RapidCRC is an open source CRC, MD5, and SHA hashing program. It supports to allow writing of Unicode .sfv, .md5, .sha1, .sha256, and .sha512 files which can be turned on or off through the settings page. Unicode sfv files are written as UTF-16LE with BOM or UTF-8 (with or without BOM), and RCRC now performs a codepage detection. The shell extension that was included in the source code enables all operations directly from the extension. Features include multithreaded hash calculations with asynchronous I/O, ed2k hash calculation, SHA hash calculation, job queuing, and popup menu to copy the calculated hashes to the clipboard.