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How to check is a SecureString object is empty

I need to use the SecureString in my C# web application. However in looking at this class I don't see of a way to determine if a SecureString object is empty. If I know that the the String class has an IsNullOrEmpty(String) method however, SecureString does not. Does someone know of a way to determine in a SecureString object is an empty string?

https://msdn.microsoft.com/en-us/library/system.security.securestring(v=vs.110).aspx

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Fernando Soto

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Mlanda T

https://msdn.microsoft.com/en-us/library/system.security.securestring.length(v=vs.110).aspx

Use the length property

Fernando Soto

@MlandaT, I think that is what I stated in my post.

Brady Kelly

But what about whitespace? i don't know, but surely SecureString can contain non-visible characters, such as a NewLine or something.

Fernando Soto

Hi Brady;

From Microsoft documentation

The SecureString class has no members that inspect, compare, or convert the value of a SecureString. The absence of such members helps protect the value of the instance from accidental or malicious exposure. Use appropriate members of the System.Runtime.InteropServices.Marshal class, such as the SecureStringToBSTR method, to manipulate the value of a SecureString object.

If you have any questions on this post please post a new question.

Thanks

Brady Kelly

I accept that the only way to check if a SecureString is truly empty is by its Length property, but my first comment was more a rhetorical question, to warn the OP that Length == 0 is not a safe replacement for IsNullOrEmpty, although he should be using IsNullOrWhiteSpace. The following code shows the length of a practically useless SecureString to be correct: 10, but ten 0 chars is as good as empty, or at least would not pass IsNullOrWhiteSpace if it were a normal string:

    SecureString badPwd = new SecureString();
    for (var i = 0; i < 10; i++)
    {
        badPwd.AppendChar((char)0);
    }
    var badlen = badPwd.Length;
    var check = string.IsNullOrWhiteSpace(new string((char)0, 10));

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badlen == 10, and check = false.