Search attachments by Hash #198

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MrUnknownDE · 2026-04-05T16:17:00+02:00

MrUnknownDE commented

2026-04-05 16:17:00 +02:00

Originally created by @piotrmkaminski on 9/24/2025

Is your feature request related to a problem? Please describe.
When archiving emails (or other messages) with attachments, it can be very helpful to later find conversations by the attachment rather than just the email text. For example, if I have a copy of a file I once sent, I’d like to search by its hash (or a fingerprint) and find which conversation(s) included that file. This is especially useful for forensic, auditing, or eDiscovery use cases.

Describe the solution you'd like

Compute and store cryptographic hashes (e.g. SHA-256) for each attachment.

Archive attachments in full or deduplicated by hash, linking identical files across multiple emails.

Provide a search interface (UI/API) that allows lookup by attachment hash, filename, or metadata and returns the associated conversations.

Support integrity verification by checking stored attachments against their hashes.

Describe alternatives you've considered

Relying on filename-based search, which is unreliable as filenames can be changed.

Searching only in the body of emails, which does not cover cases where the needed information resides solely in attachments.

Additional context
Use cases:

A user has a file on disk and wants to check if it was ever sent; by computing the hash, they can find all related messages.

During legal discovery, it should be possible to trace where a particular document has been shared.

Deduplication reduces storage needs by keeping one copy of identical attachments.

Auditing is improved by verifying that stored attachments remain unchanged (integrity checks).

*Originally created by @piotrmkaminski on 9/24/2025* Is your feature request related to a problem? Please describe. When archiving emails (or other messages) with attachments, it can be very helpful to later find conversations by the attachment rather than just the email text. For example, if I have a copy of a file I once sent, I’d like to search by its hash (or a fingerprint) and find which conversation(s) included that file. This is especially useful for forensic, auditing, or eDiscovery use cases. Describe the solution you'd like Compute and store cryptographic hashes (e.g. SHA-256) for each attachment. Archive attachments in full or deduplicated by hash, linking identical files across multiple emails. Provide a search interface (UI/API) that allows lookup by attachment hash, filename, or metadata and returns the associated conversations. Support integrity verification by checking stored attachments against their hashes. Describe alternatives you've considered Relying on filename-based search, which is unreliable as filenames can be changed. Searching only in the body of emails, which does not cover cases where the needed information resides solely in attachments. Additional context Use cases: A user has a file on disk and wants to check if it was ever sent; by computing the hash, they can find all related messages. During legal discovery, it should be possible to trace where a particular document has been shared. Deduplication reduces storage needs by keeping one copy of identical attachments. Auditing is improved by verifying that stored attachments remain unchanged (integrity checks).

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Reference: github/OpenArchiver#198