Timestamps and provenance
Hashes and what they prove
International
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Background
The short answer
A hash is a fixed-length fingerprint of a file. The same file always gives the same hash; any change, however small, gives a different one. A hash proves identity between two copies of a file. Combined with a timestamp, it proves that this exact file existed at that time. Alone, it proves nothing about time.
Applies to: International. Assumes: a general, non-technical reader.
One-way by design
You cannot reconstruct the file from the hash, which is why a hash can be published or anchored without disclosing anything.
The pairing that matters
Hash plus timestamp is the atomic unit of digital evidence: identity plus date. Everything else in this library is commentary on that pair.
Sources
- 1.