ProtectedData.Protect Method (Byte(), Byte(), DataProtectionScope)
Encrypts the data in a specified byte array and returns a byte array that contains the encrypted data.
Assembly: System.Security (in System.Security.dll)
Public Shared Function Protect ( userData As Byte(), optionalEntropy As Byte(), scope As DataProtectionScope ) As Byte()
Parameters
- userData
-
Type:
System.Byte()
A byte array that contains data to encrypt.
- optionalEntropy
-
Type:
System.Byte()
An optional additional byte array used to increase the complexity of the encryption, or null for no additional complexity.
- scope
-
Type:
System.Security.Cryptography.DataProtectionScope
One of the enumeration values that specifies the scope of encryption.
| Exception | Condition |
|---|---|
| ArgumentNullException | The userData parameter is null. |
| CryptographicException | The encryption failed. |
| NotSupportedException | The operating system does not support this method. |
| OutOfMemoryException | The system ran out of memory while encrypting the data. |
This method can be used to encrypt data such as passwords, keys, or connection strings. The optionalEntropy parameter enables you to add data to increase the complexity of the encryption; specify null for no additional complexity. If provided, this information must also be used when decrypting the data using the Unprotect method.
Note |
|---|
If you use this method during impersonation, you may receive the following error: "Key not valid for use in specified state." To prevent this error, load the profile of the user you want to impersonate before calling the method. |
The following example shows how to use data protection.
Imports System Imports System.Security.Cryptography Public Class DataProtectionSample ' Create byte array for additional entropy when using Protect method. Private Shared s_aditionalEntropy As Byte() = {9, 8, 7, 6, 5} Public Shared Sub Main() ' Create a simple byte array containing data to be encrypted. Dim secret As Byte() = {0, 1, 2, 3, 4, 1, 2, 3, 4} 'Encrypt the data. Dim encryptedSecret As Byte() = Protect(secret) Console.WriteLine("The encrypted byte array is:") PrintValues(encryptedSecret) ' Decrypt the data and store in a byte array. Dim originalData As Byte() = Unprotect(encryptedSecret) Console.WriteLine("{0}The original data is:", Environment.NewLine) PrintValues(originalData) End Sub Public Shared Function Protect(ByVal data() As Byte) As Byte() Try ' Encrypt the data using DataProtectionScope.CurrentUser. The result can be decrypted ' only by the same current user. Return ProtectedData.Protect(data, s_aditionalEntropy, DataProtectionScope.CurrentUser) Catch e As CryptographicException Console.WriteLine("Data was not encrypted. An error occurred.") Console.WriteLine(e.ToString()) Return Nothing End Try End Function Public Shared Function Unprotect(ByVal data() As Byte) As Byte() Try 'Decrypt the data using DataProtectionScope.CurrentUser. Return ProtectedData.Unprotect(data, s_aditionalEntropy, DataProtectionScope.CurrentUser) Catch e As CryptographicException Console.WriteLine("Data was not decrypted. An error occurred.") Console.WriteLine(e.ToString()) Return Nothing End Try End Function Public Shared Sub PrintValues(ByVal myArr() As [Byte]) Dim i As [Byte] For Each i In myArr Console.Write(vbTab + "{0}", i) Next i Console.WriteLine() End Sub End Class
with the associated ProtectData flag for permission to protect data.
Available since 2.0
