Author Information in Documents, PDFs, and Office Files
Documents, PDFs, and Office files may retain author information, edit history, comments, file paths, annotations, hidden data, and evidence-related clues.
When handling documents for whistleblowing, do not look only at the body text.
PDFs, Word, Excel, PowerPoint, and imaged materials may retain author information, edit history, comments, templates, file paths, and distribution identifiers.
Even if you remove a name from the body text, anonymity breaks if the author's name remains inside the file.
This article organizes author information in documents, PDFs, and Office files that requires particular caution in whistleblowing.
What Is Author Information?
Author information is information attached to a file, such as the author, company name, editor, creation software, and creation date/time.
Office documents and PDFs may retain information that is not visible from the document's appearance.
| Information | What it shows |
|---|---|
| Author name | Real name or internal account name |
| Company name | Affiliated organization |
| Last modified by | Person involved in editing |
| Creation date/time | When the material was created |
| File path | Department name, user name, device name |
| Comments | Internal conversations or responsible people's names |
These may remain as properties or metadata even if they do not appear on the screen when the file is opened.
Cautions for Office Files
Word, Excel, and PowerPoint easily retain change history and comments.
Especially in internal documents, reviewers, department names, revision history, hidden sheets, and embedded objects become clues.
| Office file information | Risk |
|---|---|
| Change history | Shows who edited which part |
| Comments | Responsible people's names and internal conversations remain |
| Hidden sheets | Data not visible on the surface remains |
| Embedded files | Original materials or separate files are included |
| Template | Organization name or department name is visible |
Sending Office files outside as-is is dangerous.
Create a publication copy and check for unnecessary history and comments. However, in situations where evidentiary value is needed, preserve the original before processing.
Cautions for PDFs
PDFs look safe, but information remains inside them.
They may include author, creation software, annotations, forms, embedded text, text under redaction, and attached files.
| PDF information | Caution |
|---|---|
| Author | Real name or organization name remains |
| Annotations | Comments and review history are visible |
| Embedded text | Text under redaction may remain |
| Forms | Input history or field names remain |
| Attached files | Separate files may be included inside the PDF |
Simply converting to PDF does not make a file safe.
Check redaction, annotations, properties, and embedded information.
Be Careful With Redaction Failures
In whistleblowing materials, names or numbers may be redacted.
However, if you only place a black rectangle on top, the text underneath may remain. It may be possible to copy text from the PDF, search for it, or see it when layers are removed.
| Redaction failure | What happens |
|---|---|
| Only placing a shape over text | Original text appears through copying or search |
| Only hiding with an annotation | It becomes visible when annotations are hidden |
| Insufficient imaging | Text can be read at high resolution |
| Removing only part of it | It is inferred from surrounding information |
| Including the original file | Unprocessed materials remain |
Do not judge redaction by appearance alone.
Open the publication file in another app, and check copying, search, and properties.
Limits of Screenshots
Some people think making a screenshot of a document makes it safe.
Screenshots may reduce some metadata, but they are not a universal solution. Notifications, account names, times, OS UI, browser tabs, and filenames may appear on the screen. Image files may also retain creation time or device information.
| What remains in screenshots | Caution |
|---|---|
| Notifications | Real-name accounts or other services appear |
| Browser tabs | Pages or services being viewed are visible |
| Time | Connects with behavior history |
| Filename | Case names or department names are visible |
| Image metadata | Creation time or device information may remain |
Converting to a screenshot is not a process that removes all problems from the original.
It requires separate checking as a publication image.
Separate Checking From Preservation
In whistleblowing, thinking only about removing metadata is dangerous.
The evidentiary value of the original may matter. Information about when a material was created, who created it, and its authenticity may be needed.
| File | Handling |
|---|---|
| Original | Store safely to preserve evidentiary value |
| Checking copy | Inspect metadata and content |
| Submission copy | Match the recipient-side procedure |
| Publication copy | Remove unnecessary personal information |
What to remove and what to keep changes depending on the purpose.
Providing information to a news organization, consulting a lawyer, and public posting require different judgments.
Do Not Judge by Tools Alone
Metadata checking tools are useful.
ExifTool is a representative tool used to check metadata in many file formats.
URL : https://exiftool.org/
However, information visible to tools is not the only risk. Internal terminology in the body text, document numbers, distribution scope, phrasing habits, and the small number of people who could obtain the file also narrow candidates.
Follow the Recipient's Procedure
It is also important not to over-process whistleblowing materials by your own judgment.
News organizations, lawyers, support groups, and reporting desks may each have procedures for receiving materials and policies for evidence preservation. Before submission, check what format to send, whether the original is needed, and whether an anonymized copy is acceptable.
| Recipient | What to check |
|---|---|
| News organization | Anonymous submission channel and material format |
| Lawyer | Original preservation, evidentiary value, whether processing is allowed |
| Support group | Safe consultation route, necessary materials |
| Internal reporting desk | Identity verification, logs, retaliation risk |
| Administrative agency | Submission format, procedure, handling of identity information |
Safe document handling changes depending on the purpose and destination.
Do not decide by yourself that "deleting makes it safe." Check both the necessary evidentiary value and anonymity.
If judgment is difficult, confirm a safe way to consult the recipient before submission.
Document handling is work that deals with anonymity and evidentiary value at the same time.
If only one side is prioritized, risks that cannot be explained later remain.
Summary
Documents, PDFs, and Office files may retain author information, edit history, comments, file paths, annotations, and hidden data.
Even if you remove a name from the body text, anonymity breaks if a real name or organization name remains inside the file.
In whistleblowing, separate originals, checking copies, submission copies, and publication copies. For materials where evidentiary value is needed, do not process them carelessly; check with a specialist or recipient.
Metadata checking tools are useful, but content correlation and distribution-scope correlation also need to be checked at the same time.
Related tools
ExifTool
An external resource related to this article. Open it only when it fits your situation and threat model.
Why it is listed: It can help with the article topic, but it is outside Anonymity Sense and should be checked before use.
URL : https://exiftool.org/
MAT2
An external resource related to this article. Open it only when it fits your situation and threat model.
Why it is listed: It can help with the article topic, but it is outside Anonymity Sense and should be checked before use.
qpdf
An external resource related to this article. Open it only when it fits your situation and threat model.
Why it is listed: It can help with the article topic, but it is outside Anonymity Sense and should be checked before use.
SecureDrop
An external resource related to this article. Open it only when it fits your situation and threat model.
Why it is listed: It can help with the article topic, but it is outside Anonymity Sense and should be checked before use.
URL : https://securedrop.org/
GlobaLeaks
An external resource related to this article. Open it only when it fits your situation and threat model.
Why it is listed: It can help with the article topic, but it is outside Anonymity Sense and should be checked before use.
URL : https://globaleaks.org/