How safe is Bitcoin really?

[traderbit]

Basically bitcoin is safe, but the transaction can not be confirmed if the "stress test" is alive at that time.
So in generally bitcoin is safe, but the way how you generate the address, wallet, private keys this can be dangerous.
Recently brainwallet addresses were 'hacked', the sensitive information has been bruteforced and people lost their bitcoin.

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[Mickeyb]

Bitcoin as a network and an algorithm is as safe as it can be. Almost 7 years running without any huge problems with surely many hackers all over the world that tried to harm it.

Where the problems come are the third parties wallets, software, exchanges, web wallets and also user ignorance. Also let's not forget malware. This is where all of the Bitcoin problems arise!

[christycalhoun]

Wallets can be hacked no matter what. I would do some research and learn how to make your own backups. Don't put it all in one place.

[Rude Boy]

Bitcoin is the safest one but, the wallets are vulnerable. Each and every wallet having possibility to became hacked. Even cold wallets beacuse, nowadays virus doesn't needs internet to spread -> http://thenextweb.com/apple/2015/08/04/macs-are-no-longer-immune-to-attacks-as-a-new-self-replicating-firmware-worm-demonstrates/

[Hugroll]

How hard is it to hack an online wallet?
Can your transactions be stuck in limbo without confirmation?

the private keys are safe if only you know what they are , dont use a webwallet where a 3rd party is in control of the keys because then u arent trusting bitcoin, you are trusting the 3rd party

[OROBTC]

as far as i know its not too hard to hack online wallets but if you have a paper or hardware wallet its nearly impossible to do that

Exactly. That's why people who want to store their mass of bitcoins in a secure place always obsess over paper wallets, and reputable and trustworthy escrows usually buy a Trezor hardware wallet to store escrow funds.

Any other wallet (such as web wallets or wallets on your computer) are extremely vulnerable and you can never assume that they are safe unless they've never touched the internet before.

I was looking for the right post to quote...  

I once did have a problem with blockchain.info.  My wallet got emptied by them!  I believe I was using their 2FA (which I could never get to work right) at that time, but maybe not.  I do not know exactly what happened, but I did get my BTC back after a little back & forth with them.  It might have been some kind of programming error while they were maintaining (or upgrading) something.  Others had that same problem that night.

That taught me to keep the large bulk of my BTC in my Trezor and Ledger Nano.  My BTC holdings on the two devices is roughly 50/50.

[StevenLiang]

It's quite safe to put your money on wallet. Nothing bad can happen if you keep your stack online.
Would you keep your stack of gold in the middle of the street inside a box? Sure not, even if it's inside a box, it's "out there".

If you really worry about your online wallet, you can make offline wallet.

[doublemore]

How hard is it to hack an online wallet?
Can your transactions be stuck in limbo without confirmation?

Bitcoin for people new to it isnt that safe atm for various reasons, even if you get everything right you can find your money becomes worthless.  We have been stable for a while now though which is great!

[prodigy8]

Once you get your bitcoin in your wallet i think you are safe.
But try not be a victim of hackers that may send you different emails saying that we need the private key.
Or sometimes they ask to export your wallet un-encrypted, by this way you can lose all your bitcoins.

[pooya87]

as long as you are doing the transaction signing online it is not safe

you should learn how to make an offline wallet, sign a transaction on that offline wallet and then broadcast it on another PC which is online.

[Light]

In theory nothing is completely safe. There is always risk - it's just how much risk your comfortable taking and whether the trade-offs are worth it.

For most people they'd either be comfortable having their wallet on their computer. It's better than having it on an online wallet but obviously not as good as cold storage or a hardware wallet. Cold wallets are too much hassle for small transactions - and if you deal with BTC on a daily basis and in different locations - an online wallet for small transactions (i.e. hot wallet) could easily be justified.

[BTCBinary]

Bitcoin is very safe if you know how to use it and store it. Depending on the type of use you want to give it you will need use different kinds of storing.

[mirana12345]

Bitcoin's safety is proportional with users intelligence. Sadly, there are still alot of people that don't quite understand how it works, and those who have no sence of security,
so they end up being robbed or/and scammed. With time, there's no doubt the levels will rise, and we no longer will have such problems.

[Cereberus]

In theory nothing is completely safe. There is always risk - it's just how much risk your comfortable taking and whether the trade-offs are worth it.

For most people they'd either be comfortable having their wallet on their computer. It's better than having it on an online wallet but obviously not as good as cold storage or a hardware wallet. Cold wallets are too much hassle for small transactions - and if you deal with BTC on a daily basis and in different locations - an online wallet for small transactions (i.e. hot wallet) could easily be justified.

