Standards & Security
What Does Tamper Evident Mean?
The concept of tamper visibility.
Direct answer
Tamper evident describes a design feature that makes unauthorized opening, removal or manipulation of a product or closure point visible. A tamper-evident seal does not necessarily prevent an attack; its purpose is to make evidence of interference detectable.
What you will learn
Tamper evident means making interference visible; it does not mean tamper proof or impossible to attack.
Breaking, cutting, deformation, wire fraying or a color/surface change can provide tamper evidence.
Good design makes normal-use damage and suspicious tampering as distinguishable as possible.
A serial number adds an identity layer to physical tamper evidence.
A tamper-evident product has limited value without an inspection procedure.
Tamper evident vs. tamper resistant
The primary goal of a tamper-evident design is to leave visible evidence after interference. Tamper resistant describes features that make interference more difficult. A product can have both properties, but they are not the same concept.
For example, a thin plastic seal that is easy to cut is not a strong physical barrier, but it can be a good tamper-evident control because cutting irreversibly changes it and its serial number can be matched to records. Conversely, a strong metal fastener may resist force yet provide weak tamper evidence if it can be opened and restored without visible change.
Examples of tamper evidence
| Seal type | Normal condition | Suspicious sign |
|---|---|---|
| Plastic strap seal | Intact strap and lock | Cut, heat mark, bonding, lock deformation |
| Cable seal | Intact cable and locking body | Frayed strands, crushing, re-crimping signs |
| Bolt seal | Pin/body intact with matching numbers | Cut/manipulated pin, damaged body, number mismatch |
| Meter seal | Wire route and lock intact | Wire splice, break or body-opening signs |
Four elements of a good tamper-evident control
- Irreversible physical change when tampered with
- Clear visual criteria that an inspector can understand
- Serial number or other unique identity where needed
- Procedure defining application, inspection and exception handling
How to perform a tamper-evident inspection
- 1
Verify the correct product/number
Match the physical seal identity to the document or system record.
- 2
Inspect the locking area
Look for opening, heating, bonding, crushing or re-crimping signs.
- 3
Inspect strap/wire/pin end to end
Inspect the entire connecting element, not just the body.
- 4
Open an exception event if suspicious
Document the investigation with photos, serial number and handover information.
Frequently asked questions
What does tamper evident mean?
It means a design that provides visible evidence when a product or closure is opened or manipulated.
Is it the same as tamper proof?
No. Tamper evident makes interference visible; it does not claim to make interference impossible.
Is a serial number part of tamper evidence?
It is a separate identity layer from the physical tamper-evident feature, but it strengthens control by helping detect substitution with another product.
Is a broken seal definitive proof of tampering?
A broken seal is an event/tamper indicator, but authorized opening, accident or incorrect application can also cause it. Evaluate it with event records and other evidence.
How is tamper-evident performance tested?
Depending on product and requirement, visual tampering scenarios, lock integrity and physical performance are evaluated. Where a standard applies, use the test methods defined by that standard.
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