Verifying a Signed Export

It is possible to digitally sign an export of archived messages to the file system when as EML or MSG format is used. This helps to ensure integrity of each exported email while it resides outside of the archive. A SHA256 hash of the public key, that can be used to verify the signatures, is stored in the archive's temper proof audit log.

In order to verify the integrity of a signed export, the OpenSSL executable may be used. This needs to be installed on the computer where verification takes place.

Create Hash of Public Key

The following command generates a SHA256 hash of the public key in order to verify it against the hash recorded in MailStore's Audit Log.

  openssl dgst -sha256 -hex publickey.pem

Verify All Emails

The following one-liners can be used to verify a signed export including all subdirectories.

Linux or MacOS

  find . -name '*.eml' -exec openssl dgst -sha256 -verify publickey.pem -signature \{}.sig \{} \;

Windows (PowerShell)

  ls -r *.eml | ForEach-Object { $file_sig = ($_.FullName) + '.sig';  $file_eml = $_.FullName; openssl.exe dgst -sha256 -verify publickey.pem -signature  "$file_sig" "$file_eml" }