage and efficient caching, supporting verification, caching, and immutable references.

See also: OCI image format, Docker Registry HTTP API v2, content-addressable storage, digest.