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

How is a JPEG image’s color type determined?

In order to decode and display a JPEG image, you have to know what “color type” (or “color model”) it uses. There are several possibilities that your software probably ought to handle: Grayscale YCbCr (transformed from RGB) RGB YCCK (transformed from CMYK) CMYK Unfortunately, if you look at all the bits and bytes that make…… Continue reading How is a JPEG image’s color type determined?