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limited to: Microsoft Macro Assembler (MASM), MS-DOS, Visual C++, Visual Basic,
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Microsoft Portable Executable and COFF (32-bit and 64-bit) Format
Microsoft's proprietary PE checksum algorithm was originally public information.
The IMAGEHLP.DLL source from the NT 3.51 SDK from June 1995 was one of the last known public releases of the algorithm.
Microsoft subsequently made IMAGEHLP.DLL closed-source once it became a standard component of the
NT 4.0 operating system - first released on July 31st, 1996.
The source code has been removed since the August 1996 release of Win32 SDK for Windows 95 and NT 4.0.
As of Windows 10, the Windows loader still uses the same algorithm.