vb.net - DES Serialization Exception -

i , having trouble deserializing object des cryptography.

i getting exception says "bad data." in deserializedesobjectfromfile function.

can please have working?

here code:

    public sub serializedesobjecttofile(filename string, item object)     dim fs filestream     dim formatter new binaryformatter      dim deskey() byte = {200, 5, 78, 232, 9, 6, 0, 4}     dim desinitializationvector() byte = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}     dim mystreamencrypter cryptostream = nothing      fs = new filestream(filename, filemode.create)     dim desalgorithm des     desalgorithm = new descryptoserviceprovider     mystreamencrypter = new cryptostream(fs, desalgorithm.createencryptor(deskey, desinitializationvector), cryptostreammode.write)      try         formatter.serialize(mystreamencrypter, item)     catch e exception         console.writeline("failed serialize. reason: " & e.message)             fs.close()     end try end sub  public function deserializedesobjectfromfile(filename string) object     dim fs new filestream(filename, filemode.open)     dim itemtoreturn new object      dim deskey() byte = {200, 5, 78, 232, 9, 6, 0, 4}     dim desinitializationvector() byte = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}     dim mystreamdecrypter cryptostream = nothing      dim desalgorithm des     desalgorithm = new descryptoserviceprovider      mystreamdecrypter = new cryptostream(fs, desalgorithm.createdecryptor(deskey, desinitializationvector), cryptostreammode.read)      try         dim formatter new binaryformatter         itemtoreturn = directcast(formatter.deserialize(mystreamdecrypter), object)         return itemtoreturn     catch e exception         msgbox(e.message)         return nothing             fs.close()     end try end function 

it important make sure last block in stream flushed. block ciphers modes such ecb mode , cbc mode need padded because block cipher can encrypt full blocks of plaintext. stream not know serialized data object last data has encrypt, cannot pad , encrypt last block itself.

the flushfinalblock should called after have written last plain text data cryptostream. alternatively call close() on upper cryptostream instead of underlying stream, or make sure disposed before call close() on underlying stream.