Topic: Why not make Bitcoin more Secure with a PIN and TAN System? - page 2. (Read 2797 times)

There are two problems associated with this approach:
1. Storage space is limited in the block chain as it is mirrored on all clients. If you're allowing random clients save their TAN in the network, it could be easily spammed. So you would have to introduce a fee for saving TAN hashes in the network, similar to the transaction fee.
2. Online banking TANs with their 6 numbers have a very small search space which is only secure because your bank locks your account after 3 or so wrong entries. This is not possible in Bitcoin because you can brute force the public TAN hashes offline. Thus, the TANs must be impractically long like 30 characters or so.

Well, an attacker would still need to have my private key to be able to sign a different transaction with the TAN.

OTOH, if he already has access to my private key, he can just wait for me to broadcast a transaction (or keylog the TAN (Edit: assuming this is the way he also got the password for the soon-to-be encrypted key)).

you really don't know how it works, right?
as soon as you broadcast your TAN codes to the network, anyone else could take it and use your money.

scenario:
Node A, is your node. Node A knows Node B-Z, which you don't know anything about. Node B-Z was placed by an attacker, they are cancer nodes, they does not rebroadcast your transaction, instead they capture your TAN codes and gives them to the attacker.
this sucks.

you don't know any thing about this, and therefor you can only be protected from by publickey-cryptography.

Thanks for the first answer on this .

I know that Wallet encyption comes maybe, my focus is on the TAN system.
Like i wrote it should be possible in the same way like the Bitcoin-network saves
the valid transactions.
So why not just store valid TANs via hashs (encrypted, not plain) in the network too?
(when they are plaintext, everybody just harvest them :-), they must be
encrypted)

The interaction with the Network, could be done the first Time the wallet is created,
or with the help of a second communication channel.
(the Network generates the TANs and send them to a predefined emailadress so,
the TAN can printed out by another PC so the risk can be lowered)


I think that this would be a great soloution.

Wallet encryption is being worked on right now.

As for TANs, the thing is how to tell the network about your TANs?
Maybe a special kind of transaction which publishes the hashes of the TANs for one address. Later transactions from that address are only valid if they include the plaintext of one of the unused TANs. Could something like that possibly work?

mmmmh, no answers
it is too secure or to difficult? ;-)

come on people something should be done like this, i f i was a programmer i would do it my self.
But i am not, so i can only support Bitcoin by running the client, do a little mining
and Share my Ideas of  improvements for Bitcoin.
I really think the Idea of Bitcoin is good, but the security is really like russian roulette on windows machines ;-)

I read the Disscussion here,
and i must say that the wallet design is a security Joke,
dont blame the "windows cunts" for this, like i read here for that fom a Linux-fanatic
(i also was young so i could understand it, but i am older now ;-).

Now it is secure like a Creditcard where the "security code" is on the backside ;-).
A thiev could just copy the wallet - and that is not a big deal with a trojan, and easyier to steal.

Why not use/implement a system which could secure the money inside the wallet
like a TAN & PIN Combo? (Transactioncode & Personal Id Number/Password)
(not only encryption alone, because the TANs make the improvement )

1.TANs:
- The idea is that the user gets instead of 100 adresses only 10, but he gets
  100 TANcodes which are synced with the Bitcoinnetwork (Similar like DHT on Bittorent,Distributet Hash Table)
  and work for all these 10 Adresses so he could print the Tans out and delete + shredder the TANfile (or better: it could also just diplayed+printed once
  or saved to an USB without disc acces and printed later)
- Maybe this also could be done over a second communication Channel if needed, like PGP/GPG email.
  (downloaded with another PC so a trojan could not know for which adresses  this TAN list work)
- These TAN codes should be used with mouse only (an virtual keyboard should displayed to click the Numbers)
  The numbers could be Decimal or hexcode (0-9 & A-F) which is also practical.
- The order which the numbers display on this virtual keyboard should be randomly
  switch for every new transaction, and should not be possible for a trojan to read out of the RAM.
  (The client only sends mouse positions, no numbers)

2.PIN,Wallet Encyrption and possible splitting:
- The Wallet should be encrypted and passwordproteced
- It should be possible to import and export different wallets (every wallet with own password offcourse)
So the user could manage better the risk and Money.
The solution is for example, that BC-Client finds and accepts all files in the programm directory with the name wallet_*.dat (*=a unique name)

So the Advantage is not only the security,
with this system it is possible to run a client 24h without fear, to support the network.