Perhaps I'm missing something obvious, but why can't the filename be encrypted as well?

(So you have public key 0xDEAFBEEF; you want to write a file named 'secret.txt' with the contents 'We attack at dawn'. OweFS encrypts 'We attack at dawn' to 010101 and writes that to 'secret.txt'. But why couldn't it have encrypted the contents to 010101 and encrypted the filename 'secret.txt' to 111000, and then written a file named 111000.encrypted with the contents 010101? Then when the owner of 0xDEAFBEEF wanted to read it, he simply decrypts 111000.encrypted to 'secret.txt' and decrypts its content 010101 to 'We attack at dawn.')