Bitcoin armory system requirements
On the online computer, click the Offline Transactions button on the right, below the logo. Select Create New Offline Transaction. A window will open with the unsigned version of the transaction. Load the file from the USB key, then press the Sign button. A confirmation window will appear. Verify the confirmation details before you sign it!
Click Save to file…. Eject the USB key and plug it into the online computer. If the original window is still open, you can click on Next Step to get to the broadcast window. If you closed Armory since then, you can use the same Offline Transactions button on the main window, and select Sign or Broadcast Transaction. Once the file is loaded, some green text should appear telling you that the signature is valid and the Ready to Broadcast!
Guidance is given at each step within the Armory software, so you may be fine without referring back to this page. And once you do this a few times, it will become a breeze! At no point in this process is any private data exposed through the transaction data.
It is perfectly safe to transfer the signed or unsigned transaction via email. The biggest threat to an offline wallet is a USB-key virus that executes when plugged in. However, such viruses would have to be highly targeted, and can be mostly mitigated by disabling USB-auto-run on the offline computer. So, how do you calm your nerves about using such advanced features? Try it out with small amounts of Bitcoins. Whether it takes you a day or a year, you will eventually come to realize that offline transactions really do work.
Make a new wallet as described above, but you must make a backup. A digital backup is fine if you make a couple copies, just in case one becomes corrupted.
Generate some addresses by clicking on Receive Bitcoins a few times. Write down the first few letters of each address generated. Why did we just delete it? If you can restore the backup once, you can always restore the backup at any time in future. On the main Armory window, click on Import Wallet in the upper-right corner, and select the type of backup you are restoring. Generate some addresses with the new wallet. Check that they are the same as the addresses you wrote down earlier.
Import the watching-only wallet on your online computer. Generate a few addresses and compare to the ones you wrote down earlier. The change address is important because sending coins back to the original address reduces your privacy.
In other words, if you have exact change. Change addresses are a normal part of wallet operation, and are intended to be mostly transparent to the user. They should not be treated differently than any other addresses. Bitcoin is decentralized so there is no central authority that determines the validity of transactions.
For instance, if two people swipe the same debit card at two different stores, the bank that issued the debit cards decides which one to accept if funds are only available for one. Bitcoin does not have a central authority, and thus cannot make instantaneous decisions like that. However, Bitcoin does have a mechanism for resolving this problem, it just takes time for the network to reach a consensus about it.
Every confirmation your transaction receives is more confidence that your transaction will ultimately be accepted by the network. Each confirmation takes an average of 10 minutes.
It is a good idea to wait at least six confirmations for any important transactions, though two or more is sufficient for small to medium-sized transactions. Most zero-confirmation transactions will become final, but there are no guarantees! Use the following list as a guideline for how to treat transactions:. If you are accepting transactions that are big enough to change your life, it is recommended you even wait 10 or 20 confirmations. Each bitcoin or fragment of belongs to a cryptographic private key , which is an digit number that is essentially impossible to guess.
Bitcoins cannot be transferred unless the holder of the private key uses it to create a digital signature authorizing the transaction. Every Bitcoin address you ever give to other users, corresponds to a different private key in your wallet, and you are the only person on the planet who has access to those private keys. This means two things:. Bitcoin transaction fees are a confusing topic, and understanding exactly how they work requires bit of technical background on how Bitcoin transactions work.
And most of these properties are invisible to you and out of your control. Luckily, these fees are usually no more than 0. There are a few observable things that will require a fee, which you may be able to avoid:. In the world of heavy computing, researchers are always looking for ways to crunch numbers faster.
In the past few years, it has become popular to use video cards — normally used for playing graphics-heavy computer games — because their graphics processing units GPUs can parallelize many types of computation and get x to x speed-up compared to using CPUs. While GPUs are not good at every kind of computation, they have proven to be quite useful for brute-forcing encryption passwords!
For this reason, the encryption scheme used to protect Armory wallets was designed to be difficult for GPUs to perform.
Specifically, GPUs can perform many cryptographic operations very quickly, but have only a tiny amount of memory to work with. A few very talented Bitcoin experts were able to piece together offline tools for their own use, but no solutions existed for the average Bitcoin user.
Armory innovated access to Cold Storage. This watching-only wallet functions exactly like a regular wallet, but it does not contain any private data, and thus cannot spend your Bitcoins making it useless for an attacker.
However, it does let you generate new addresses, and verify incoming payments the same way a regular wallet does. The transaction can then be brought back to the online computer to be broadcast finalized. More information can be found on our Cold Storage page. However, the Bitcoin network supports much more complicated transactions that require the signatures of multiple people before the funds can be transferred.
These are often referred to as M-of-N transactions. Here are some examples:. Husband and wife petty cash account — the signature of either spouse is sufficient to spend the funds.
Husband and wife savings account — both signatures are required to spend the funds, preventing one spouse from spending the money without the approval of the other. One wallet is on your primary computer, the other on your smartphone — the funds cannot be spent without a signature from both devices.
Thus, an attacker must gain access to both devices in order to steal your funds much more difficult than one device. A board of three directors maintaining funds for their organization — those funds cannot be spent unless any two of those directors agrees. Bigger multi-signature transactions are possible for bigger organizations, such as 3-of-5, 5-of-9, etc. If transaction goes smoothly, then both buyer and seller sign the transaction to forward the money to the seller.
If something goes wrong, they can sign a transaction to refund the buyer. If they cannot agree, they both appeal to the third-party who will arbitrate and provide a second signature to the party that it deems deserves it. Why Is It So Inconsistent? For reference, the following is the default location for the Armory wallets and settings: Use the following list as a guideline for how to treat transactions: This means two things: If you lose your wallet, the coins you own are lost forever solution: