Independent Verification.
Verify the integrity of a file referenced by a Digital Witness Certificate using only the standard tools shipped with macOS, Linux, or Windows. No Witnium software required.
"Is the file presented now identical to the file referenced in the Digital Witness Certificate?"
Established by computing the file's cryptographic hash locally and comparing it to the hash recorded at witness time.
Identify the recorded hash.
In the Digital Witness Certificate, locate the field labelled File Integrity Hash or SHA-256 Hash.
This value represents the file's cryptographic fingerprint at the time it was witnessed.
Open a command-line interface.
- •macOS — open Terminal (Applications → Utilities → Terminal).
- •Windows — open PowerShell.
- •Linux — open Terminal.
Navigate to the file location.
Change directory to the folder containing the file.
cd DownloadsAdjust the path as needed.
Compute the file's SHA-256 hash.
macOS
shasum -a 256 filename.extLinux
sha256sum filename.extWindows (PowerShell)
Get-FileHash filename.ext -Algorithm SHA256Replace filename.ext with the actual file name.
Review the output.
The command produces a SHA-256 hash value, for example:
This is the fingerprint of the file in its current state.
Compare the hash values.
Compare the locally computed hash with the hash recorded in the certificate.
Letter case (uppercase/lowercase) is not significant; all characters must otherwise match exactly.
Scope of what this verification establishes.
This verification establishes:
- ✓That the file's content has not changed since the moment it was witnessed.
It does not determine:
- ×Authorship.
- ×Legal ownership.
- ×Intent or purpose.
Want this in front of a regulator or court?