I'm using boxcryptor on iPhone 4S with ios 6.0.1
If I create a new source directory in 128aes, then I can't log in this directory.
The window asking for password keep prompting.
Actually I have same issue with aes192, only aes256 works.
Note that it looks like the whole options of the new source directory seem to be messed up because sometime there's a message saying that file name encryption is not supported whereas this option is not activated.