How do I check if an evidence package was tampered with?

Recompute the SHA-256 hash of every file and compare it with manifest.json, then check the RSA signature over manifest.json. The Trust Verifier on getproofsnap.com and the scripts in the ZIP do both. A changed or missing file changes the verdict to Integrity: modified and names the file.

Does a valid signature prove who captured the page?

No. The signing key is generated inside the package, so a valid signature proves that the files have not changed since the package was sealed. The OpenTimestamps and eIDAS timestamps are what prove when.

Is the online Trust Verifier free?

Yes. Anyone can open the Trust Verifier in a browser and drop the ZIP, with no account and no installation. The ZIP is opened in the browser; only the manifest, its hash and the timestamp tokens go to ProofSnap's verification service for the Bitcoin and eIDAS checks.

Which file do I give to the other side or the court?

The ZIP exactly as you downloaded it from the side panel. Everything needed for verification is inside, including the scripts and the guide. You can send the evidence document separately for reading, but the ZIP is the evidence.

Does verification need ProofSnap or an account?

Only route A does. The Trust Verifier on this website works for anyone without an account, and the scripts in the ZIP need no ProofSnap at all.

Does a pending Bitcoin timestamp mean the package is not valid?

No. The verdict can be Integrity: match while the Bitcoin anchor is still pending. Verify the same ZIP again a few hours later to see the block.

How to Verify a ProofSnap Evidence Package: 3 Ways (2026)

Three ways to verify

All three check the same thing: that every file is the one that was sealed at capture time, and which timestamps prove when. Pick the one that suits the person doing the checking.

Route A · Steps 2 to 6

In the ProofSnap side panel

For you, right after the capture or before you send the package. Needs ProofSnap and a sign-in.

Route B · Step 7

On this website

For the other side, a court or anyone else. Any browser, no installation, no account.

Route C · Steps 8 to 10

With the scripts in the ZIP

For an expert who wants a check that runs on their own computer, independent of ProofSnap.

What a successful verification proves

Verifying a ProofSnap evidence package answers three separate questions. Integrity: every file still has the SHA-256 hash recorded in manifest.json. Coherence: the RSA signature in manifest.sig matches the manifest, so the list of hashes was not edited either. Time: an OpenTimestamps proof shows the manifest existed no later than a given Bitcoin block. An EU qualified timestamp from Disig a.s., a Qualified Trust Service Provider on the EU Trusted List, ties it to a date and time.

"The TSA's role is to time-stamp a datum to establish evidence indicating that a datum existed before a particular time."

IETF RFC 3161, Time-Stamp Protocol, section 1 (2001)

The signature proves integrity: its key is generated inside the package, and the timestamps prove time. The scripts verify.sh and verify.ps1 run the same four checks (file integrity, manifest signature, eIDAS token, Bitcoin anchor) and end with one of three exit codes: 0 for PASS, 1 for FAIL and 2 for INCOMPLETE.

The three routes compared

The side panel verifier reads packages up to about 1.8 GB, and browser memory can run short from about 900 MB. For larger packages, use verify.sh or verify.ps1, which check any size file by file.

	A: side panel	B: website	C: scripts in the ZIP
Who uses it	You, before sending	Anyone you send it to	An expert on their own computer
ProofSnap account	Required	Not needed	Not needed
Runs on	Chrome or Edge with ProofSnap	Any modern browser	macOS, Linux, Windows
Uses ProofSnap servers	For the two timestamp checks	For the two timestamp checks	No
Large videos	Up to about 1.8 GB	Limited by browser memory	No size limit

Step 1, everyone

Work with the original ZIP

Every route below checks the ZIP exactly as ProofSnap produced it, whether it holds a web capture, a video, a multi-tab session or a file certification. That ZIP is also what you hand over to the other side, your lawyer or the court. Keep the original untouched and work on copies. What each file contains is explained in how to read an evidence package.

