My favorite has been Panic's Prompt. https://www.panic.com/prompt/ https://www.panic.com/prompt/ I find the UI to be very polished. I admit that on iOS I tend

My favorite has been Panic's Prompt. https://www.panic.com/prompt/ https://www.panic.com/prompt/ I find the UI to be very polished. I admit that on iOS I tend to use SSH more from my iPhone than the iPad, and have not really given the other SSH clients a fair test on the iPad. I trust the app with my private keys. I base this trust on the fact that Panic is a very long time and well regarded Mac OS developer. Additionally, I have used their Mac OS Transmit app for SFTP since the original release (I think that is over 15 years ago). Obviously your requirements for trusting an app with your private keys maybe stricter, and require the ability to inspect the code. However if you are at all able to use a closed source app, I feel comfortable to recommend Prompt.