Hi,

I am struggling to find any resources on keyspace and bitcoin addressing. Recently after looking at the puzzle transactions some questions came to mind. https://privatekeys.pw/puzzles/bitcoin-puzzle-tx

• What is keyspace exactly? is this refering to SHA256 keyspace?
• How is it that the puzzle transactions were created in different keyspaces?
• Can you create a bitcoin address in a specific keyspace?
• When bitcoin addresses are made is the keyspace they are in random, or is there a preferable or more pseudorandom range that they are likely to appear in?

Thanks for answering any questions.