1The ZIP. Renaming the ZIP file itself is harmless: the checks look at the files inside. Do not add files to it, remove files from it or zip it again.
2manifest.json. The list of every file with its SHA-256 hash, signed in manifest.sig with the key in publickey.pem. When present, the Bitcoin and eIDAS timestamps are issued for this file.
3verification/. The scripts and the plain-text guide for checking the package without ProofSnap, see steps 8 to 10.

1 proofsnap_20261015_094107.zip

evidence.pdf
provenance_certificate.pdf
screenshot.jpeg
page.html
page.mhtml
domtextcontent.txt
metadata.json
c2pa.json
chain_of_custody.json
forensic_log.json
forensic_log_summary.txt
2manifest.json
manifest.sig
publickey.pem
manifest.json.ots
manifest.json.tsr
eidas_validation.json
3verification/
verify.sh
verify.ps1
VERIFICATION_GUIDE.txt

An example web capture package with OpenTimestamps and eIDAS, opened in a file manager (simplified). The exact list depends on the plan and the options.

Step 2, in the side panel

Find the ProofSnap Trust Verifier

Open the ProofSnap side panel and scroll down past the capture options. The ProofSnap Trust Verifier card sits right above the File Certifier and starts collapsed. You need a ProofSnap account with a plan or credits to see it; anyone without ProofSnap uses the website (step 7).

1ProofSnap icon. Opens the side panel. The tab you have open does not matter.
2ProofSnap Trust Verifier. Click the title to open the card.

Step 3, in the side panel

Upload the ZIP and click Verify zip file

The verifier accepts a web capture or video package, a session package, a file certification, a combined certification of several files and a batch package with one ZIP per file. It works out the type from the manifest by itself.

1Click to upload or drag and drop. Pick the ZIP. Its name appears in blue under the drop area.
2Verify zip file. Runs all checks in your browser. The two timestamp checks query ProofSnap's verification service, so stay online. Very large packages (from about 900 MB, typically long videos) may run out of browser memory; above about 1.8 GB the verifier refers you to the scripts in step 8.

The card open, with the ZIP selected. Until you pick a file, the button stays grayed out and cannot be clicked.

Step 4, in the side panel

Read the verdict

The verdict sums up all checks in one line. Hover over it to see a short explanation.

1Integrity: match. All cryptographic checks passed: the files match the manifest, and the manifest matches the signature made with the key in the package. The verifier shows it only after it has actually checked the signature and recomputed the file hashes.
2Integrity: modified. The evidence has been altered or is incomplete: at least one check failed. See the section on what to do below.
3Show technical verification. Opens the individual checks (next step).

Top: an intact package. Bottom: the same place when a check failed.

Step 5, in the side panel

Open the technical verification

Each line is one check. A blue bar means passed or for information, a red bar means failed. Which lines appear depends on what the package contains.

1manifest.json. The RSA signature over the manifest checks out with the public key in the package. It proves the manifest has not changed since it was signed.
2File Integrity. Every file listed in the manifest is hashed again with SHA-256 and compared. The signature and the key are written after the manifest, so they are checked for presence. Session packages include the files of every tab, video packages the recording.
3Chain of custody. The capture time is plausible (not in the future, not older than 30 years), forensic_log.json matches the hash recorded in chain_of_custody.json, its hash chain is recomputed step by step, and the final chain hash matches. The line naming the ISO standard repeats what chain_of_custody.json declares; it is not an assessment.
4Capture context. Extension version, how many time servers confirmed the capture time, the device integrity score and the number of recorded operations. A session package also lists every tab it covers.

The timestamp lines

5OpenTimestamps. The Bitcoin block the manifest is anchored in and its date. Shortly after a capture this line says pending (see step 11). Not on Essential captures unless an eIDAS or Video SnapPack credit was used.
6EU Qualified Timestamp. The qualified timestamp is valid for this manifest: issuer and time in UTC. Disig a.s. is a Qualified Trust Service Provider on the EU Trusted List.
7EU Qualified Timestamp (LTV). A second check that needs no server: hash, signature, certificate chain and revocation status, all from eidas_validation.json in the package. If the eIDAS service cannot be reached, this check runs on its own.
8Issuer. A reminder that the signing key is generated inside the package: the signature proves integrity, the timestamps prove time.

