I finnally understood the secret of 10g, 11g wrapped PLSQL, after serveral days working. It also support 9i, now! Base on it, I worked out a little tool to unwrap the 9i, 10g, 11g PLSQL code. Here is full version.
Usage：
Input User, Password and TNSNAME -> Connect to 9i, 10g、11g database server -> choose schema, code type -> choose the code ->Unwrap
OR
Input the wrapped code into the wrap text editor directly(10g, 11g only)->Unwrap
Size: 1,302K
Type: ZIP
Language: English