Security issues with the design or implementation of Bitcoin and related crypto-currencies.

learn more… | top users | synonyms

1
vote
2answers
29 views

How does a Trezor passphrase prevent restoration of a wallet if an attacker knows the seed?

Trezor User Manual says if you forget the passphrase there will be no way to recover your bitcoins. Not even the Recovery seed. How is it that you (or an attacker who knows the seed) can't just ...
2
votes
2answers
36 views

Can a Trezor seed be used in any other HD wallet?

Trezor FAQ says If you do not use a passphrase, your recovery seed is all that is needed to access your bitcoins. If you do not use a passphrase, can the Trezor seed be used to recreate a ...
2
votes
2answers
80 views

What is it about a Trezor that means it can't be infected by malware?

The Trezor testimonials include that TREZOR ... cannot be infected by malware What is it about a Trezor that means it cannot be infected?
0
votes
3answers
57 views

How can an online wallet be more secure than paper wallets or cold storages?

Recently, after I was reading that some bitcoin early adopter lost 750 BTC due to theft from his macbook, I was looking for the most secure storage solution for my coins. I already know about paper ...
0
votes
1answer
24 views

How can address' hash160 be used to determine information for malicious purposes? (Ie reusing of the same address)

I've been playing around with Richard Kiss's Pycoin app which is clarifying how P2PK works. I see that the hash160 of the value: (0x04) (x-coordinate) (y-coordinate) (for an uncompressed Testnet ...
0
votes
2answers
42 views

Hash property resistance

I'm experimenting with some self study cryptography and I was curious about the two following scenarios (simple answers and/or in relation to bitcoin) If SHA256 was found to lack pre-image ...
1
vote
2answers
55 views

Can you encrypt not just the private key, but also the public keys (ie bitcoin addresses) in an Armory wallet?

I would imagine that the paranoid darknety bitcoin user has an interest in keeping not only their private keys safe (so nobody can steal their bitcoins), but also has an interest in keeping their ...
1
vote
2answers
38 views

Theoretical security of mining bitcoins

Is it possible to change rules of mining bitcoin division? rewrite P2P bitcoin client (or write maleware) which will be pretending that fake bitcoin client is legal, original client distribute ...
0
votes
1answer
23 views

How do I reset my TFA token in Coinbase?

I would like to move my Coinbase Two-factor authentication token from one device to another. I cannot find a location on their website to disable TFA once it has been set up, or to move the token to ...
2
votes
1answer
28 views

How secure is calling bitcoind JSON-RPC from same computer?

I am wondering if calling JSON-RPC from the computer it is running on is secure. I read How secure is calling bitcoind JSON-RPC? and understand why it is insecure to do so from a different computer. ...
1
vote
0answers
80 views

Standardize wallet format [closed]

What's the status of wallet format standardization? Is there any proposal or work-in-progress around? If not, how come nobody urges to define standard wallet formats yet? This is especially needed ...
3
votes
1answer
82 views

New to Bitcoin - tips on securing my server

I regard myself as being a competent programmer and have good general IT knowledge; however I know very little about BTC. I just want to make sure that my setup is "generally secure" and that I'm ...
2
votes
1answer
58 views

How to securly move bitcoins from a wallet.dat file to a paper wallet? [duplicate]

I have an old wallet.dat file with a few Bitcoins. It is stored in an isolated computer that is not connected to the internet. I would like to get rid of the wallet.dat file, and move all the ...
1
vote
0answers
26 views

How do mnemonics encrypt wallet data and what prevents hacking of the algorithm?

How do mnemonics encrypt wallet data and what prevents hacking of the algorithm? For example Blockchain seems to encrypt all data using a mnemonic yet doesn't hold customer data server side. What ...
1
vote
1answer
91 views

How does CryptoNote prevent a 51% attack and double-spending?

How does CryptoNote prevent a 51% attack and double-spending? I’m interested to know what is the mechanism that protects CryptoNote coins from 51% and double-spending attacks.
0
votes
0answers
22 views

Ensure Wallet consistency

I have recently migrated machine. I used the Apple Migration Wizard and when it was finished my new machine's copy of Multibit appears to have my BTC within it. My next task is to wipe the old ...
2
votes
1answer
57 views

What is Mt. Gox's YubiKeys' “configuration protection access code”?