Integrity: match

Hide technical verification

1

manifest.json: Signature is valid. The file was signed using the provided public key, and the signature matches the manifest contents.

2

File Integrity: All 16/16 files verified: SHA-256 hashes match manifest.

3

Capture timestamp is within reasonable range (2026-10-15T09:41:07.000Z)

forensic_log.json: Verified: hash matches chain of custody reference.

Hash Chain: Integrity verified - tamper-evident log chain is intact

Chain Hash: Final hash matches Chain of Custody reference

chain_of_custody.json: Compliant with ISO/IEC 27037:2012 (guidance, not a certifiable standard)

4

Extension Integrity: Verified (v1.19.5)

NTP Time: Cross-verified by 3 of 3 sources

Device Integrity: Passed (Score: 100/100)

Forensic Log: 27 operations in 21.38 seconds (NTP synchronized)

5

OpenTimestamps: Verified. Anchored to Bitcoin block 970418, confirming existence as of 2026-10-15 +04 (UTC).

6

EU Qualified Timestamp: Verified. TSA: Disig a.s., Timestamp: 2026-10-15T09:41:12Z.

7

EU Qualified Timestamp (LTV): Offline validation passed (hash, signature, certificate chain, OCSP).

8

Issuer: this package is signed with a key generated inside the package.

Technical verification of the example package, a few hours after the capture. Values are examples.

Step 6, file certifications

Check the original file against the certificate

For a file certification the verifier adds a box that compares any file you drop on it with the certified hash. Use it to show that the copy you or the other side hold today is the very file that was certified. The file is hashed in your browser and not uploaded.

1The certification ZIP. Verify it first, as in steps 3 to 5.
2Verify original file matches certificate. Drop the original. File matches certificate means this file existed at the certified date and time. File does NOT match means the hash differs: this is not the file that was certified. You can drop several files at once, for example the originals of a combined certification.
3Verdict. Concerns the package itself, as for any other package.
4Package type. File Certification with the certified hash, or Combined File Certification with the number of files.

A file certification, with the original file dropped on the extra box. File name and hash are examples; the list goes on below.

Step 7, on the website

Verify on getproofsnap.com, no account needed

The other side, a court or an expert can open the ProofSnap Trust Verifier on this website in any browser, without ProofSnap and without an account. It runs the same kinds of checks and lists every result line by line. The ZIP is opened in the browser; for the Bitcoin and eIDAS checks the page sends the manifest, its hash and the timestamp tokens to ProofSnap's verification service.

1Drop the ZIP. Or click to choose it.
2Verify Evidence Package. Starts the checks.
3Verification Results. A blue check mark means the check passed, a dark X that it failed.
4Package details. Type, ID and capture time from the manifest.
5Manifest signature verified. Same check as in the side panel.
6Hash matches. One line per file. A changed file shows Hash mismatch, a missing one File missing.
7Chain of custody. Forensic log hash, hash chain, standard and device integrity.
8Timestamps. The Bitcoin block with its date in your local time, the eIDAS timestamp and the offline LTV check. For a single-file certification the page also checks the original file inside the ZIP automatically.

ProofSnap Trust Verifier

getproofsnap.com/verify/index.html

Verify Digital Evidence Integrity Online

1

Click to upload or drag and drop

ProofSnap ZIP evidence packages only

proofsnap_20261015_094107.zip

2

Verify Evidence Package

3

Verification Results

4Package type: web capture

Package ID: ps_7c1e4b2a-93f0-4d5e-b8a1-2f6c0d9e4a37

Captured: 2026-10-15 09:41:07 UTC

5Manifest signature verified

Issuer: this package is signed with a key generated inside the package.

