Well not exactly, as I understand it you could attack the passphrase protecting the key. If you remember any details about this passphrase then you can dramati

Well not exactly, as I understand it you could attack the passphrase protecting the key. If you remember any details about this passphrase then you can dramatically reduce the strength? (I'm not sure of the word to use here. Someone help me out) of said passphrase. But yes, if someone was able to crack keys in a reasonable amount of time then bitcoin would crash overnight.