How to Report a Modified PDF to the Sender: A Professional Guide

Discovering that a PDF document you received has been modified can be unsettling. Whether it is an invoice, contract, certificate, or payment confirmation, document tampering raises serious concerns about authenticity and trust.

But here is the important thing: a "modified" result does not automatically mean fraud. Many legitimate actions create modifications — re-saving a file, adding digital signatures, converting formats, or making authorized edits. The key is knowing how to communicate professionally and gather more information.

This guide will help you navigate this sensitive situation while maintaining professional relationships.

Understanding HTPBE's Confidence Levels

Before reaching out to anyone, it is crucial to understand what this analysis actually tells you:

100% Confidence (Definitive Finding)

When HTPBE shows 100% Confidence, it means the analysis has found conclusive cryptographic evidence that the PDF was modified after its digital signature was applied. This is a definitive finding — it cannot be a false positive.

This happens when:

• A digitally signed PDF was edited after signing
• The signature hash no longer matches the document content
• There are modifications detected after the signature timestamp

High Confidence

High Confidence indicates strong structural evidence that the PDF was modified after its initial creation. While highly reliable, false positives can occur in some legitimate workflows:

• Linearized PDFs (optimized for web viewing)
• PDF/A conversion for archival
• Re-saving without content changes
• Form field filling

Standard Detection

For files without digital signatures, HTPBE's analysis examines metadata, cross-reference tables, incremental updates, and other technical indicators. These provide strong evidence but should be considered alongside the document context.

Step 1: Share the Result

The easiest way to start a conversation is to share your HTPBE result directly with the sender. Every result page has a Share button that generates a shareable link.

When you share a result:

• The recipient sees the exact same analysis you see
• They can review all technical details themselves
• No accusations needed — just "here is what I found"
• The conversation starts from a neutral, factual basis

Sample Message with Shared Result

Hi [Name],

I was reviewing the [document type] you sent on [date] as part of my standard verification process. I used htpbe.tech to check the PDF, and it flagged some concerns I wanted to discuss with you.

Here is the analysis report: [paste HTPBE result link]

Could you help me understand if any modifications were made to this document before sending? I want to make sure we are working with the correct version.

Thanks for your help!

[Your Name]

This approach is:

• Non-accusatory — you are asking for clarification, not making accusations
• Transparent — they see exactly what you see
• Professional — you are following a verification process, not singling them out

Step 2: Understanding Their Response

If They Confirm Legitimate Modification

Many modifications are perfectly normal:

If their explanation makes sense:

• Request documentation of the changes if needed for records
• Ask for the original version if your compliance requires it
• Update your verification records accordingly

If They Are Unaware of Modifications

This is a red flag that requires escalation:

1. Request a fresh copy directly from their source system (not email)
2. Verify through an alternative channel — call them directly using a known number
3. Check for email compromise — fraudsters often intercept emails and modify attachments
4. Document everything — keep records of all communication

Warning: Invoice fraud often involves intercepting legitimate emails and changing payment details. If an invoice shows unexpected bank account changes along with modification markers, treat this as a serious security incident.

If They Do Not Respond

• Send a follow-up after 48–72 hours
• Use an alternative contact method (phone call, different email)
• Document all communication attempts
• Do not proceed with payments or actions based on unverified documents

Step 3: When You Disagree with the Result

What if you believe this analysis is incorrect? HTPBE has a Dispute This Result feature specifically for this situation.

How the Dispute Process Works

1. Click "Dispute This Result" on any result page
2. Optionally provide your email for follow-up
3. Submit the dispute

What happens next:

• The HTPBE team receives the analysis metadata (filename, scores, technical indicators)
• They manually review the file using advanced forensic techniques
• If they find the analysis was incorrect, they update the result
• If you provided an email, they contact you with their findings

Privacy note: We only receive metadata — your actual PDF content is never transmitted during a dispute.

