Visual Basic

Re: How can I encrypt a string before I add it to file? [modified]

15-Mar-07 12:55

Hello!

I would like to know how to encrypt a string before I add it to database? I should be able to decyrpt it when reading back from database.

Any sample or direction is appreciated.

Thank You. Sigh | :sigh:

What a curious mind needs to discover knowledge is noting else than a pin-hole.

nlarson1115-Mar-07 14:59

nlarson11

15-Mar-07 14:59

I use this method: change the 2 constants to whatever you want

Imports System.Text
Imports System.Security.Cryptography

Public Class Encryption
#Region "Public Routines"
const ENCRYPT_KEY AS STRING = "TEST"
const ENCRYPT_VECTOR AS STRING = "CODEPRJT"

Public Shared Function ToBase64(ByVal sDataToEncrypt As String) As String
Dim stream As System.IO.MemoryStream = New System.IO.MemoryStream
Dim key As Byte() = Encoding.Default.GetBytes(ENCRYPT_KEY.PadRight(24, Chr(0)))
Dim Vector As Byte() = Encoding.Default.GetBytes(ENCRYPT_VECTOR.PadRight(8, Chr(0)))

Dim des As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider
Dim cryptoStream As CryptoStream = New CryptoStream(stream, des.CreateEncryptor(key, Vector), CryptoStreamMode.Write)

Dim Input() As Byte = Encoding.Default.GetBytes(sDataToEncrypt)

cryptoStream.Write(Input, 0, Input.Length)
cryptoStream.FlushFinalBlock()

Return Convert.ToBase64String(stream.ToArray())
End Function

Public Shared Function ToBase32(ByVal sDataToDecrypt As String) As String
Dim stream As System.IO.MemoryStream = New System.IO.MemoryStream
Dim key As Byte() = Encoding.Default.GetBytes(ENCRYPT_KEY.PadRight(24, Chr(0)))
Dim Vector As Byte() = Encoding.Default.GetBytes(ENCRYPT_VECTOR.PadRight(8, Chr(0)))

Dim des As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider
Dim cryptoStream As CryptoStream = New CryptoStream(stream, des.CreateDecryptor(key, Vector), CryptoStreamMode.Write)

Dim Input() As Byte = Convert.FromBase64String(sDataToDecrypt)

cryptoStream.Write(Input, 0, Input.Length)
cryptoStream.FlushFinalBlock()

Return Encoding.Default.GetString(stream.ToArray())
End Function
#End Region
End Class

-- modified at 22:28 Thursday 15th March, 2007

Re: How can I encrypt a string before I add it to file?

JUNEYT16-Mar-07 0:14

Re: How can I encrypt a string before I add it to file?

16-Mar-07 0:14

Thank you vey much I really appreciate it.

What a curious mind needs to discover knowledge is noting else than a pin-hole.

JUNEYT16-Mar-07 2:16

Re: How can I encrypt a string before I add it to file?

16-Mar-07 2:16

Sorry for bothering you but when I used your class, I started getting an error message

Specified key is a known weak key for 'TripleDES' and cannot be used."}

.

I changed these two constants

const ENCRYPT_KEY AS STRING = "NEMESIS"
    const ENCRYPT_VECTOR AS STRING = "DOMAIN"

What is causing the problem?

Thank You. D'Oh! | :doh:

What a curious mind needs to discover knowledge is noting else than a pin-hole.

nlarson1116-Mar-07 3:55

nlarson11

16-Mar-07 3:55

i think it's saying that "domain" is word that shouldn't be used because it's like reserved word. try "dom.ain"

you have upto 24 characters for the key and 8 characters for the vector. my key has period, underscores, dashes, etc in it.

Re: How can I encrypt a string before I add it to file?

JUNEYT16-Mar-07 4:26

Re: How can I encrypt a string before I add it to file?

16-Mar-07 4:26

Thanks for replying but it is giving me the same error message even I use another keyword and vector values...

What a curious mind needs to discover knowledge is noting else than a pin-hole.

nlarson1116-Mar-07 4:35

nlarson11

16-Mar-07 4:35

i think it follows the rules of "complex password" where just letters are not enough

ex of one of my apps:

Const EncryptKey As String = "THE_XXXX_APPLICATION"
Const EncryptVector As String = "X.X.X.X."

takes it fine...

taDataview to datatable?

cstrader23215-Mar-07 11:20

15-Mar-07 11:20

How do I move the rows of a dataview into a datatable?

thanks!

Dave Kreskowiak15-Mar-07 12:44

15-Mar-07 12:44

You don't. A DataView has no rows of its own. A View is just that, a different view of rows in a DataTable.

Dave Kreskowiak
Microsoft MVP - Visual Basic

cstrader23215-Mar-07 13:36

15-Mar-07 13:36

OK, I see. What if I let the user sort a datagrid that is bound to a datatable... how do I get the sorted rows back into the datatable?

thanks again

Dave Kreskowiak15-Mar-07 15:26

15-Mar-07 15:26

You don't. SQL and Access doesn't sort the data in the tables. Sorting only applies to the view of the data, not the table behind it.

When you bind a DataGrid to a DataTable, you're actually seeing the DefaultDataView of that DataTable, not the DataTable itself.

Dave Kreskowiak
Microsoft MVP - Visual Basic

cstrader23216-Mar-07 1:47

16-Mar-07 1:47

OK, but what if I want to allow the user to save the current datagridview as a datatable? How do I get the updated rows of the current view from the datagrid into a new table for saving?

thanks

Dave Kreskowiak16-Mar-07 2:37

16-Mar-07 2:37

It's already a DataTable. The DataGridView is showing you a VIEW of that data, not the data itself.

What are you trying to do with all this?

Dave Kreskowiak
Microsoft MVP - Visual Basic

cstrader23216-Mar-07 3:24

16-Mar-07 3:24

I want to save the edited view as a datatable to xml.

For instance:
1. Read table from XML
2. Put table into datagridview
3. User deletes rows and/or sorts the datagridview
4. User now XMLsaves the edited datagridview as the original datatable

Dave Kreskowiak16-Mar-07 7:05

16-Mar-07 7:05

Since none of these data methods actually saves, or cares, about the order of records, what's the point? The order of the records, as displayed, is controlled by the presentation layer, not the data layer...

Dave Kreskowiak
Microsoft MVP - Visual Basic

cstrader23216-Mar-07 7:13

16-Mar-07 7:13

Right, but I want to persist the modified datatable across sessions in the saved .xml -- or for import to another program.

Dave Kreskowiak16-Mar-07 7:35

16-Mar-07 7:35

You can get a new DataTable made with the current view by calling the .ToTable() method on the view that your DataGridView is bound to. Something like:

Dim newTable As DataTable = myOldTable.DefaultView.ToTable()

You can then save the new table as an XML file using any method you want.

Dave Kreskowiak
Microsoft MVP - Visual Basic

cstrader23216-Mar-07 8:20