I have two computers, one of them is airgapped.
I had also two MEW private key, stored in the airgapped computer, I made a lot of transaction from the first private key to the second one.
I have made several transactions using MEW OFFLINE and recording several signed transactions and addresses on the computer with Internet (but not the private keys)
So on my computer with internet has been recorded addresses in which to send the coins TO and FROM + all the signed transactions made time after time
all recorded in the on line computer
Remember this part because it's important.
Well, one day I decide to use MEW ONLINE ONLINE so I write in plane text one of my two private keys in the on line pc and I drain the wallet sending the coins to the second Myethereumwallet I had (remember at the start of this post I told you I had two MEW wallets?)
Well, a potencial attacker could have recorded in the on line computer thes things:
1) addresses of the two wallets
2) all the signed transactions made between these two wallets
3) One of the two private key used only one time on line to drain the first MEW wallet and to transfer the coins to the second MEW wallet
With all those informations could an attakker build up a pattern to decrypt the second private key?
I remember you that he could have addresses + one private key + all the signed transactions made between those two wallets