I want to clear up something important for everyone in this Puzzle journey.

The truth is: prefixes (whether in Base58 addresses or HASH160) have no relation to the actual private key. Through many experiments step by step till now, I can confirm that once we pass through the irreversible transformation of elliptic curve multiplication, any hope of tracing back from a prefix to the real private key is gone. 

Thinking that a certain prefix gives us a “hint” about the actual key is just wishful thinking.

The only practical use of prefixes is to measure and track our scanning progress. For example:

Base58 (addresses):

Each character = 1 in 58 chance. 
Probability of matching n chars = 1 / 58ⁿ. 

In 2³² ≈ 4.29B scans you expect: 

1 char ≈ 74M matches 
2 chars ≈ 1M matches 
3 chars ≈ 22K matches 
4 chars ≈ 376 matches 
5 chars ≈ 7 matches 
6 chars ≈ 1 matches 

HASH160 (hex):

Each hex digit = 1 in 16 chance. 
Probability of matching n digits = 1 / 16ⁿ. 

In 2³² ≈ 4.29B scans you expect: 

1 char ≈ 268M matches 
2 chars ≈ 17M matches 
3 chars ≈ 1M matches 
4 chars ≈ 67k matches 
5 chars ≈ 4k matches 
6 chars ≈ 268 matches 
7 chars ≈ 16 matches 
8 chars ≈ 1 matches 

(On my one RTX 3060 Ti, this 2³² scan finishes in ~2 seconds, and I typically get 1 or 2 addresses with an 8-chars initial HASH160 hex match - sometimes none at all.) 

This shows clearly: prefix matching is only a statistical milestone, or a POW, not a clue toward the target private key.

Regarding fixed bits - my own “fixed bits” formula based on prefix matching is still random - it doesn’t inject any new logic or shortcut.

So in the end, prefix-based searching is just for fun, to keep ourselves engaged while facing the massive challenge of scanning through a 2^71 keyspace.

This puzzle is all about grinding through the natural variance of randomness until we get lucky. That’s the true nature of brute force.