如何通过VB.NET使用存储在web.config中的密钥对字段进行加密？

Imports System.Configuration
Imports System.Security.Cryptography
Imports System.Text

Public Class EncryptionHelper
    Public Shared Function EncryptData(data As String) As String
        Dim config As Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)
        Dim section As AppSettingsSection = DirectCast(config.GetSection("appSettings"), AppSettingsSection)
        Dim key As String = section.Settings("EncryptionKey").Value

        Dim provider As New AesCryptoServiceProvider()
        provider.Key = Encoding.ASCII.GetBytes(key)
        provider.Mode = CipherMode.ECB
        provider.Padding = PaddingMode.PKCS7

        Dim encryptor As ICryptoTransform = provider.CreateEncryptor()

        Dim dataBytes As Byte() = Encoding.ASCII.GetBytes(data)
        Dim encryptedDataBytes As Byte() = encryptor.TransformFinalBlock(dataBytes, 0, dataBytes.Length)

        Return Convert.ToBase64String(encryptedDataBytes)
    End Function

    Public Shared Function DecryptData(encryptedData As String) As String
        Dim config As Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)
        Dim section As AppSettingsSection = DirectCast(config.GetSection("appSettings"), AppSettingsSection)
        Dim key As String = section.Settings("EncryptionKey").Value

        Dim provider As New AesCryptoServiceProvider()
        provider.Key = Encoding.ASCII.GetBytes(key)
        provider.Mode = CipherMode.ECB
        provider.Padding = PaddingMode.PKCS7

        Dim decryptor As ICryptoTransform = provider.CreateDecryptor()

        Dim encryptedDataBytes As Byte() = Convert.FromBase64String(encryptedData)
        Dim decryptedDataBytes As Byte() = decryptor.TransformFinalBlock(encryptedDataBytes, 0, encryptedDataBytes.Length)

        Return Encoding.ASCII.GetString(decryptedDataBytes)
    End Function
End Class

<configuration>
  <appSettings>
    <add key="EncryptionKey" value="your_encryption_key_here" />
  </appSettings>
</configuration>