Wednesday, January 8, 2020

Search inside S/MIME messages

Since V0.1.16 Fossa Guard Pro extension supports multi-language search inside S/MIME encrypted messages using a locally built full-text index which contains words statistics and does not contain the content of the messages.
You can download the index to ensure this fact - it has Elasticlunr format and stores statistics on email's subject, body and attachments` names.
Firstly, the user should decide what languages he would like to use for searching to use specific stemming and stopwords filtering from the following list:

  • English (default)
  • German
  • French
  • Spanish
  • Italian
  • Dutch
  • Danish
  • Portuguese
  • Finnish
  • Romanian
  • Hungarian
  • Russian
  • Norwegian
  • Swedish
  • Turkish

where English is the default language.
Please keep in mind that each additional language support slows down a bit indexing and searching.

Click `Build Search Index` to start the indexing all emails in all folders labeled by S/MIME label. Fossa Guard Pro tries automatically label all new incoming S/MIME emails basing on email's content type but anyway please make sure you have all emails planned for searching labeled.
User can be requested to confirm languages selection in case he has chosen more than 2 additional languages:

Once the confirmation received the index build will be started indicating the number of emails processed out of total S/MIME emails discovered.

Note that during the process User will be requested to enter the passphrase for the private key access to decoded S/MIME encrypted message. The passphrase will be cached for 10 minutes to make the indexing process convenient for the User

Once the index will be built it keeps the time of the last update to incrementally refresh the index in the future.

Index metadata contains also the language selection, the number of emails indexed and approximate size of the index. For the moment the index is stored in the local storage of the extension which is limited by 5 megabytes.
The User can

  • `Download` the index in JSON format (lately ability to import the index will appear which can be helpful for some special cases 
  • `Refresh` the index when all new emails since the time of last update will be checked on S/MIME content type and will be added to the index.
  • `Remove` the index 

To search indexed emails the User should use standard Gmail search bar with the `smime:` prefix:

The drop-down list should display a scrollable list of all matched emails so that the User points it and open in one click.

That's all about search in S/MIME emails implemented in Fossa Guard Pro version.
Happy New Year!