When you have received your encryption/decoding result, click h key to resume. Only lowercase letters and 32 specific symbols work in this and the only method it allows is atbash. Uppercase letters will be supported in a future update, for now no :(
Update Log: 17.03.22: Version 1.1 - Symbols and digits can be used now! However, a glitch renders some characters as a '9' 16.03.22: Version 1.0 - First release!