6Hash matches: metadata.json

Hash matches: page.html

Hash matches: screenshot.jpeg

Hash matches: evidence.pdf

Hash matches: provenance_certificate.pdf

Hash matches: domtextcontent.txt

Hash matches: c2pa.json

Hash matches: page.mhtml

Hash matches: forensic_log.json

Hash matches: forensic_log_summary.txt

Hash matches: verification/verify.sh

Hash matches: verification/verify.ps1

Hash matches: verification/VERIFICATION_GUIDE.txt

Hash matches: chain_of_custody.json

7Forensic log hash matches Chain of Custody reference

Forensic log hash chain is valid (tamper-evident)

Final chain hash matches Chain of Custody reference

Chain of Custody: ISO/IEC 27037:2012 (guidance, not a certifiable standard)

Device integrity: Passed (score 100/100)

8OpenTimestamps: Verified at block 970418 (10/15/2026, 11:02:31 AM)

EU Qualified Timestamp: Verified. TSA: Disig a.s., Timestamp: 2026-10-15T09:41:12Z

EU Qualified Timestamp (LTV): Offline validation passed (hash, signature, certificate chain, OCSP)

The verifier on this website, simplified: browser and site header left out. Results of the same example package as in step 5.

Step 8, without ProofSnap

Run verify.sh on macOS or Linux

For a check that relies on nothing from ProofSnap, unzip a copy of the package and run the script inside it. It needs only what macOS and Linux already have: a shell, awk and a SHA-256 tool (shasum, sha256sum or openssl), plus openssl for the signature and eIDAS steps. It writes nothing into the package.

1Start it. From the unzipped folder: bash verification/verify.sh.
2File integrity. Recomputes the SHA-256 of every file the manifest lists: OK, MISMATCH or MISSING. A file in the folder that the manifest does not list is reported as NOT COVERED.
3Manifest signature. Checks manifest.sig with openssl. Verified OK is openssl's own answer.
4eIDAS. Compares the hash inside the qualified token with manifest.json, checks the root certificate in the package against the published fingerprint of CA Disig QCA4 and checks the token's signature. It prints the openssl command for the full certificate chain.
5OpenTimestamps. Prints the command to check the Bitcoin anchor with the OpenTimestamps client (ots), which you install separately.
6RESULT. PASS (exit code 0), FAIL when a check ran and did not pass (1), or INCOMPLETE when a tool was missing (2), which does not count against the package.

Terminal: ~/Downloads/proofsnap_20261015_094107

$ unzip -q proofsnap_20261015_094107.zip -d proofsnap_20261015_094107

$ cd proofsnap_20261015_094107

1$ bash verification/verify.sh

============================================================

ProofSnap Evidence Verification

============================================================

2[1/4] File integrity: SHA-256 of every file vs manifest.json

------------------------------------------------------------

OK metadata.json

OK page.html

OK screenshot.jpeg

OK evidence.pdf

OK provenance_certificate.pdf

OK domtextcontent.txt

OK c2pa.json

OK page.mhtml

OK forensic_log.json

OK forensic_log_summary.txt

OK verification/verify.sh

OK verification/verify.ps1

OK verification/VERIFICATION_GUIDE.txt

OK chain_of_custody.json

RESULT: all 14 hashed file(s) match

3[2/4] Manifest signature: RSA over manifest.json

------------------------------------------------------------

Verified OK

Signature OK: manifest.json matches the key in publickey.pem, so the

manifest has not been altered since it was signed. That key travels in

this package, so it shows internal coherence, not authorship; what ties

the manifest to a moment in time is a timestamp, and the steps below

report which timestamps this package carries.

4[3/4] eIDAS RFC 3161 qualified timestamp

------------------------------------------------------------

The qualified token carries the SHA-256 of manifest.json:

630b95a9f7831addbf2816e9fec450f59b15004c7138a3119584642e34b216ff

So manifest.json is the file the authority stamped, unchanged since.

