Many operators in perl have a private variable called a "target" that is used to return the result. This is basically a hidden lexical that you can't directly act on. You can try keeping all your sensitive code in coderefs: 
$sensitive_code = eval 'sub {
    my ($foo,$bar,$baz) = @_;
    $sensitive = "D-$foo-$bar-$baz";
    # do stuff with $sensitive
    return;
}';
$sensitive_code->("charanga","Boom","BANG");

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and then undef $sensitive_code; when you want to clean up (followed by a lot of miscellanous code to allocate different sizes of blocks of memory and wipe them). But it's going to be pretty difficult to guarantee success. I'd resort to XS or Inline::C for this.

Update: actually, not sure you need the eval to get/clear a fresh pad.

In reply to Re: making perl more forgetting by ysth
in thread making perl more forgetting by ddzeko

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