Firstly understand that a BTC "address" is *not* a public key - it is a RIPEMD hash of one (with a trailing checksum).

Your public key is revealed when you "spend" funds that were previously sent to one of your "addresses". Although this doesn't disclose your private key if the ECDSA algo that Bitcoin uses was to become "compromised" then any funds sent to addresses from which you've spent could also become unsafe.

So it is not recommended to re-use addresses (or if you do then sweep the funds to another address as quickly as you can).

Well that is something I think we can all agree will be a great additional feature for bitcoin-qt!

Indeed - it has been pointed out many times that brainwallets are not something that most should even consider using.

At the very least if someone is considering using a brainwallet then the "pass phrase" that they use should actually be something that has first gone through some sort of hashing algo through multiple passes (and better to use multiple algos).

Although of course one would never recommend starting with "correct horse battery staple" but I would guess that if you hashed that say 99999 times (and of course now that would be useless because I just wrote that) then it would be a hell of a lot safer.

Bear in mind with broken RNG implementations you could also lose your BTC by just using a supposedly "random" address.

In that case I think there must be something else wrong with your wallet (which I haven't heard of before) - if anyone else has some ideas now would be about the right time to chime in.

Well depending upon "how small" it may be possible that you don't have enough to pay a tx fee (although 0.08 BTC would seem quite a lot even if you have a *lot* of small amounts).

Perhaps try a smaller amount (say 1.0 BTC) first to make sure that this isn't the case.

That is unusual then - if you don't mind me asking were the BTC you received in just a few txs or were there many small ones (this could affect things although hard to believe by that much)?

Okay - I haven't heard of this exact problem before - but just to make sure - are the 2.08 BTC funds you have already confirmed?

And are the funds you are wanting to send already confirmed?

You'll need to provide a bit more information to get help with this - for a start what client or web wallet are you using?

Caps is not relevant for the hash value when it's displayed as hex (i.e. it can be shown using either upper or lower case letters but is still the same hash value regardless).

Yup - from where I am connecting through I see 109.201.133.195 (from where I am actually located I see 108.162.196.161) so I think I am fine (did also check the SSL cert fingerprint matched the one that theymos signed).

Wow - I am communicating with someone from the future!

As I have checked and verified the certificate's fingerprint then I am assuming that I am okay.

Was this written from someone in the future?

It is currently 04:24 Dec 2 UTC (if it was meant to say 20:00 Dec 1 UTC then luckily I was getting CloudFlare errors that whole time).

Hmm... a bit of re-arranging and I come up with:


Not quite right - but is looking closer to a possible message.

I guess there are some "coin collectors" who value them being left in "mint" condition so I can *get* that although I've never been such a collector myself (I did have a stamp collection when I was a child but ended up swapping it for some toy cars).

Really? I have seen a few of his coins and every one I've seen was already *spent* (but that's only a few of course).

Also I don't quite see how spending the BTC would *destroy* the physical coin - it is made of metal after all (and if that didn't matter then why bother with it at all?).

I don't think for a second think that Mike Caldwell would try and steal BTC and I do think his heart was in the right place (and his coins have been pictured everywhere) but I don't think that "physical" bitcoins (kept *intact*) are really that worthwhile a collectible (a reason I never purchased one nor am likely to ever want to).

Actually it would indeed benefit you if RMB increases in value - but I would caution not to leave BTC or RMB (or USD or any other currency) in an exchange for a long period of time.

It actually is very easy to open a bank account in China (you just need to bring your passport with you to a bank branch) so maybe you should consider setting up an account here (it's also possible to get very good interest rates for savings at the moment).

One thing you might want to consider is that China has recently stated (officially) that they are not going to buy more USD debt (and may even sell off the USD they are currently holding).

Although not clear how this will pan out yet it is quite possible that the RMB will become more valuable (especially in comparison with the USD) so your plan might backfire simply because of this (of course if you factor this in then maybe it won't be a problem).

The danger is that if the ECDSA that Bitcoin uses is somehow able to be broken (and so far it would appear not to have been) then it might turn out to be relatively easy for someone to determine your private key from your public key.

As an address is not your public key but is instead an irreversible hash of it then provided you never re-use an address the likelihood of being able to lose funds even if the ECDSA is broken would still be very, very low.

The public key is included in the script for spending UTXOs (inputs) so that anyone can verify that you do have the private key (an important reason why it is not a good idea to re-use addresses).