Is there any plan to incorporate "
hidden private key" feature for "
plausible deniability" to "Bither" wallet (as detailed in the OP of "
https://bitcointalk.org/index.php?topic=361386.0")?
This would be a very useful feature to
protect against violent physical theft of bitcoins, and I think up to now it is not implemented in any wallet software yet.
Generally, everybody is concerned about good technical cryptographic protection (for very good reason of course!!). But we should also be concerned about PHYSICAL theft: What if someone points a gun at me to hand over my private keys?! --> There is a very simple and effective solution of how a user can give his private key to a thief while still keeping his life savings.
This scheme could be implemented in both BitherCold and BitherHot (in the latter case for the "hot private keys").
I am not going to repeat how it works exactly here, because I have detailed it in the link above, so please just refer to that post to understand the motivation and the solution, but in short, the basic principle goes like this:
HiddenPrivateKey=sha256(NormalPrivateKey||MoreOrLessSimplePassword)- with "||" denoting simple "concatenation",
- with "NormalPrivateKey" being the private key as it is stored in the Wallet software today, and
- with "HiddenPrivateKey" being a temporary key calculated upon the user's selection of the NormalPrivateKey's Address and typing of a password. This hidden key should only reside in RAM memory temporarily while the user makes a transaction, and never leave any traces in flash memory. Obviously, the user should also not store the address of this hidden key in his list of watch-only-addresses, because this would render it less plausible to deny possession of that key.
Clearly, if someone steals the phone and knows the PIN, he can access the NormalPrivateKey but has no idea that another (or several other) "HiddenPrivateKeys" even exist.
The method is good for BitherCold for evident reasons (theft protection), but also for BitherHot if I want to take some Bitcoins with me on a journey but don't want to loose them all if I move with my smartphone into an unsecure neighborhood and get robbed...
