Password generation is flawed

[giucal]

Password generation uses modulo reduction, which notoriously does not preserve uniformity of the random source.

MiniKeePass/MiniKeePass/Password Generator View/PasswordGeneratorViewController.swift

Line 102 in 9b42e00

let idx = Int((cryptoRandomStream?.getInt())! % UInt32(charSet.characters.count))

See the documentation for the SystemRandomNumberGenerator. Something like

Int.random(in: 0..<charsetSize)

does generate cryptographically secure indices in the desired range, which is all that you need.

If you really want to use a Salsa20 key stream, you must implement proper uniform generation. To this end, have a look at the source of next(upperBound:).