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C# SecureString Question

Is there any way to get the value of a SecureString without comprising security? For example, in the code below as soon as you do PtrToStringBSTR the string is no longer secure because strings are immutable and garbage collection is non-deterministic for strings. 

IntPtr ptr = Marshal.SecureStringToBSTR(SecureString object);
string value = Marshal.PtrToStringBSTR(ptr);

What if there were a way to get a char[] or byte[] of the unmanaged BSTR string? Would that mean garbage collection is more predictable (since you would be using a char[] or byte[] rather than a string? Is this assumption correct, and if so, how would you get back the char[] or byte[]?

Solution

  • This should help you: Marshaling SecureString Passwords to String

    From the article, the key points are:

    • Pin the string in memory.
    • Use managed pointers to mutate the System.String.
    • Use the strong guarantees of the ExecuteCodeWithGuaranteedCleanup method.