Does anyone know if Mt. Gox, now that they're bankrupt, has released their YubiKey's "configuration protection access code" (cf. this)? If so, we could reprogram the free YubiKeys they sent us and use ...
3
votes
1answer
66 views

What are some of the pitfalls of a 100% proof of stake currency (pos) like NXT?

Bitcoin has the vulnerability of a 51% attack for a proof of work currency, but what pitfalls does a 100% proof of stake (pos) currency have like NXTcoin?
2
votes
1answer
90 views

Bitcoin security, what is wrong with my thinking? [duplicate]

Lets assume I keep generating random public keys with their matching private keys and never use them. Severals years later I am checking for positive match against the blockchain for all my generated ...
6
votes
2answers
148 views

Does GHashIO already have above 51% hashrate?

Right before writing this question I noticed the GHashIO showing 32% hashrate distribution using the following link. Unknown has 26%. And the IP address of the most blocks reported from unknown is: ...
5
votes
4answers
2k views

Supermajority to prevent 51% attack?

I would think that amending the bitcoin protocol to require a supermajority, say 60% or 75%, to verify proof of work help reduce the risk of a 51% attack. If this is so, what are the major obstacles ...
0
votes
1answer
110 views

How is Coinbase any different than Mt Gox?

Apparently Coinbase handles the private keys for your wallet which allows them to easily handle buying and selling. As Coinbase is a hosted wallet, we do not provide users with their private ...
1
vote
1answer
86 views

How likely are key pair collision attacks? [duplicate]

Is it possible to be profitable by developing a collision application that continually and automatically generate a key pair, check for the existence of the public address in the block chain, and then ...
0
votes
0answers
34 views

Can't get armory to work

When I try running armory, it seems to download the block change and actually gets to 0 blocks, but then all of the sudden, armory disappears. Anyone know why this is happening? In the log file, I ...
2
votes
1answer
37 views

How are mutated transactions prevented from getting relayed?

Quoth Bitcoin release-notes-0.9.0.md: This release contains a few fixes for transaction ID (TXID) malleability issues: -nospendzeroconfchange command-line option, to avoid spending ...
5
votes
2answers
138 views

BItcoin value vs. Supercomputing

What protects the stability of bitcoin's value if supercomputers or some other technological breakthrough allows them to be mined at rates we have not anticipated?
4
votes
1answer
164 views

Is a full blockchain fork possible?

Let's say someone creates a blockchain fork starting from the genesis block, when the difficulty was absurdly low compared to today; then he starts mining new blocks from there up to the current block ...
2
votes
1answer
50 views

Can I detect a 51% attack as a developer

I am a developer building an application that accepts payments in cryptocurrencies. Is it possible, in the occurence of a 51% attack, to build a script that detect this, so we can suspend withdrawals ...
1
vote
2answers
262 views

Is the denumerability of private keys a threat?

Since the set of all private keys is denumerable, it is at least possible to create a searcheable record of all keypairs. Which, when finished, is a killer for the whole idea. Am I right or do I miss ...
3
votes
1answer
115 views

Detecting stolen bitcoins?

Is it possible to detect stolen bitcoins? With so many coins being stolen these days, for the more "ethically conscious" bitcoin users, is it somehow possible to check if the coins (you're about to ...
0
votes
0answers
58 views

Multisig transactions vs secret sharing

Some background here, I am implementing a wallet that enhances security by using smart cards. The card stores a pin protected key but unfortunately cannot do ECDSA signing. There is also a server ...
0
votes
1answer
51 views

Can a double spend attack be obfuscated by mimicking the transactions seen before the fork?

An attacker controls the majority of the hashing power and wants to double spend without arousing suspicion. If they mirror the public chain's activity while generating the private fork and the fork ...
9
votes
1answer
124 views

Heartbleed bug and Altcoins

Bitcoin recently released V 0.9.1 patching vulnerabilities from the Heartbleed bug, however I have not seen anything from any alt coin. What are the possible security risks associated with using these ...
9
votes
5answers
296 views

What would a new exchange need to be better than the rest?

