question: public String toHexString ( byte [ ] block ) { StringBuffer buf = new StringBuffer ( ) ; int len = block . length ; for ( int i = 0 ; i < len ; i ++ ) { bytetohex ( ( byte ) ( block [ i ] + 128 ) , buf ) ; if ( i < len - 1 ) { buf . append ( ":" ) ; } } return buf . toString ( ) ; }
target:  Converts a given byte block to comprehensible hexadecimal String