Pronounced CUR-dee-shim.
Crdyshim is a UEFI bootloader intended as an alternative to shim. Its purpose is to load, verify, and run a more complicated bootloader such as crdyboot. Since crdyshim is a first-stage bootloader (meaning it is run directly by the firmware), it will need to be signed by Microsoft for use on most PCs. By keeping crdyshim very simple, we aim to make updates infrequent. This is important so that we don't have to go through the full testing and signing process often.
This bootloader is in the same repo as crdyboot so that they can share code and tests, but they are not inherently tied together other than crdyshim hardcoding the filename of crdyboot.