如何使用 SecureString 创建 SHA1 或 SHA512 哈希？

Question

我想在 VB.NET 中使用 SecureString 变量并将其转换为 SHA1 或 SHA512 哈希。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使用的 String 实例（输出）并将其替换为字符数组，那又如何呢？这将使我们能够在使用后擦除这个数组：

    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;
    }

有什么我错过的吗？