Windows Phone encrypts and decrypts files

 Private   Void Decryption ( String  Mima) {isolatedstoragefilestream = New Isolatedstoragefilestream ( "  Aaa.zip Encryption  " , Filemode. Open, fileaccess. read, This  . Storgfile); isolatedstoragefilestream stream2 = New Isolatedstoragefilestream ( " Aaa.zip  " + "  Decryption  " , Filemode. openorcreate, fileaccess. Write, This  . Storgfile );  Byte [] Buffer = New   Byte [ 100  ];  Long Num = 0l  ; Long Length = Stream. length;  String Password = Mima;  String S = "  Saltvalue  "  ;  Byte [] Salt = Encoding. utf8.getbytes (s); rfc2898derivebytes bytes = New  Rfc2898derivebytes (password, salt ); This . AES. keysize = This . AES. legalkeysizes [ 0  ]. Maxsize;  This . AES. blocksize = This . AES. legalblocksizes [ 0  ]. Maxsize;  This . AES. Key = bytes. getbytes ( This . AES. keysize/ 8  );  This . AES. IV = bytes. getbytes (This . AES. blocksize/ 8  ); Cryptostream stream3 = New Cryptostream (stream2, This . AES. createdecryptor ( This . AES. Key, This  . AES. IV), cryptostreammode. Write );  Try  {  Try  {  While (Num < Length ){  Int Count = stream. Read (buffer, 0 , 100  ); Stream3.write (buffer,  0  , Count); num + = Count;} stream3.close ();}  Catch  {MessageBox. Show (  " Incorrect password! Cannot decrypt!  "  );}}  Finally  {Stream. Close (); stream2.close ();}} 

  Private   Void Encryption ( String  Mima ){  //  Try  {Isolatedstoragefilestream stream = New Isolatedstoragefilestream ( "  Aaa.zip  " , Filemode. Open, fileaccess. read, This  . Storgfile); isolatedstoragefilestream stream2 = New Isolatedstoragefilestream ( "  Aaa.zip  " + "  Encryption  " , Filemode. openorcreate, fileaccess. Write, This . Storgfile );  Byte [] Buffer = New   Byte [ 100  ];  Long Num = 0l  ;  Long Length = Stream. length;  String Password = Mima;  String S ="  Saltvalue  "  ;  Byte [] Salt = Encoding. utf8.getbytes (s); rfc2898derivebytes bytes = New  Rfc2898derivebytes (password, salt );  This . AES. keysize = This . AES. legalkeysizes [ 0  ]. Maxsize;  This . AES. blocksize =This . AES. legalblocksizes [ 0  ]. Maxsize;  This . AES. Key = bytes. getbytes ( This . AES. keysize/ 8  );  This . AES. IV = bytes. getbytes ( This . AES. blocksize/ 8  ); Cryptostream stream3 = New Cryptostream (stream2,This . AES. createencryptor ( This . AES. Key, This  . AES. IV), cryptostreammode. Write );  While (Num < Length ){  Int Count = stream. Read (buffer, 0 , 100  ); Stream3.write (buffer,  0  , Count); num + =Count;} MessageBox. Show (  "  File encrypted!  "  ); Stream3.close (); stream. Close (); stream2.close ();}  //  Catch  //  {  //  MessageBox. Show ("the file is not placed in the specified isolatedstore directory! ");  //  } }