Capability to search content of ProtonMail messages currently seems to depend on storage of the messages on a local drive, in plaintext form. A PM user could locate the messages storage location, manually encrypt that directory, and then decrypt it when a detailed message search is required, remembering to encrypt again upon completion of the search operations. But this seems like tedious work that could be automated. Perhaps an interface could be built between the ProtonMail search function and encryption software, so that the user would only have to enter a password, or otherwise authenticate the use of encryption software, before the search would be conducted. Upon completion of the search, the PM user would have the option of again encrypting the locally stored messages, or performing additional content searches on the plaintext.