The root offered for that check is in eidas_validation.json, which is

NOT covered by the manifest and could be replaced. Check it against the

published fingerprint of the authority before trusting it:

CA Disig QCA4, SHA-256

8E:BC:96:10:6E:FE:F2:7F:D3:69:D5:D8:5E:73:6E:4C:4E:31:DD:AC:22:E3:16:89:23:55:C5:3B:28:2E:C1:37

the root in this package matches that fingerprint.

The token's own signature verifies against the root in this package.

To check the token's own signature and its chain to that root:

openssl ts -verify -in manifest.json.tsr -data "manifest.json" -CAfile <tsa-root>.pem

The certificate chain, the OCSP response and the CRL gathered at

stamping time are in eidas_validation.json; its 'ocspStatus' field

carries the status of the TSA certificate. The root cert is the

'rootCaPem' field: copy its value into a .pem file and pass that

as -CAfile.

5[4/4] Bitcoin OpenTimestamps anchor

------------------------------------------------------------

manifest.json.ots present. Deep verify (needs the ots client):

ots verify manifest.json.ots -f "manifest.json"

============================================================

6 RESULT: PASS, the hashes match the manifest, the manifest signature

verifies, and the qualified token carries the hash of the file it

covers. What is left to the printed commands is the token's own

certificate chain, and the Bitcoin anchor.

============================================================

Simplified terminal on Linux with OpenSSL 3. Every line below the command is printed by verify.sh as written; the folder name and the hash are examples.

Step 9, without ProofSnap

Run verify.ps1 on Windows

Unzip a copy of the package, open PowerShell (version 5 or later) in that folder and run the command below. The script runs the same four steps as verify.sh.

1Start it. powershell -ExecutionPolicy Bypass -File verification\verify.ps1 from the unzipped folder.
2File integrity. Uses Windows' own Get-FileHash and also compares the SHA-512 values the manifest carries. This part needs nothing else.
3Without OpenSSL. Windows ships without it, so the signature and eIDAS steps report that they could not run. Install OpenSSL 3 and run the script again for a full check.
4RESULT. The result is INCOMPLETE only because two checks could not run; everything that ran passed.

Windows PowerShell

1PS C:\Users\you\Downloads\proofsnap_20261015_094107> powershell -ExecutionPolicy Bypass -File verification\verify.ps1

============================================================

ProofSnap Evidence Verification

============================================================

[1/4] File integrity - SHA-256 of every file vs manifest.json

------------------------------------------------------------

2 OK metadata.json

OK page.html

OK screenshot.jpeg

OK evidence.pdf

OK provenance_certificate.pdf

OK domtextcontent.txt

OK c2pa.json

OK page.mhtml

OK forensic_log.json

OK forensic_log_summary.txt

OK verification/verify.sh

OK verification/verify.ps1

OK verification/VERIFICATION_GUIDE.txt

OK chain_of_custody.json

NOT HASHED publickey.pem (listed without a hash, presence only)

NOT HASHED manifest.sig (listed without a hash, presence only)

RESULT: all 14 hashed file(s) match

[2/4] Manifest signature - RSA over manifest.json

------------------------------------------------------------

3 openssl is not installed here, so the signature could not be checked.

Install OpenSSL, or verify online. This says nothing about the package.

[3/4] eIDAS RFC 3161 qualified timestamp

------------------------------------------------------------

openssl is not installed here, so the token could not be read.

To check the token's own signature and its chain to the authority root:

openssl ts -verify -in manifest.json.tsr -data "manifest.json" -CAfile <tsa-root>.pem

Certificate chain + OCSP/CRL are in eidas_validation.json. The root

cert is the 'rootCaPem' field: copy its value into a .pem file and

pass that as -CAfile.

openssl is not installed here, so the command above cannot be run.

