A cryptocurrency is, most simply, a digital asset. It is called a currency because it was created to work as a medium of exchange in the same way that we use fiat currencies now.
Wavelets are wavelike functions used to transform signals into a representation which has time and frequency domain components. Visually wavelets appear as wave-like oscillations with an amplitude that starts at zero, increases, then returns to zero. Another way to consider a wavelet is as a bandpass filter, which can be applied to a time series under investigation, letting through only components of the time series within a finite range of frequencies to different extents depending on the energy spectrum of the wavelet. Wavelets take the form:

It has a shorter blockchain creation time (one minute) and a vastly greater number of coins in circulation — the creators’ target of 100 billion units mined by July 2015 was met, and there’s a supply limit of 5.2 billion units mined every year thereafter, with no known supply limit.
Whereas in the original SADF test the starting value of the window, r1, was fixed to 0, in the GSADF test the starting point can now vary from 0 to r2 − r0 (this is the last possible starting point, near the end of the data set, that allows the test to be run on the minimum window size).