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digitalmars.D.bugs - [Issue 10661] New: Add secureZeroMemory function in Phobos

http://d.puremagic.com/issues/show_bug.cgi?id=10661

           Summary: Add secureZeroMemory function in Phobos
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc


--- Comment #0 from bearophile_hugs eml.cc 2013-07-17 04:30:49 PDT ---
I propose to add to Phobos a function similar to SecureZeroMemory that the D
compiler handles in a special way:

http://msdn.microsoft.com/en-us/library/windows/desktop/aa366877%28v=vs.85%29.aspx

This function acts like a memset, to zero an interval of memory. What's special
of it is that the compiler never optimizes it away. So it's usable in
cryptographic functions that must assure undesired information never exits the
function.


As example usage in std.digest.md, a strongly optimizing D compiler like LDC2
used with link-time optimization can optimize away this zeroing:


struct MD5
{
...
        private nothrow pure void transform(const(ubyte[64])* block)
        {
...
            //Zeroize sensitive information.
            x[] = 0;
        }


That can be replaced by a call to secureZeroMemory() to ensure the desired
safety. Having a standard function in Phobos, supported by the compiler makes
this small feature portable across all D compilers, unlike C++ where
SecureZeroMemory is just a Windows function.

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Jul 17 2013