Question

我想在VB.NET中使用SecureString变量并将其转换为SHA1或SHA512哈希。我如何安全地将SecureString转换为HashAlgorithm.ComputeHash将接受的Byte数组？

Answer 1

如果我们避免使用唯一的String实例（输出）并将其替换为字符数组，那该怎么办呢？这将使我们能够在使用后擦除此数组：

    public static String SecureStringToMD5( SecureString password )
    {
        int passwordLength = password.Length;
        char[] passwordChars = new char[passwordLength];

        // Copy the password from SecureString to our char array
        IntPtr passwortPointer = Marshal.SecureStringToBSTR( password );
        Marshal.Copy( passwortPointer, passwordChars, 0, passwordLength );
        Marshal.ZeroFreeBSTR( passwortPointer );

        // Hash the char array
        MD5 md5Hasher = MD5.Create();
        byte[] hashedPasswordBytes = md5Hasher.ComputeHash( Encoding.Default.GetBytes( passwordChars ) );

        // Wipe the character array from memory
        for (int i = 0; i < passwordChars.Length; i++)
        {
            passwordChars[i] = '\0';
        }

        // Your implementation of representing the hash in a readable manner
        String hashString = ConvertToHexString( hashedPasswordBytes );

        // Return the result
        return hashString;
    }

我错过了什么吗？

Answer 2

在c＃中输入并转换为VB。希望它仍然有用！

Dim input As [Char]() = "Super Secret String".ToCharArray()
Dim secret As New SecureString()

For idx As Integer = 0 To input.Length - 1
    secret.AppendChar(input(idx))
Next
SecurePassword.MakeReadOnly()

Dim pBStr As IntPtr = Marshal.SecureStringToBSTR(secret)

Dim output As String = Marshal.PtrToStringBSTR(pBStr)
Marshal.FreeBSTR(pBStr)

Dim sha As SHA512 = New SHA512Managed()
Dim result As Byte() = sha.ComputeHash(Encoding.UTF8.GetBytes(output))

修改：

正如我和其他几位评论中所指出的那样，我想在此引起关注。这样做不是一个好主意。您正在将字节移动到不再安全的位置。当然你可以做到，但你可能不应该

如何使用SecureString创建SHA1或SHA512哈希？

2 个答案: