Audit Receipts for AI Sanitization: Locally Verifiable SHA-256 Evidence
Document what was sanitized without storing prompts. Each receipt carries SHA-256 digests of the final text and the token labels, and anyone can recompute them offline.
AI Summary / Key Takeaways
"Export a PSR-2 sanitization receipt with SHA-256 digests of the final text, then verify it offline in your browser. Not a digital signature or legal attestation."
Enterprise-Grade AI Privacy
Add custom redaction rules and priority support with PRO.
How to Get and Verify a Receipt
Three steps
Sanitize your text
Paste a prompt or drop a file into PrivacyScrubber and run the scrub. Processing stays in browser memory.
Export the receipt
Click Audit Receipt, then download the official PDF or the TXT log. The TXT log is the file the verifier reads.
Verify it locally
Drop the TXT log into the verifier on this page and paste the final text. A match reports Receipt intact, text matches.
What a PSR-2 Receipt Records, and What It Does Not
A receipt documents one sanitization run. It stores SHA-256 digests, token labels and counts, never the original values. The sample below is built from synthetic text, and its digests are real: load it into the verifier further down to confirm the checksum and the output match yourself.
PRIVACYSCRUBBER ZERO-TRUST DATA SANITIZATION RECEIPT
Illustrative sample (synthetic data)
----------------------------------------------------------------
Receipt Version: PSR-2
Timestamp (UTC): 2026-10-12T12:00:00.000Z
Output SHA-256: ecc2ba29bfe8aeec798c0bd0ebc7883e6b6b9d774d5045697abb288995889e13
Token Manifest SHA-256: e310781f09681166939808c4c9c926d28966b051c28051057bf435503df0bf54
Entity Counts: EMAIL=1,NAME=1,PHONE=1
Tokens In Final Output: 3 of 3 (0 restored or edited out)
Canonical: PSR-2|2026-10-12T12:00:00.000Z|ecc2ba29bfe8aeec798c0bd0ebc7883e6b6b9d774d5045697abb288995889e13|e310781f09681166939808c4c9c926d28966b051c28051057bf435503df0bf54|EMAIL=1,NAME=1,PHONE=1|3/3
Receipt SHA-256: 165f57af0c4a9a2c3757e5878233e00f3b5608b9c43e7c178a72265f5ca6d08e
----------------------------------------------------------------
Measured: output digest, token manifest digest, entity counts, tokens present in the final text.
By design (not measured): the engine runs locally and does not transmit prompt content.
Limits: not a digital signature; does not prove who generated it or when; pattern-based detection
can miss indirect identifiers; not a legal determination of compliance.Measured
- Output SHA-256: digest of the exact final text.
- Token Manifest SHA-256: digest of the sorted token labels. Original values are never hashed or exported.
- Entity counts and how many tokens are still present in the final text.
- Receipt SHA-256: digest of the canonical field line, so edits to the receipt are detectable.
True by design, not measured
- The engine runs in browser memory and does not transmit prompt content. The receipt does not measure network traffic.
- Token-to-original mappings live in volatile session memory. The receipt never records their contents.
What it does not prove
- It is not a digital signature. It does not prove who generated it or when.
- Detection is pattern-based. Indirect identifiers in free text can remain, so review the output before sharing.
- Regulatory references are informational technical-safeguard mappings, not a legal determination of compliance.
Verify a PSR-2 Receipt in Your Browser
Load a PrivacyScrubber receipt (.txt) to recompute its checksum locally. Optionally add the final sanitized text to check it against the receipt's Output SHA-256. Everything runs in browser memory via the Web Cryptography API; nothing is uploaded. This confirms the receipt was not edited and that the text matches it. It does not prove who created the receipt or when.
Which Receipt You Get on Each Plan
The verifier on this page is free for everyone and needs no account. Exporting an official receipt from your own sessions requires PRO or TEAMS; the free tier exports a watermarked sample so you can inspect the format first.
| Capability | Free | PRO | TEAMS |
|---|---|---|---|
| Local receipt verifier (this page) | Yes | Yes | Yes |
| Watermarked sample receipt (illustrative values) | Yes | Yes | Yes |
| Official PDF and TXT log from your own session | No | Yes | Yes |
| Organization name in receipt header and file name | No | Yes | Yes |
PRO is $15/mo or $110 lifetime. TEAMS is $99/mo flat. Compare plans
Using a Receipt as Supporting Evidence
Reviewers asking how sensitive data was handled before an AI tool received it can be given a receipt instead of raw prompts. It is one supporting artifact. Whether it is sufficient is a decision for you and your auditor.
File the receipt with the text
Attach the TXT log and the exact final text to the ticket, pull request or change record. The pair is what makes the digest checkable later.
Reference it in the control narrative
Cite the receipt as evidence of a technical safeguard you describe, such as GDPR Art. 32, SOC 2 CC6.7 or ISO 27001 A.8.11. The mapping is informational.
Re-verify at any time
Load the receipt and the stored text into the verifier. Any edit to the receipt, or to a single character of the text, changes the result to Not verified.
Receipt vs. Prompt Logging vs. Manual Attestation
Three common ways to document how AI inputs were handled, and what each one leaves behind.
| Factor | Raw prompt logging | Manual attestation | PSR-2 receipt |
|---|---|---|---|
| Stores the original sensitive text | Yes, in a log store you must also protect | No | No. Digests, token labels and counts only |
| Edits are detectable | Depends on the logging system | No | Yes, via the receipt checksum and the output digest |
| Anyone can re-check it independently | Needs access to the log system | No | Yes, offline in the verifier on this page |
| Proves who created it and when | Depends on log provenance | No | No. Not a signature; the timestamp is self-reported |
Check the Local-Processing Claim Yourself in 60 Seconds
The receipt cannot measure network traffic, so verify that part directly. Any reviewer can do this with the browser developer tools.
- Open the Network tab. In Chrome or Edge press F12, switch to Network and tick Preserve log.
- Go offline. Pick Offline in the throttling menu, or disconnect Wi-Fi or Ethernet.
- Sanitize and export. Paste sample data into the workspace, run the scrub, then open Audit Receipt.
- Read the log. No request carrying your text should appear. The Network log is the evidence for transmission; the receipt is the evidence for the output.
Frequently Asked Questions
Technical Details & Privacy Architecture
Does a receipt contain my original text?
What does the checksum actually prove?
Is the receipt a digital signature?
Can I use a receipt as evidence in a SOC 2 or ISO 27001 audit?
Which regulatory references does it include?
What is the difference between Free and PRO or TEAMS?
How are the digests calculated?
Can the receipt show that no data left my device?
Document Your Next Sanitization Run
Free exports a watermarked sample. PRO and TEAMS export the official PDF and a TXT log you can verify offline.
