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P2P Secure File, Encrypt and Decrypt Any File with Password

, 5 Apr 2008 CPOL
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Protect any file by encryption and decryption with password. It encrypts the file and saves as secure XML with binary format, and stores file password as custom PK encrypter routine.



This article discusses how you can protect any file by encrypting with password. Download the source code of P2P Secure File written in VB.NET. It encrypts the file and saves it as secure XML with binary format, and stores file password as custom PK encrypter routine.


This P2P Secure File program source code written in Visual Basic .NET programming language is capable of encrypting and decrypting any file. It converts any file into byte array and converts byte array to stream and writes it into XML file with *.sp2p extension.

Using the Code


Step 1: First select a file. Convert the file content into Byte array. For that, we create FileStream object and pass this FileStream object to BinaryReader to get the raw bytes.

 Dim Fs As New System.IO.FileStream(FileName, System.IO.FileMode.Open)
 Dim bn As New System.IO.BinaryReader(Fs) 

Step 2: Now create a DataTable to a DataSet to store all the details including file name, binary content and encrypted password.

Dim DsImg As New DataSet
Dim Dt As New DataTable("Images")
Dt.Columns.Add(New DataColumn("sysid", _
Dt.Columns.Add(New DataColumn("filename", _
Dt.Columns.Add(New DataColumn("image", _
Dt.Columns.Add(New DataColumn("filetag", _

Step 3: Now add the data to the DataTable and write XML file with *.sp2p extension, encrypt password with custom PK encryption. If you want, you can encrypt the binary content. I left this to the users.

Dim Dr As DataRow
Dr = DsImg.Tables("images").NewRow
Dr("sysid") = Now.ToString
Dr("filename") = TxtFileName.Text
Dr("image") = bn.ReadBytes(Int(bn.BaseStream.Length))
Dr("filetag") = StrEncrypt(TxtPassword.Text)

'>>> write xml file from dataset with binary content
DsImg.WriteXml(TxtFileName.Text & ".sp2p") 

Step 4: For decryption, we load the XML file into dataset, then decrypt the password to check with the supplied password, If it matches, read content from dataset into byte array and write into the file stream, remove .sp2p from the final decrypted file.

Dim Content As Byte()
Content = DsImg.Tables(0).Rows(0).Item(2)
Dim Fs As New System.IO.FileStream(FileName, System.IO.FileMode.Create)
Fs.Write(Content, 0, Content.Length)

Points of Interest

Here I write a chunk of bytes to file system directly. If you want, you can encrypt or transpose the byte sequence for better security. You can find a more detailed explanation of encryption algorithm on my site programmer2programmer.


  • 5th April, 2008: Initial post


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Atanu Maity
CEO Programmer2Programmer
India India
Master in Computer Application
More than 8 Years of Software Developer Experience. MCSD.Net, In past 8 years I have developed Graphic Application, Telephony Application, CRM Application, Games, Internet Programming, TAPI, SAPI, OCR, ICR, Data Base application. Implementing Data Warehousing and Data mining, MIS Automation, Web Application.

Comments and Discussions

GeneralMy vote of 5 PinmemberShubhranshu from Mumba1-Apr-12 20:28 
GeneralMy vote of 4 PinmemberMember 432084415-Aug-11 2:13 
Questionwhat algorithm this project use? PinmemberNURFAEZAH ABDUL MALIK19-Oct-10 6:01 
Generalblowing my own horn a bit sorry PinmemberMartyK20074-Jun-08 1:42 
Hey in my article[^]

in my examples there is an example of encrypting and decrypting files in a seperate thread , delivered to the thread by a queue system, but using standed .NET components to do the encryption/decryption.

you can drill into the example and find that code and use it without the queuing system and multi threading.

It may help

life is a bowl of cherries
go on take a byte

Generalsorry, this code does not encrypt any files, it encrypts the specified password only PinmemberAlexey Yakovlev9-Apr-08 7:55 
GeneralRe: sorry, this code does not encrypt any files, it encrypts the specified password only PinmemberAtanu Maity9-Apr-08 19:56 
GeneralRe: sorry, this code does not encrypt any files, it encrypts the specified password only PinmemberAlexey Yakovlev11-Apr-08 6:50 
GeneralRe: sorry, this code does not encrypt any files, it encrypts the specified password only PinmemberAtanu Maity11-Apr-08 22:12 
GeneralAwesome Pinmembersuresh suthar9-Apr-08 4:18 
GeneralRe: Awesome PinmemberAbhijit Jana10-May-08 2:43 
GeneralThank You PinmemberprabhaChoudhary7-Apr-08 21:35 
GeneralRe: Thank You PinmemberAtanu Maity8-Apr-08 22:52 
Questionthank you Pinmemberalaa masarweh7-Apr-08 6:16 
GeneralRe: thank you PinmemberAtanu Maity7-Apr-08 8:10 
GeneralToo good... PinmemberSushilck7-Apr-08 4:11 
AnswerRe: Too good... PinmemberAtanu Maity7-Apr-08 4:34 
QuestionWant to encrypt text file? PinmemberJoy_Dass19817-Apr-08 4:06 
AnswerRe: Want to encrypt text file? PinmemberAtanu Maity7-Apr-08 4:32 
GeneralNice Algorithm PinmemberSapana IR6-Apr-08 20:19 
GeneralRe: Nice Algorithm PinmemberAtanu Maity6-Apr-08 20:24 
Questionlarge file issue? PinmemberDankarmy6-Apr-08 11:01 
AnswerRe: large file issue? PinmemberAtanu Maity6-Apr-08 20:10 
GeneralRe: large file issue? PinmemberDankarmy7-Apr-08 13:29 

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