SSHive on iOS is a Swift app from end to end. The terminal is SwiftTerm, a mature xterm-256color emulator written in Swift: it handles VT100 and xterm escape sequences, 256 colors, the alternate screen that less, vim and htop switch to, bracketed paste and mouse reporting. The SSH layer is Citadel, a Swift implementation of SSH2, and every connection checks the server's host key against the fingerprint recorded the first time.
Credentials are Keychain items marked WhenUnlockedThisDeviceOnly. With Require Face ID / Touch ID on, they are also bound to your current biometric enrollment: reading one takes Face ID, Touch ID or the device passcode, and SSHive reuses that single authentication for the whole connection instead of asking twice. An encrypted private key is decrypted on the device with the OpenSSH key format's own derivation, bcrypt-pbkdf.
The network on a phone is not a desk. iOS suspends an app that goes to the background, so a session you leave for long will be cut; a keep-alive, 30 seconds by default, keeps a session you are still using from being dropped by a firewall or NAT that forgets idle connections. When the servers are only reachable behind a gateway, a VPN profile attached to the SSH profile is brought up before the connection.
On iPhone, the key bar is what makes a shell usable: Esc, Tab, Ctrl and Alt are one tap away, so Ctrl+C stops a runaway command and Ctrl+R finds the one you ran yesterday. On iPad, the sidebar keeps your open sessions in view, and a hardware keyboard turns the same app into a comfortable place for longer work.