AES加密是目前广泛使用的对称加密算法之一，适用于各种密码管理系统。下面是在VB.NET中使用AES加密的示例代码：

1. 引入命名空间

Imports System.Security.Cryptography
Imports System.Text

2. 创建AES加密算法实例

Dim aes As Aes = Aes.Create()

3. 设置加密密钥和初始化向量

加密密钥和初始化向量长度必须与AES算法的块长度相同。一般使用16字节或32字节长度的密钥。在这个示例中，我们使用长度为32字节的密钥和初始化向量。

Dim key As Byte() = Encoding.UTF8.GetBytes("12345678901234567890123456789012")
Dim iv As Byte() = Encoding.UTF8.GetBytes("abcdefghijklmnop")

4. 对明文进行加密

Dim plaintext As Byte() = Encoding.UTF8.GetBytes("the message to encrypt")
Dim encrypted As Byte() = Nothing

Using aesAlg As Aes = Aes.Create()
    aesAlg.Key = key
    aesAlg.IV = iv
    Dim encryptor As ICryptoTransform = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV)
    Using msEncrypt As New IO.MemoryStream()
        Using csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
            csEncrypt.Write(plaintext, 0, plaintext.Length)
            csEncrypt.FlushFinalBlock()
            encrypted = msEncrypt.ToArray()
        End Using
    End Using
End Using

5. 对密文进行解密

Dim encrypted As Byte() = ... ' The encrypted message
Dim plaintext As Byte() = Nothing

Using aesAlg As Aes = Aes.Create()
    aesAlg.Key = key
    aesAlg.IV = iv
    Dim decryptor As ICryptoTransform = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV)
    Using msDecrypt As New IO.MemoryStream(encrypted)
        Using csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)
            Using msReader As New IO.MemoryStream()
                Dim buffer(8192) As Byte
                Dim bytesRead As Integer
                bytesRead = csDecrypt.Read(buffer, 0, buffer.Length)
                While bytesRead > 0
                    msReader.Write(buffer, 0, bytesRead)
                    bytesRead = csDecrypt.Read(buffer, 0, buffer.Length)
                End While