ProtectedMemory.Protect Method (Byte(), MemoryProtectionScope)


Protects the specified data.

Namespace:   System.Security.Cryptography
Assembly:  System.Security (in System.Security.dll)

Public Shared Sub Protect (
	userData As Byte(),
	scope As MemoryProtectionScope


Type: System.Byte()

The byte array containing data in memory to protect. The array must be a multiple of 16 bytes.

Type: System.Security.Cryptography.MemoryProtectionScope

One of the enumeration values that specifies the scope of memory protection.

Exception Condition

userData must be 16 bytes in length or in multiples of 16 bytes.


The operating system does not support this method. This method can be used only with the Windows 2000 or later operating systems.


userData is null.

This method can be used to protect data in memory. Note that the method does not make a copy of the data, but encrypts the byte array in place. The userData parameter must be 16 bytes in length or a multiple of 16 bytes.

Support for this method is available in the Windows XP and later operating systems.

The following code example shows how to use data protection.

Imports System
Imports System.Security.Cryptography

Public Class MemoryProtectionSample

    Public Shared Sub Main()
        ' Create the original data to be encrypted (The data length should be a multiple of 16).
        Dim secret As Byte() = {1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4}

        ' Encrypt the data in memory. The result is stored in the same same array as the original data.
        ProtectedMemory.Protect(secret, MemoryProtectionScope.SameLogon)

        ' Decrypt the data in memory and store in the original array.
        ProtectedMemory.Unprotect(secret, MemoryProtectionScope.SameLogon)

    End Sub
End Class

.NET Framework
Available since 2.0
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