I've just uninstalled #K9Mail and #termux and removed my mobile SSH keys from all of my servers. I do trust the applications on my phone and, to some extent, the OS itself (I've put a lot of work into locking it down) but there will always be vulnerabilities in Android and people to take advantage of them. I don't want to run the risk of leaking the personal info of people who've sent me emails and I certainly don't want to leak SSH keys with access to everything.