Audio files may store tag information separate from the sound itself.
ID3 tags, often used in MP3 files, may contain titles, artist names, album names, creators, comments, images, and information related to recording or editing.
When publishing audio anonymously, even if the voice is processed, anonymity is weakened if the ID3 tags retain a real name, account name, creation environment, or original filename.
This article organizes what ID3 tags are, which information becomes risky, and what to check before publication.
What ID3 tags are
ID3 tags are metadata mainly attached to MP3 files.
Music players show song names, artist names, and album images because this tag information is used.
Tag information
Content
Anonymity caution
Title
Title
Original recording name or content may appear
Artist
Artist name
Real names or account names may remain
Album
Album name
Project names or classifications may remain
Comment
Comment
Editing notes or internal information may remain
Cover Art
Embedded image
Pay attention to information in the image and metadata
Software
Creation or editing software
Becomes a clue about the work environment
Tag information in audio files cannot be fully checked from the playback screen alone.
For that reason, tag information is an area that is easy to miss.
Why ID3 tags relate to anonymity
When publishing audio anonymously, many people pay attention to the voice and content.
However, information also remains in tags inside the file.
For example, a recording app may automatically add a title, editing software may insert a creator name, or different information may be embedded in cover art.
Situation
Information that may remain
Smartphone recording
Recording date and time, app name, original filename
Audio editing software
Creator, project name, software name
Podcast export
Title, author name, program name
Voice memo sharing
Comment, recording name, device information
Audio with cover image
Metadata inside the image and visible information
ID3 tags alone do not necessarily identify the person.
However, when combined with voice, manner of speaking, content, posting time, account, and past audio, they become material for correlation.
ID3 tags and embedded images
Audio files may have cover images embedded in them.
These images also need attention.
The cover image may show a face, logo, place, or creator name. In addition, the image itself may contain metadata.
Embedded image information
Risk
Face photo
The person or related people become identifiable
Logo
Affiliation, organization, or project becomes identifiable
Place
Shooting location or routine places become identifiable
Text
Names, event names, or dates remain
Image metadata
Creation time or editing information may remain
When checking an audio file, look not only at the sound, but also at embedded images.
Even in players that do not visibly display them, images may remain inside the tags.
Check voice and tags separately
Even if ID3 tags are removed, voice and environmental sounds remain.
Conversely, even if the voice is processed, a creator name may remain in tags.
Check target
What to look at
Tag information
Title, creator, comment, image, software name
Voice
Voice quality, way of speaking, dialect, habits
Content
Proper nouns, timeline, places, related people
Environmental sound
Sounds from stations, shops, workplaces, schools, or homes
Filename
Names, dates, places, project or case names
The anonymity of an audio file is not determined only by tag removal.
Check file-internal information, audio content, filename, and posting environment separately.
Pre-publication check
Before publishing an audio file, check in the following order.
Order
Check
Reason
1
Look at ID3 tags
Check whether titles, creators, or comments remain
2
Look at embedded images
Check cover images and image metadata
3
Look at the filename
Check whether it includes a real name, date, or place
4
Listen to the whole audio
Check voice, conversation, and environmental sound
5
Recheck after processing
Check whether deletion or conversion succeeded
Audio contains a lot of information even in short files.
Momentary information can remain, such as someone calling a name in the background, a station name playing, or a notification sound.
Recheck after tag removal
After removing ID3 tags, always recheck.
Depending on the deletion tool or conversion process, only some tags may disappear while other tags remain.
Check
Reason
Whether title and author disappeared
Check direct identifying information
Whether comments remain
Look for editing notes or internal information
Whether embedded images disappeared
Check whether cover images remain
Whether a new creation software name was added
Check post-conversion information
Whether the filename has problems
Avoid leakage through outer information
Audio files may receive new metadata after conversion.
For that reason, include post-processing confirmation in the pre-publication check.
For high-risk audio, do not upload files to online conversion sites or online tag editing sites. Check and process locally as much as possible. External services may receive file content, source IP address, check time, and browser information.
However, tools do not understand the meaning of the audio.
Even if ID3 tags are removed, humans must check clues remaining in the voice and environmental sound.
Consider the publication format for high-risk audio
For high-risk content, deciding not to publish the audio as-is may also be appropriate.
Options include transcribing the voice and publishing only the content, generalizing proper nouns, summarizing without releasing the audio, or asking a trusted person to check it after understanding the sharing risk.
However, even in transcription, clues from writing style and content remain.
Changing the format does not make it safe. What matters is choosing which information to leave.
ID3 tags remain during redistribution too
Audio files may be downloaded and reuploaded somewhere else.
If tags remain in a file once published, they continue to remain in copies even if you delete them yourself later.
Especially for audio that is easy to preserve, such as podcasts, audio materials, recording memos, and activity records, pre-publication checking is important.
Checking tags before publication is more reliable than noticing and deleting them after posting.
Correlation with other information
ID3 tags become stronger when connected with other information.
Combination
What happens
Artist + voice
Tag name and voice create the impression of the same person
Creation time + posting time
Posting immediately after recording is inferred
Comment + content
Editing notes and spoken content connect
Cover image + past image
Connects with another account
Filename + tag
External file information overlaps
In anonymity, do not look at ID3 tags alone.
Check them together with audio content, account, posting time, and past public materials.
Summary
ID3 tags are metadata stored in audio files.
Titles, authors, comments, embedded images, creation software, and similar information may remain.
When publishing audio anonymously, check not only voice and content, but also tag information.
Even if tags are removed, voice, way of speaking, environmental sound, filename, and posting time remain.
For audio files, metadata checks, audio checks, filename checks, and post-processing rechecks should be performed together.
Related tools
Metadata inspection
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.