empty variable

[JB]

Hi Tom,

Thanks for the fast reply & info!

That was an interesting link.  Here are a
few lines from the link,

----------
The delete variable command not only removes the contents of the variable, but deletes it entirely from memory. If you delete a key from an array variable, that element of the array no longer exists as part of the variable.

Local variables that are used within a handler are automatically deleted when the handler in which they are used exits.

You can't delete local or global variables, using delete you just put the value empty in them.
----------

So it sounds to me from the last line above that putting empty into the variable is secure.

JB


> On Jan 3, 2020, at 10:55 AM, Tom Glod via use-livecode <use-livecode at lists.runrev.com> wrote:
> 
> A memory dump can reveal everything stored in memory for a particular
> process.
> 
> the delete variable command is what you are looking for.
> 
> https://livecode.fandom.com/wiki/Delete_variable
> 
> 
> 
> On Fri, Jan 3, 2020 at 1:22 PM JB via use-livecode <
> use-livecode at lists.runrev.com> wrote:
> 
>> What if I have secure info like a password stored
>> in a local variable and then I clear that info by
>> putting empty into that local variable.
>> 
>> How secure is that procedure?  I understand a
>> local variable does not retain the info after the
>> code finishes but I am concerned about any
>> info left in memory.
>> 
>> In the c language to clear the memory you set
>> all of the blocks to null.  That is because it is
>> more secure than doing something like putting
>> empty into the variable.
>> 
>> So the question is when I put empty into a local
>> variable I know when you access that variable it
>> will return empty but if it has not been set to null
>> then is it possible for someone to read the blocks
>> of memory and get anything back.  In c if you set
>> all of the blocks to null and not just the first block
>> then you have eliminated the chance of someone
>> recovering the info.  Is there a secure way to clear
>> a variable in Livecode?
>> 
>> JB
>> 
>> 
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> 
> 
> -- 
> Tom Glod
> Founder & Developer
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