NullPointerException in EncFSCrypto.mac64()

[mrpdaemon]

Got this backtrace on Google Play Developer Console:

Caused by: java.lang.NullPointerException
at org.mrpdaemon.sec.encfs.EncFSCrypto.mac64(EncFSCrypto.java:327)
at org.mrpdaemon.sec.encfs.EncFSCrypto.mac32(EncFSCrypto.java:348)
at org.mrpdaemon.sec.encfs.EncFSCrypto.mac16(EncFSCrypto.java:360)
at org.mrpdaemon.sec.encfs.BasicFilenameDecryptionStrategy.verifyDecryptionWorked(BasicFilenameDecryptionStrategy.java:78)
at org.mrpdaemon.sec.encfs.BasicFilenameDecryptionStrategy.decryptImpl(BasicFilenameDecryptionStrategy.java:61)
at org.mrpdaemon.sec.encfs.FilenameDecryptionStrategy.decrypt(FilenameDecryptionStrategy.java:51)
at org.mrpdaemon.sec.encfs.EncFSCrypto.decodeName(EncFSCrypto.java:184)
at org.mrpdaemon.sec.encfs.EncFSFile.listFiles(EncFSFile.java:228)