The leading bit while in the byte (also the main bit in the very first nibble) is flipped to generate 00000111, which happens to be 0x07, as demonstrated in the reduced sample. append "1" bit to message< // Discover: the input bytes are considered as bit strings, // in which https://sunwin18405.webbuzzfeed.com/34083465/the-best-side-of-what-is-md5-technology