When to Use Dispute

Use the dispute feature when:

• You know the document is original but it shows as modified
• The sender confirms no modifications were made
• You have additional context HTPBE might not have considered
• The analysis seems inconsistent with the document source

Professional Email Templates

Template 1: Initial Inquiry (Neutral Tone)

Subject: Document Verification Request — [Document Name/Reference]

Dear [Name],

I hope this message finds you well. I am writing regarding the [document type] you sent on [date].

As part of my standard document verification process, I ran the file through htpbe.tech. The analysis detected some indicators that suggest the file may have been modified after its original creation.

You can view the full analysis here: [HTPBE Result Link]

This is not necessarily a concern — many legitimate actions like adding signatures or converting formats can trigger these indicators. However, I wanted to reach out to confirm:

1. Were any modifications made to this document before sending?
2. Could you verify that this is the correct and final version?
3. If available, could you provide the document directly from your source system?

I appreciate your understanding and cooperation.

Best regards, [Your Name]

Template 2: Follow-Up (After No Response)

Subject: Follow-Up: Document Verification — [Document Name/Reference]

Dear [Name],

I am following up on my previous message from [date] regarding the [document type].

The verification process flagged some concerns that I need to resolve before we can proceed. You can review the analysis here: [HTPBE Result Link]

Could you please respond at your earliest convenience? If I do not hear back by [date], I will need to [escalate to your supervisor / delay processing / use alternative verification methods].

Thank you for your prompt attention to this matter.

Best regards, [Your Name]

Template 3: Escalation (Serious Concerns)

Subject: URGENT: Document Authentication Required — [Document Name/Reference]

Dear [Name/Department],

I am escalating a document verification issue that requires immediate attention.

The [document type] dated [date] has been flagged by htpbe.tech with high-confidence modification indicators. You can view the technical analysis here: [HTPBE Result Link]

Given the nature of this document [describe importance — e.g., "which includes payment instructions for $X"], I need to verify its authenticity before proceeding.

Please:

1. Confirm whether this document was intentionally modified
2. Provide the original, unmodified version if available
3. Verify the payment/banking details through an independent channel

I am available at [phone number] if you prefer to discuss this directly.

Regards, [Your Name] [Your Position]

Best Practices for Document Security

To minimize issues with modified documents in the future:

1. Always verify important documents — make PDF verification part of your standard workflow
2. Request digitally signed PDFs — signatures provide cryptographic proof of authenticity
3. Establish verification protocols with regular partners and vendors
4. Use secure channels for document exchange (encrypted email, secure portals)
5. Verify payment changes through phone calls to known numbers, never through email alone
6. Keep records of all verification results for audit purposes

When to Involve Security or Legal Teams

Consider escalating to your security, compliance, or legal team if:

• The document involves significant financial transactions
• Modifications appear to alter critical information (amounts, dates, account numbers, terms)
• The sender cannot or will not explain the modifications
• You suspect intentional fraud or document tampering
• The document is part of a legal or regulatory matter

HTPBE as Your Neutral Arbiter

If you and the document sender cannot agree on whether a file has been modified, HTPBE can serve as a neutral third party:

1. Both parties review the same HTPBE result
2. Either party can submit a dispute for manual review
3. Our forensic team provides an independent assessment
4. The result serves as objective evidence for both sides

This is particularly useful in:

• Vendor disputes about invoice authenticity
• Contract disagreements about document versions
• Insurance claims requiring document verification
• Legal matters where document integrity is questioned

Conclusion

Discovering a modified PDF does not automatically mean fraud or wrongdoing. Many modifications are innocent and explainable. The key is approaching the situation professionally:

1. Share the result — let the other party see what you see
2. Ask questions — give them a chance to explain
3. Document everything — keep records of all communication
4. Escalate when needed — do not proceed with unverified critical documents
5. Use the dispute process — let us help when you need a neutral assessment

By following these steps, you protect yourself and your organization while maintaining professional relationships and trust.

Verify any PDF before sharing concerns — Free analysis at HTPBE