Install OpenSSL 3.x, or verify online. The file-integrity check

does not depend on openssl and has already run above.

[4/4] Bitcoin OpenTimestamps anchor

------------------------------------------------------------

manifest.json.ots present. Deep verify (needs the ots client):

ots verify manifest.json.ots -f "manifest.json"

============================================================

4 RESULT: INCOMPLETE - everything that was checked here passed,

but 2 check(s) could not be run for want of a tool. Nothing

above suggests a defect in the package.

============================================================

Simplified Windows PowerShell window on a computer without OpenSSL, which is the Windows default. Lines as verify.ps1 prints them; the folder is an example.

Step 10, without ProofSnap

Or follow VERIFICATION_GUIDE.txt by hand

Experts who prefer to type every command themselves, or who cannot run scripts, find the manual procedure in verification/VERIFICATION_GUIDE.txt. It is part of the signed package, like the scripts.

1Evidence ID. Ties the guide to this package.
2A) The scripts. The commands from steps 8 and 9.
3B) Online. The address of the Trust Verifier, step 7.
4C) By hand. Four steps, each with the exact command.
5Step 1. Recompute each file's SHA-256 and compare it with the manifest.
6Step 2. The openssl command for the manifest signature. Further down: the eIDAS command with notes on OpenSSL 3 versus the LibreSSL that macOS installs under the name openssl, and the OpenTimestamps command.

VERIFICATION_GUIDE.txt

ProofSnap: Evidence Verification Guide

========================================================================

1Evidence ID: ps_7c1e4b2a-93f0-4d5e-b8a1-2f6c0d9e4a37

This package is self-contained. Everything needed to verify it is inside the

ZIP. Three ways to verify:

2 A) Run the bundled script (from the package root)

macOS / Linux: bash verification/verify.sh

Windows: powershell -ExecutionPolicy Bypass -File verification\verify.ps1

3 B) Verify online, drag the ZIP onto https://getproofsnap.com/verify/index.html

4 C) Run the four steps below by hand.

------------------------------------------------------------------------

5STEP 1: File integrity (SHA-256)

------------------------------------------------------------------------

manifest.json lists the SHA-256 hash of every file it covers. Recompute each

hash and compare: any mismatch, or any file listed and absent, means the package

was altered after signing. manifest.sig, publickey.pem, manifest.json.tsr,

manifest.json.ots and eidas_validation.json are produced from the finished

manifest and therefore sit outside it by construction; they are checked in

steps 2, 3 and 4 instead.

macOS/Linux: shasum -a 256 <file>

Windows: Get-FileHash <file> -Algorithm SHA256

------------------------------------------------------------------------

6STEP 2: Manifest signature (RSA + SHA-256)

------------------------------------------------------------------------

manifest.sig is a detached RSA signature over manifest.json, made with the

private key whose public half is publickey.pem. Verify:

openssl dgst -sha256 -verify publickey.pem -signature manifest.sig manifest.json

The start of the guide in a plain text viewer (simplified). It goes on with step 3 (eIDAS), step 4 (OpenTimestamps) and the hash chain. The evidence ID is an example.

How to verify the eIDAS and Bitcoin timestamps by hand

The eIDAS timestamp with OpenSSL

The qualified timestamp of a ProofSnap package is the file manifest.json.tsr.

Copy the value of the rootCaPem field in eidas_validation.json into a file named tsa-root.pem.
Compare it with the published fingerprint of CA Disig QCA4 that verify.sh prints.
From the unzipped folder, run openssl ts -verify -in manifest.json.tsr -data manifest.json -CAfile tsa-root.pem.

Use OpenSSL 3, not the LibreSSL that macOS installs as openssl.

The Bitcoin anchor with the OpenTimestamps client

Install the OpenTimestamps client (ots) and run ots verify manifest.json.ots -f manifest.json. A confirmed proof names the Bitcoin block, which shows that the manifest existed no later than that block. A proof that is still pending needs another run a few hours later.

