SECTION / 01

File counts are useful but insufficient

Matching totals can reveal obvious omissions, but two different file sets can have the same count. Counts are an inventory signal, not proof of content equality.

SECTION / 02

Readable files versus files merely existing

A directory entry can exist while the underlying archive entry is incomplete, unsupported or unreadable. Surface these conditions separately instead of collapsing every problem into “corrupt”.

SECTION / 03

What checksums prove

A SHA-256 fingerprint is derived from file content. When source and destination fingerprints match, the copied bytes match. The fingerprint does not prove artistic quality, correct metadata or that Nikon supplied every expected photograph.

SECTION / 04

Exact duplicate-content detection

Matching fingerprints can identify byte-for-byte duplicate content across different filenames and folders. It does not classify near-duplicates or choose which copy a person should keep.

SECTION / 05

Source and destination comparison

Verification should check every expected destination item for presence, expected size and matching SHA-256. A missing or mismatched item keeps the overall result from becoming VERIFIED.

SECTION / 06

Why originals should remain untouched

The original download is your baseline. If organisation or copy work goes wrong, an immutable source lets you start again and explain what changed.

SECTION / 07

Why a second independent copy matters

Verification protects against copy errors; another independent location protects against device loss, theft, failure or disaster. A resilient archive needs both.

SECTION / 08

Photo Archive Rescue verification workflow

Open one ZIP or folder, review inventory and issues, preview an organised destination, copy to a separate location, then require destination presence, size and SHA-256 equality for every expected item before showing green VERIFIED.

EVIDENCE / SOURCES

Sources and boundaries

  • Secure Hash Standard (FIPS 180-4)National Institute of Standards and TechnologyPrimary specification for SHA-256.
    Open source ↗