I have been storing some crypto in Metamask wallet since early 2021. Last week, I opened my wallet and saw it empty. First I thought it was an error, but after reviewing the transactions, I realized my wallet has been drained out. About 5.6 WBTC (equivalent to 5.6 BTC) was sent out to some unknown address without my knowledge on June 15, 2022. 

Here's the history of my Metamask wallet: I installed the wallet on a desktop in early 2021 and transferred some fund into it. Shortly after, I installed Metamask wallet on my laptop using the same seed. So, I have the same wallet on two PC mirroring each other. A few months ago (around April) I installed the wallet on my iPhone with the same seed, so basically all three devices had the same wallet. Up to that point I had about 126K USD Coin in the wallet. On June 14 I swapped all the USDC for WBTC, with amounted to about 5.6 WBTC. All transactions were done through iPhone. A few days later I opened the wallet on my iPhone and was shocked to see that the wallet was empty. Some transactions were made on June 15, sending all the WBTC and ETH out without my knowledge.

Needless to say, it was a trauma for me. I was scrambling to find out how it happened. Did I download a rogue version of Metamask, or one of my devices was compromised? For the PC, I downloaded it from metamask.io. For the iPhone, I used Apple store. Here's a few things that may give clues to how the attack came through:

1) The fund has been in my wallet for months so if the attackers wanted to take it they could have done so earlier. It must be something I have done lately. One June 13 I downloaded some software and installed it on my desktop. The software was not related to crypto. At the same time, my Norton Security subscription just expired and I didn't renew it right away. So there's lapse of security on my desktop around the time of the attack. The desktop is used on daily basis and it is on most of the time during my work hours. 

2) All the latest transactions was done through iPhone, so I wonder if the attack could be on my iPhone? One thing I notice is that while all the latest activities are shown on my iPhone Metamask wallet, they are not shown on my desktop nor laptop wallet. All the transactions I made on June 14 (to swap USDC to WBTC), and the unauthorized transaction of sending WBTC out, are shown on iPhone, but not on desktop or laptop. Looks like someone has erased the transactions to hide them from me. Though I can view them on Etherscan.

3) I did not turn on the laptop in the week leading up to June 15, the date of the unauthorized transaction. I actually barely used my laptop to access Metamask.

Here's my wallet activities on Etherscan:
https://etherscan.io/address/0xbf0a095f3479847c8bf677e33046a5e7b5dcce94

I learned that I can store my BTC in hardware Tresor wallet and trade through Metamask, instead of storing the coin in Metamask itself. I wish I knew that sooner. I take my consolation in the fact that this is not all the BTC I have. I still have some BTC stored in Tresor wallet. If anyone is storing your coin in Metamask, I urge you to use Tresor instead. Use Metamask to trade only, not to store the key.

There have been talks about central bank digital currency (CBDC), a kind of cryptocurrency that is backed by a central bank. Recently, China is rolling out digital yuan, its own version of CBDC (curiously, it's not using blockchain). Even though China is not the first country to have its CBDC, it's the first major economy to do so. Some people argue that CBDC will make bitcoin become obsolete, as in this article:
https://seekingalpha.com/article/4418567-bitcoin-china-launched-digital-yuan-and-will-change-everything

People who support this view fail to realize that, while CBDC has some characteristics of a cryptocurrency, it is still very much a fiat currency. It can be inflated whenever the government wants to. It is not anomymous (one of the features that crypto users prefer). Users of CBDC do not have the freedom as crypto users do. CBDC may be a great contribution to the economy, but it will not replace bitcoin. In fact, I believe that CBDC may even make bitcoin more valuable. Why? Because with CBDC, it's easier to convert bitcoin to CBDC and vice versa, so people who hold bitcoin may not even need to use an exchange to convert their BTC to fiat, and people who want to buy bitcoin can easily do peer-to-peer transaction without using a bank account.

I long for the day when the Federal Reserve issues the digital dollar. It will make conversion between bitcoin and USD even easier, and we may not need to use an exchange service.

What do you think?

I am planning to buy some S19 Pro 110TH/s, possibly up to 10 units. I am undecided whether I should buy new or used ones. New ones are expensive ($15K-$16K now) but I guess I will get back the investment before they start breaking down. Used ones save me a few grands each unit, but I am not sure if I can get back my money before they break down. Since most S19 Pro are less than 1 year old, and I can get them fixed if they break down, maybe it's a better option?

