Tamper-evident, not tamper-proof
It is worth being precise, because the words get used loosely. Tamper-proof claims a record can never be altered. Almost nothing real meets that bar, and claiming it invites challenge. Tamper-evident is the standard that matters: a record may be alterable, but no alteration can happen without being detectable. That is exactly the property a worked-hour record needs to carry weight in a dispute — not a promise that nothing ever changes, but proof that nothing changed without being seen.
The three properties that create tamper-evidence
Tamper-evidence is not a single feature you switch on. It is the combination of how a record is made and how it is sealed.
- Captured at the source: the hours are recorded at the point and time of work, not typed up later from memory or a paper note.
- Independently approved: the shift is confirmed by someone other than the worker — typically the site supervisor — so the record is not self-attested.
- Cryptographically sealed: the finalised record is hashed and written to an append-only log, so any later change produces a different hash and is detectable.
- Correction without erasure: amendments are made as new, logged entries that preserve the original, rather than overwriting it.
Why a spreadsheet fails the test
The most common worked-hour record in labour hire is a spreadsheet, sometimes exported to a PDF that looks official. Neither is tamper-evident. A spreadsheet can be changed by anyone with access, and the change leaves no reliable trace of what the figure was before or who altered it. A PDF freezes an appearance, but it is generated from underlying data that can itself be edited and re-exported. Looking fixed is not the same as being provably unchanged.
| Spreadsheet or PDF | Tamper-evident record | |
|---|---|---|
| Who can change it | Anyone with access | Only through a logged correction |
| Is a change detectable | No reliable trace | Yes — the seal no longer matches |
| Original after a correction | Overwritten and lost | Preserved alongside the amendment |
| Who confirmed the hours | Usually unrecorded | The approving supervisor, recorded |
| Weight if challenged | Easily disputed | Settled on the record |
How Flostruction makes hours tamper-evident
Tamper-evidence is the whole point of an evidentiary record. A record you can quietly change is not evidence of anything.
Flostruction captures each shift on site, has the supervisor approve it, and seals the approved record under the Workforce Ledger Evidentiary Standard (WLES) — an open standard for verifiable, portable, tamper-evident worked-hour records. The original hours and any later correction are both preserved, and the seal makes any change detectable. The result is a defensible timesheet that holds up because it can be shown to be unchanged, not merely asserted to be.
Tamper-evident timesheets: FAQ
What makes a timesheet tamper-evident?
A timesheet is tamper-evident when any change to a finalised record can be detected after the fact. In practice that means the hours are captured when the work happens, approved by someone independent of the worker, and then sealed — typically with a cryptographic hash and an append-only log — so a later edit either fails or leaves a visible trace rather than silently overwriting the original.
Is a spreadsheet or a PDF tamper-evident?
No. A spreadsheet can be edited by anyone with access and leaves no reliable trace of what changed or when. A PDF looks fixed but can be regenerated from altered source data. Neither proves that the hours shown are the hours that were originally recorded, so neither is tamper-evident in any meaningful sense.
Tamper-evident or tamper-proof — what is the difference?
Tamper-proof claims a record cannot be altered at all, which is rarely true of any real system. Tamper-evident is the honest and useful standard: alteration may be possible, but it cannot happen without being detectable. For worked-hour records, tamper-evidence is what gives a record evidentiary weight.
Why do tamper-evident timesheets matter for labour hire?
Because the cost of an unprovable hour falls on the labour hire employer, and because corrections are normal — a shift gets adjusted, a break is added. A tamper-evident record preserves both the original entry and any later correction, so the record can be trusted even though it can be amended through a proper, logged process.
Sources: Fair Work Ombudsman, Record-keeping and pay slips; the Workforce Ledger Evidentiary Standard specification.