question: private byte [ ] padPassword ( byte [ ] password ) { if ( password == null ) { password = new byte [ 0 ] ; } byte [ ] padded = new byte [ 32 ] ; final int numContributingPasswordBytes = password . length > padded . length ? padded . length : password . length ; System . arraycopy ( password , 0 , padded , 0 , numContributingPasswordBytes ) ; if ( password . length < padded . length ) { System . arraycopy ( PW_PADDING , 0 , padded , password . length , padded . length - password . length ) ; } return padded ; }
target:  Pad a password as per step 1 of Algorithm 3.2 of the PDF Reference version 1.7