Please advise. Thanks

I am new to mining. Can someone tell me what PCB stand for in this table (Miner normal operating temperature range):

https://support.bitmain.com/hc/en-us/articles/360005088914-Miner-normal-operating-temperature-range

My friend and I are planning to mine bitcoin at his home in Houston, TX. We plan to start with 1-2 Antminer S19 Pro 110TH/s and possibly up to 10 units. Which mining pool do you recommend? Does mining pool size matter. I see that large pools tend to have higher transaction fees. So if I decide to join a smaller pool, is there any disadvantages? Some pools like Genesis Mining or WinMiner even have no transaction fee. Is it worth trying them?

What is the most important factors you need to consider when joining a mining pool?

Please advise. Thanks

Lately there has been much talk about mining bitcoin with renewable energy. One company in Texas plans to do so:

(this board keeps removing my hyperlink so you can use google to find the following article on CNBC ):
"This Houston tech company wants to build renewable energy-run bitcoin mines across Texas"

One problem with solar energy is that it can only be generate during daytime. So the said company will power down their miners at peak time. That raises two questions:

1) If you powerdown your miners daily, will it damage the machine, or shorten their use life? Since bitcoin ASICs are only profitable for the first 4-5 years of their life and you will have to replace them to stay profitable, if they can last this long I assume it should be OK?
2) Solar power are only available during daytime so if you only run your miners 8-10 hour a day when the power is available, will you be able to make profit?

In my state California, electricity rate is expensive (I pay above $0.20/kwh on average). But California is one of  the best state for solar power so if I want to be profitable with bitcoin mining I have to think solar. Say if I build a mining farm using solar power and I have to power down at sunset, will it be profitable? Using battery to store energy for after-hours is an option but will the profit overcome the cost?

I know the S9 Antminer requires 220v to run, but I don't have 220v outlet now. I am waiting for the electrician to install it, and it won't be done for another week. While waiting for him, I would like to test run my S9 and learn how to set up. Is it safe to do so with 110v outlet?

I bought this machine earlier this year but haven't had a chance to work on it. I paid $210 for it, including the PSU, and am surprised when I see the price is more than doubled now. I know S9 Antminer is not profitable to mine bitcoin now so I bought it for learning purposes before I make any serious investment in mining machines. Why does the price go up?

I want to try out mining at home. I plan to buy an Antminer S9 and build an immersion cooling rig, like this one:

https://www.youtube.com/watch?v=8KlsoRAbey8

The question: do I need any speacial casing to cover the Antminer S9 before immerse it in liquid? I mean, can I just dip it in liquid and it still work as if it's in the air? What about the PSU, can it also be immersed or it has to stay dry, except for the connectors?

I know Antminer S9 is not an ideal machine now for ROI, but this is just a start. I want to get the experience first before I dive further into mining. Anyone who has experience in immersion cooling please share you experience. Thanks

At the time of this post, bitcoin is about $33,500, that's 20% off its peak last week. I have seen here and there people saying they regret that they didn't buy bitcoin before. Well, if you are one of them, this is your chance, buy it now. You don't have to buy a whole bitcoin, just buy whatever fraction of it that you can afford.

If you still hesitate, then you should never regret again, because you never would have bought it in the first place anyway, even when it was very cheap. There are people say "I regret I didn't do this and that..." but when the opportunity comes, they refuse to take it. They just say it because they feel envy to people who did, but they themselves don't want to take the risk.

Your choice: buy it now, or come back in the future and regret again?

I just bought a Trezor Model T hardware wallet to store 10,127 BTC.

I wonder how many failed PIN attempts are allowed before this device wipes itself out or locks up indefinitely? On Trezor Wiki it says 16 times then Trezor will wipe out data, but Google search returns different answer. Some Redit posts say there is no hard limit but after each failed attempt the delay time increases exponentially, and at some point the time is like infinity. There is also a story on wired.com about a guy forgetting his Trezor PIN and each time he failed the delay got longer. So which answer is correct?

https://wiki.trezor.io/PIN#:~:text=ImportantAfter%2016%20incorrect%20attempts,use%20of%20your%20recovery%20seed.
https://www.reddit.com/r/TREZOR/comments/2l9do0/trezor_pin_entry_number_of_allowed_attempts/
https://www.wired.com/story/i-forgot-my-pin-an-epic-tale-of-losing-dollar30000-in-bitcoin/

(No I don't have 10,127 BTC. It's a joke :=)))  )