Re: Using NSValueTransformer for encryption

FROM : Michael Varlik
DATE : Fri Jan 11 07:47:42 2008

-------- Original-Nachricht --------
> Datum: Thu, 10 Jan 2008 14:27:03 -0700
> Von: Keary Suska <<email_removed>>
> An: Michael Varlik <M.<email_removed>>, "Cocoa-Dev (Apple)" <<email_removed>>
> Betreff: Re: Using NSValueTransformer for encryption


> on 1/10/08 1:29 PM, M.<email_removed> purportedly said:
>
> > Consider the following example: The user edits a text whose stringValue
> > shall be encrypted. After endEditing the value is passed to the managed
> > object which stores it. This is where the value transformer comes into
> play.
> > It takes the value from the text field, encrypts it and passes the
> encrypted
> > value to the managed object.
>
> The transformer will work, you'll just need to make sure the "encrypted"
> state of he text is guaranteed from the perspective of the transformer. If
> the value is only stored and maintained in the model in an encrypted form,
> and only edited by the UI, then so you probably won't have problems with
> using a transformer.
>
> > After that, the string value of the text field has to be set to an empty
> > string which sould remove the unencrypted value from memory.
>
> This will not guarantee, in any way, that the value will truly be removed
> >from memory. Just so you know.
>

Hi Keary,

what's the reason for that? Is there a new NSString object created when I
modify a NSTextField's stringValue?

Best regards,
Michael

> Best,
>
> Keary Suska
> Esoteritech, Inc.
> "Demystifying technology for your home or business"
>
>
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