CharToInt converts a character [a~zA~Z0~9] into a integer [0, 61].

F is a function that takes a key and data, and generates a hash F does not have to be inverseable.

MakeHash is a helper function that generates a 36-bit unsigned random integer.

GenerateWord24 id the same as GenerateWord36, except it takes a 24 bit integer and produces a wid with 2 words.

GenerateWord36 takes a 36 bit unsigned integer and converts it to a wid with 3 words.

MakeHash is a helper function that takes a 120 bit id (20 char) and makes a 36 bit id Make sure the char is UTF-8.

Swap36 swaps the lower and upper 18 bits of the data.

structure for Encrypter.