When the Bitcoin anchor is pending

Verify again a few hours later

A Bitcoin timestamp is final only once a Bitcoin block includes it. Right after a capture the proof is submitted but not yet confirmed. This is normal and does not change the verdict. To check an .ots proof on its own, see how to verify an OpenTimestamps file.

1Pending. Submitted: pending Bitcoin confirmation (typically 1-3 hours). On the website: OpenTimestamps: Proof submitted, pending confirmation.
2Verified. Verify the same, unchanged ZIP again after a few hours: the line now names the Bitcoin block. It shows that the package existed no later than that block. Do not try to update or replace the .ots file.

Minutes after the capture

1

Blockchain Timestamp: Submitted: pending Bitcoin confirmation (typically 1-3 hours). Fully verifiable after confirmation.

A few hours later, same ZIP

2

OpenTimestamps: Verified. Anchored to Bitcoin block 970418, confirming existence as of 2026-10-15 +04 (UTC).

The OpenTimestamps line in the side panel's technical verification. Block number and date are examples.

When the verdict is modified

Do not repair the ZIP: go back to the original

Open Show technical verification: the red line names the check and usually the file. Do not try to fix the package; any change makes it fail again. Verify the original download instead. The most common causes are harmless handling mistakes:

1A file was changed. Opening a file inside the package and saving it, even without visible edits, or renaming it, changes what the manifest vouches for.
2The package was unpacked and zipped again. Re-zipping often puts everything one folder deeper, so the verifier no longer finds manifest.json at the top of the ZIP. Some tools also add their own hidden files.

If the original download also shows modified, keep it as it is and write to support@getproofsnap.com with the red line from the technical verification.

A file inside was opened and saved again

Integrity: modified

Hide technical verification

manifest.json: Signature is valid. The file was signed using the provided public key, and the signature matches the manifest contents.

1

File Integrity: 1 of 16 files FAILED verification (metadata.json).

The package was unpacked and zipped again

Integrity: modified

Hide technical verification

2

Error: Missing required files in zip: manifest.json, manifest.sig, publickey.pem. The zip file may be corrupted or incomplete.

Issuer: this package is signed with a key generated inside the package.

Top of the technical verification in two typical cases. File names are examples.

Common questions

Very large packages, usually long videos, cannot be read whole by a browser. Use verify.sh or verify.ps1 from the package (step 8 or 9): they read the files one by one and have no size limit.

macOS installs LibreSSL under the name openssl. It cannot read an attribute that qualified timestamps carry, so its own ts -verify command reports an error even on a valid timestamp. verify.sh says so and runs its signature check another way. For the full chain, use OpenSSL 3.

Evidence anyone can check

Received a ProofSnap package? Check it in the Trust Verifier. Need to capture your own? Install ProofSnap.

Install ProofSnap, 7 days free

Also available for Microsoft Edge

More guides: How to capture a web page · Long video evidence · How to certify a file · How to read an evidence package

How to verify a ProofSnap evidence package

Three ways to verify

In the ProofSnap side panel

On this website

With the scripts in the ZIP

What a successful verification proves

The three routes compared

Before you start

Work with the original ZIP

Verify in the ProofSnap side panel

Find the ProofSnap Trust Verifier

Upload the ZIP and click Verify zip file

Read the verdict

Open the technical verification

The timestamp lines

Check the original file against the certificate

Verify on the website

Verify on getproofsnap.com, no account needed

Verify without ProofSnap

Run verify.sh on macOS or Linux

Run verify.ps1 on Windows

Or follow VERIFICATION_GUIDE.txt by hand

How to verify the eIDAS and Bitcoin timestamps by hand

The eIDAS timestamp with OpenSSL

The Bitcoin anchor with the OpenTimestamps client

Two results that need a second look

Verify again a few hours later

Do not repair the ZIP: go back to the original

Common questions

Evidence anyone can check