Hashing

The hashing nodes compute content hashes of a media file. They are the foundation of asset identity in MetaLoom: the SHA-512 hash is the content key used to look an asset up, avoid recomputation, and match against blacklists. Four kinds live in the same module and can be toggled independently.

Kinds

md5, sha256, sha512, chunk-hash

Applies to

Any file

Inputs

None (typically the first processing step after the source)

Output keys

md5, sha256, sha512 (String); chunk_hash (String)

Requirements

CPU only. Streams the file, so memory use is low regardless of file size. Reads the full file bytes from storage.

Persists to

asset row hash columns + asset_node_result ledger

chunk-hash computes a content-based chunked hash used for near-duplicate detection on partially modified files.

Configuration

Per-node options (HashNodeOptions) enable each algorithm individually:

Option Default Meaning

md5

off

Compute the MD5 hash

sha256

off

Compute the SHA-256 hash

sha512

on

Compute the SHA-512 hash (the system-wide content identity)

chunkHash

off

Compute the chunked content hash

In online mode a hash node checks Loom first and short-circuits when the hash is already stored.

Use Cases

  • Asset identity — resolve an asset by its SHA-512 across the platform.

  • Exact deduplication — find byte-identical files (see Deduplication).

  • Near-duplicate detection — chunk-hash flags files that were partially modified.

  • Blacklisting — match incoming media against a hash blacklist.