The functions included are for generating the base64-encode of a sha1 hash of the input string sent in as an argument.
This is the mechanism for processing something to be used as the header for either the Sec-WebSocket-Key request header or Sec-WebSocket-Accept response header in the websocket opening handshake.
To generate the Sec-WebSocket-Key, you would use generateRandomBase64String; for the matching Sec-WebSocket-Accept header value, you would use base64EncodeOfSha1Hash(keyConcatenatedWithMagicString).