Yes this is sad but true in any situation. Build a fortress and eventually there will be a point of access over time.
But it can be fortified if found out before it is accessed not after to keep it from happening.

[Cereberus]

Bitcoin is very safe if you know how to use it and store it. Depending on the type of use you want to give it you will need use different kinds of storing.

This is the most important quote for people that use bitcoin to understand.

Bitcoin's safety is proportional with users intelligence. Sadly, there are still alot of people that don't quite understand how it works, and those who have no sence of security,
so they end up being robbed or/and scammed. With time, there's no doubt the levels will rise, and we no longer will have such problems.

An intelligent user is an informed user of the pitfalls that anything bestows. With the good comes the bad. Just have to be aware where those bad things are and how to deal with them once encountered so they don't fall into a trap like others have fallen into before them.

[dothebeats]

bitcoin into on itself is not vulnerable. The web wallets and hard wallets are.

Just spread out your bitcoins across several different wallets. If one gets done in you have others to continue with.

There are certain exploits that an experienced coder could do to somehow disrupt the whole network, just like the transaction malleability problem. Bitcoin. though secure, still has an attack vector on its code, but exploiting it seems to unlikely and only devs with knowledge in this could use it for their own gains or fix it. Remember the recent surge of unconfirmed tx? That is the malleability problem exploited by a single user.

[teddy5145]

The bitcoin itself is pretty secure, sometimes most of the people who got their btc wallet hacked or stole  is on their own fault
If you are using online wallet and wanted to beef up the security try to turn on 2FA

[n2004al]

It's possible to hack an online wallet, but it's almost impossible to hack a wallet installed on your computer if you have also installed up to date antivirus software and a firewall. If you control your Bitcoin private key generated by your wallet installed on your computer then your Bitcoins cannot be stolen by directly hacking your Bitcoin wallet. The only way your Bitcoins stored on your computer can be stolen is if your computer gets hacked, or infected with a virus.

Online wallets are sometimes hacked, but whoever runs the online wallet controls your Bitcoins, and how secure the wallet is depends on their coding skills.

If an online wallet is hacked that doesn't mean that you can loose for sure your bitcoins. Depends in which online wallet they are stored. I use Coinbase and this wallet keep up to 97% of customer funds stored offline. So even if hacked the hacker will have almost nothing (if will have the possibility or the chance to find those 3% bitcoin remain online). This is the first thing. The second is that no one from the part of wallet (employee, manager, owner or whatever it will the human kind which work with Coinbase) have no possibility to touch my bitcoins. According to Coinbase Blog of October 29, 2014 with the title "Introducing Multisig Vault - You Can Now Control Your Own Private Keys On Coinbase":

"Our new Multisig Vault gives the customer complete control of their own private keys.  Coinbase has no ability to move funds (which means you are safe from Coinbase being hacked, going bankrupt, or anyone seizing your bitcoin).  It also means that you as a customer have much greater responsibility in storing your backup key securely.  If you lose this backup and forget your multisig password, Coinbase cannot help you recover your bitcoin.  For this reason, we only recommend this feature for advanced users."

I don't use this Multisig because I am not an advanced user. But even the hacking of the wallet itself is very hard to be made. In my account can be entered only after the put of the code which come to my phone or to my account at Authy (which have my phone number). So it is not very easy. It is not at all easy. But this is not all. Bitcoin stored on their servers is covered by their insurance policy. According to their site:

"Coinbase is insured against employee theft and hacking in an amount that exceeds the average value of online bitcoin it holds at any given time. Specifically, Coinbase's insurance policy would respond in the event that bitcoin stored in Coinbase was lost or stolen as a result of a breach of our physical security, cyber security, or as a result of employee theft."

"Coinbase has held this insurance since November 2013 with highly rated carriers (S&P rating of A+ or A.M. Best Rating of A XV or higher)."

[erikalui]

Any online wallet/bank can be hacked and it's easy for hackers but not for a lay man. It's better to use wallets that require authorization by 2 or more account holders/users to withdraw the bitcoins or wallets like Xapo which require me to enter an OTP while logging in the wallet. It's not easy to get the PWD and the OTP of a person's mobile number to hack a Xapo wallet but there can be extreme cases.

With regards to transactions that aren't confirmed, the transaction is just not counted as there are users who have faced this and they instead try the double spend method to recover their coins else the coins are just stuck. No clue when such transactions get cancelled by the network.

[MrsHash]

Don't forget that everything can be hacked. Once it somebody created, there would be someone who would be able to hack it, I am sure. So it is like a bank, it would be stupid to put all your savements in one place and hope that it's 100% secure and nobody would touch it except you. I recommend you to use both offline and online wallets.