I'm pretty amateur on cryptography, and this is cool and everything for basic security, but for those more in the know does the fact that the algorithm knows a

I'm pretty amateur on cryptography, and this is cool and everything for basic security, but for those more in the know does the fact that the algorithm knows a password is "wrong" weaken the cryptography (I realise it's a cool feature of this app, I'm talking generally)? Presumably you would have to test each decrypted result for language words etc. otherwise to know if you had decrypted it correctly.