Survey of PKZIP versions for MS-DOS

I wanted to know exactly what versions of the old PKZIP compression software were publicly released for MS-DOS, and some basic characteristics about them, particularly what compression methods they used when compressing files. Sure, Wikipedia has a list, but it wasn't quite what I wanted, and it omitted at least one version I was pretty … Continue reading Survey of PKZIP versions for MS-DOS

Will the real PKZ110.EXE please stand up?

I've been researching the version history of PKZIP, the once-popular compression software that gave us the still-popular ZIP file format. There are two important MS-DOS versions of it: v1.10, released in March 1990, which was the latest official version for more than 2.5 years, until v2.04c(?) was released in December 1992.v2.04g, released February 1993, which … Continue reading Will the real PKZ110.EXE please stand up?

The 2019 TLS certificate serial number mess

Remember the Great TLS Certificate Serial Number Brouhaha of March, 2019? Millions of website certificates have been mis-issued! Everything is insecure! The sky is falling! Revoke and replace, ASAP! I barely do, but I remember thinking it was a really stupid overreaction. Now I've gone back and reviewed what happened, and I'll try to explain … Continue reading The 2019 TLS certificate serial number mess

Win32 I/O character encoding part 2: chcp 65001

In a previous post, I summarized the character encodings used by Windows console mode programs. This is a short post about a not-very-good mitigation technique for some of the resulting problems. In a future post, I'll go over some better solutions. Sometimes on an internet forum, someone will complain about a third-party Windows console program … Continue reading Win32 I/O character encoding part 2: chcp 65001

Examining the SHA-1 collision files

SHA-1 is a cryptographic hash function. You give it a computer file, and it produces a 160-bit hash that is completely determined by the input file, but not in any obvious way. In early 2017, a group of researchers, using advanced mathematics and 6500 CPU-years of computer searching, found the first ever SHA-1 collision: two … Continue reading Examining the SHA-1 collision files

Summary of some Win32 I/O character encoding behavior

This post is about programming a Windows Win32 application, mainly one that uses the console (command line). It summarizes the results of some tests I performed. Maybe you ported a Unix utility to Windows, but you find that it doesn't work with filenames that contain Japanese characters. This information may help, though specific recommendations will … Continue reading Summary of some Win32 I/O character encoding behavior