Hence, in FinderOuter, I have last six unknown characters and one unknown character in the middle of the key as basic search. I am replacing F with H,J,K. This search will take a very very long time for completion.
This search is trivial to do if you set up btcrecover properly. You have three unknowns for the first character, and 58 unknowns for the character in the middle. Even assuming the worst case scenario of the checksum only being 5 characters, giving you another unknown character in the 6th from last position, then there are only 3*58*58 possibilities, since the last 5 characters don't need to be brute forced since they will be calculated from the rest of the key. This is only 10,092 possibilities, which can be searched in under a second.
Thanks for your response. I am trying to install BTCrecover on Ubuntu 22.0 but it is having issues with Ripemd160. Ripemd160 is not working and tests are not working.
I assume the last seven characters on a private key is based on checksum then the search would have been 3*58.
I tried it on FinderOuter but the search is 3*58*58*58*58*58*58*58*58.
Ie 3=first character after 5.
Than 58 for one invalid character.
Then last seven characters for checksum ( 58 x 7 ).
Had FinderOuter provisions for elimination of checksum and calculated only the main characters then the search for valid key would have been very simple.
If the seller who emailed me the private key has given me a valid key.
As one of the response stated that if the seller has scammed me then none of the above search efforts are of any use.
Hence, currently the task is unpredictable.
Thanks