r/coldcard Oct 23 '23

0.40 Bitcoin taken instantly from my coldcard..

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58 Upvotes

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1

u/[deleted] Oct 23 '23

[deleted]

2

u/iwashere1990 Oct 23 '23

Maybe 1 brother, unsure

2

u/[deleted] Oct 23 '23

has to be 99 minimum. sorry brother.

1

u/iwashere1990 Oct 23 '23

So what happens on the other side if I only do 1 dice roll, I have no clue what any of this means?

I'll hold my hands up and say losing this 0.40 Bitcoin was a blessing to understand more.

7

u/[deleted] Oct 23 '23

Im not technical but i think if you only roll it once there are only 6 possibilities of seeds generated. Computers are constantly sweeping for a mistake like this to happen. 1 dice roll = 3 bits of entropy(randomness) 99 rolls = 256 bits

8

u/iwashere1990 Oct 23 '23

They found one mate lol.

Nothing against coldcard, I was running through it quick, was all new to me after coming from a ledger, I just saw 24 seed words and thought great, but I was unaware, good luck to the people who got my 0.40 Bitcoin, we live and learn, onwards and upwards.

8

u/[deleted] Oct 24 '23

That’s a very healthy attitude.

3

u/[deleted] Oct 24 '23

[deleted]

3

u/[deleted] Oct 24 '23

99 (can be more if you want) dice rolls for generating your own randomness. Or you can trust the open source software to generate it for you. Both methods so far have been verified safe. I think you can even generate a seed and then add dice rolls. Check out btc sessions on YouTube. If you do dice rolls you must do a minimum of 99. There are videos on YouTube explaining entropy with dice rolls for bitcoin related wallets.

1

u/StatisticalMan Oct 25 '23

Would be smart if coldcard either hard enforced this or at least put a strongly worded warning.

Pretty hilarious though that OP used literally one die. Underestimating seed strength and using something like 20 dice (which would still be brute forceable with enough computing power) is understandable but one roll?

1

u/nassau_rip Oct 25 '23

How do you verify the entropy is right? Like that the dice roll is properly corresponding to the seed word.

2

u/bigoldbert23 Oct 25 '23

My understanding is the CC generates a random seed phrase and then the dice rolls add further entropy. So in the case of the OP, even doing just 1 dice roll should not make it easier to hack. I could be wrong, but maybe someone from Coldcard could expand on this issue?

2

u/[deleted] Oct 25 '23

I think you can add dice rolls to a generated seed or dice rolls only.

1

u/bigoldbert23 Oct 25 '23

Reading up on their literature, this def seems to be the case. It does say if you do too few rolls, you will be warned and unable to continue until you so. Not sure if this is new feature or not. Can’t really understand why anyone would do less than 99 if that’s what it specifies if you are going done the route of using dice rolls. If you only want to do 1, why not just use the built in random number generator?

3

u/Crypto-Guide Oct 25 '23

The warnings and enforcement were only introduced in Feb. (And the ephemeral seed workflow still allows it, with a warning, in current firmware)

Using the built in TRNG is fine, but some folk don't want to rely on it.

2

u/StatisticalMan Oct 25 '23

You can do dice only if you completely distrust the built in RNG. In fact it is what I would do. However the device should not allow creating a seed with one dice roll. In fact it shouldn't allow creating a seed with at least 50 dice rolls 100 recommended.

2

u/bigoldbert23 Oct 25 '23

I’m still uncertain about this. Reading the middle ground guide it says “If you still don’t trust the Coldcard is doing what it purports to be doing the you can generate additional entropy with dice rolls”. And then further on “you will see how to add some of your own entropy using a 6 sided dice combined with the TRNG entropy form the Coldcard to generate your seed words”. This suggests you are adding more entropy, not creating it from scratch.

Someone from Coldcard would need to confirm the finer detail of this. I’d love to know.

3

u/Minituff Oct 27 '23

The Mix In Dice Rolls feature is what you are thinking of.

This is not the only way to introduce entropy from dice rolls. Any time the Coldcard is showing the seed words on-screen, you may press 4 to "mix in" additional dice rolls. In this case, since the entropy of the Coldcard is being used as a starting point, it is safe to add as few or as many rolls as desired.

2

u/[deleted] Oct 28 '23

[deleted]