http://www.stunnel.org/
Stunnel is an SSL wrapper or proxy which can encrypt any TCP traffic on Unix / Linux and Windows. It can be used to encrypt any TCP transaction (http, smtp, pop3, imap, etc).
https://support.mozilla.org/en-US/questions/786035#answer-142961
How to get an SSL client certificate into Firefox on Android. Copy cert9.db and key4.db from phone's SD card Androiddataorg.mozilla.firefoxfilesmozillaprofile.default to dir. Then `pk12util -i file.p12 -d sql:dir`