If a new crypto v crypto exchange were to be built and launched. What would tempt you to use it rather than what you currently use? Or what improvements would you like to see from the way things work ...
2
votes
2answers
224 views

I think my bitcoin wallet was hacked. What to do?

I opened bitcoin-qt after not mining for a couple months and found that I suddenly have no more bitcoins! And I see that there were 2 transactions that I did not authorize sending my coins to other ...
0
votes
1answer
67 views

What are the methods for getting an old, used windows P.C. ready for secure Bitcoin usage? [closed]

Let's say I am about to set my Grandmother up with a wallet. I have no idea what she has on her computer. There could be a host of malware, keyloggers etc. Let's also say that a complete wipe and ...
0
votes
3answers
95 views

Does Bitcoin's SHA256 proof make a 51% attack more likely?

Ethereum's description says that Bitcoin's mining algorithm requires only a simple SHA256 computation, which caused the creation of specialised ASICs, which centralizes mining in the hands of a few ...
0
votes
3answers
198 views

TorBrowser + HTTPSEverywhere Blockchain.info wallet safe?

I seem to find conflicting information regarding the possibility of a TOR exit node stealing my data even while using HTTPS. How possible/likely is this? Let's assume user implements strong security ...
1
vote
1answer
163 views

Who can see my IP address while using Electrum

Who exactly is my IP exposed to when sending transactions in Electrum. I'm assuming the server operators can see it every time I connect (to query the servers about my balances). When I make a ...
0
votes
0answers
19 views

Proof of solvancy [duplicate]

Andreas has been talking a lot lately about proof of solvency as it pertains to any company that takes custodial custody of bitcoin funds. As someone who's planning to launch a project that does just ...
0
votes
1answer
97 views

Couldn't an attacker cause online (watch-only) wallets to display malicious receiving addresses?

If I understand correctly, one of the main perks of using a deterministic watch-only wallet is the ability to generate new receiving addresses without syncing with the offline wallet, but this seems ...
0
votes
1answer
111 views

Paper wallet generated client side and off network is not necessarily secure [duplicate]

One would think that if a person generated a private key client side and never exposed that key to the internet, that they would be secure. However, the risk is that the paper wallet generation code ...
2
votes
2answers
172 views

mtgox failure… any implications for bitcoin/ecurrency protocol design?

last heard, estimates are Mtgox lost about ~$½B ... apparently the current bitcoin market cap is around ~$8B ie Mtgox failure roughly somewhere around 1/16th the entire market cap of bitcoin, a ...
0
votes
2answers
178 views

Safest method while actually logging in and using blockchain.info wallet

Please help. I have finally set up my cold storage system for but I am too paranoid to login to blockchain.info wallet to send the funds out. Let's assume the account is safe and protected from most ...
1
vote
1answer
80 views

What is the function of the payload_checksum field in the Bitcoin protocol

According to the protocol specification at the Bitcoin wiki, each message header includes the first 4 bytes of sha256(sha256(payload) as a packet checksum. I suppose this checksum is used for packet ...
2
votes
2answers
159 views

What other currencies have same malleability vulnerability as Bitcoin? [closed]

Malleability of Bitcoin protocol has contributed to major losses and represents uncomfortable risk to Bitcoin investors in addition to possibility of 51% attack that depends on promise of biggest ...
2
votes
3answers
220 views

Does the Mt Gox attack constitute theft of Bitcoins or just a Denial-of-Service attack?

What's being reported on the news is that millions of Bitcoins were stolen from Mt Gox. But the Bitcoin Foundation blog says something different: https://bitcoinfoundation.org/blog/?p=422 ...
3
votes
2answers
981 views

How safe is my USD deposit at Bitstamp?

With Mt.Gox probably going insolvent/broke in these days, how safe is my USD account balance with Bitstamp? Is Bitstamp as a company registered with some financial institutions? Are customers USD ...
5
votes
2answers
238 views

Is there a way to stop a man-in-the-middle attack when communicating addresses?

Let's say you have person A who wants to pay person B. A common way for B to communicate his/her address to A is by QR code or email or some such non secure method either of which could be ...
3
votes
1answer
290 views

Does it hurt the network to reuse addresses?

There is already a question that ask why you shouldn't reuse addresses, but it's about whether or not it's a bad idea for the person who would do the reusing. I understand there are several reasons ...