Remail was written to sidestep the hard-to-solve problem of sending encrypted mail to multiple people, some of whom may prefer to use GnuPG, some PGP from Symantec, while others use S/MIME from coroprate-issued CAs that are not in universal CA trust stores.

Remail accepts both S/MIME and PGP-encrypted email sent to a single address, decrypts it on the back-end, and then recrypts to individual list subscribers using whichever is their preferred scheme for email encryption.