Thanks that helps. The issue I am still having is that when a address sends btc and I look at the scriptsig and extract the last 130 hex characters and enter it it the tools suggested in this thread it doesn't have any relation to the address or it's an invalid public key.
As a worked example... have a look at this recent tranasction:
https://www.blockchain.com/btc/tx/bee2768770f68a31543eda6fd40da75e4432f434cf8c3312497cdeebb4a2ac6cIf we look at the sigscript:
47304402200c794238b992fbdda63b1606edc07c5b48a29e003e7cf9d4894baa7baf3b063b022012ed8593d439dc05e3639d60434028e8b0a2207a139ec58bf5e719e019f09485012102ebb666614f5faff4aa43e5f1be868ebc5f1be67c8553924410d8d0111a9912d2
Firstly we try the final 130 chars:
8593d439dc05e3639d60434028e8b0a2207a139ec58bf5e719e019f09485012102ebb666614f5faff4aa43e5f1be868ebc5f1be67c8553924410d8d0111a9912d2
Doesn't begin with "04", so it's not an uncompressed key... not surprising, given that it is a relatively recent transaction and most legacy addresses used today will be using "compressed" keys.
Then we try the final 66:
02ebb666614f5faff4aa43e5f1be868ebc5f1be67c8553924410d8d0111a9912d2
"02", so it's likely a compressed public key... if we put that into
the Address tool I listed earlier, we can see it outputs:
Which matches the bitcoin address from the transaction:
NOTE: This tool was not designed for "compressed" keys... it
will complain that it has an "invalid public key length":
But it
will still generate the correct address.
Now, let's look at this much older transaction:
https://www.blockchain.com/btc/tx/b9d69463c500b81dc2ff600d0b528b15fb816c4dab11e424151de0bcbea7f26fThe sigscript of the first input is:
473044022018c35ebde490ca56f6d073a20ec3199f461ee9c99d2c020fdecd8711bdb9cc5802205fd0ce0f61ee2566cafd4254bc1d34a4fcf02d2a55c281a0a95a8c332bff2443014104f52193d56ffda6ef5fbc3b4ada7768c347321f47f1a999b0ca9b8374d8228275ee2c1ecf45c718538288667ad367f97a00116bd0630c76cc01f26161ce70057a
The last 130 chars are:
04f52193d56ffda6ef5fbc3b4ada7768c347321f47f1a999b0ca9b8374d8228275ee2c1ecf45c718538288667ad367f97a00116bd0630c76cc01f26161ce70057a
Starts with 04... quite likely an
uncompressed public key... So, feeding that into
the tool:
And we can see the address checks out: