One little nitpick: the checksum error probability should be more like 9 nines. The checksum contains 4 bytes, not 4 bits, and so the false positive rate shoul

One little nitpick: the checksum error probability should be more like 9 nines. The checksum contains 4 bytes, not 4 bits, and so the false positive rate should be about 1 in 2^32, not 1 in 2^4. "The raw 25 bytes of our address though contain 1 byte for a Version (the Bitcoin “main net” is b'\x00', while the Bitcoin “test net” uses b'\x6f'), then the 20 bytes from the hash digest, and finally 4 bytes for a checksum so we can throw an error with 1 - 1/2*4 = 93.75% probability in case a user messes up typing in their Bitcoin address into some textbox."